thesis on evidence law

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28 Evidence Law

Gary Edmond is Professor of Law in the School of Law and Centre for Interdisciplinary Studies of Law at the University of New South Wales.

David Hamer is Associate Professor in Evidence and Proof at the Sydney Law School, University of Sydney.

• Published: 18 September 2012
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This article reviews contemporary response to several contrasting strands of recent empirical work. It begins with discussing the scope and rationale of evidence law. Experimental studies on eyewitness memory and testimony illustrate the potential value of empirical studies to the practice of investigations, prosecutions, and appeals. This article discusses several lines of empirical inquiry employing diverse methodologies, experiments, surveys, and approaches and reviews their limitations, and implications and significance for the understanding and practice of law. Many of the contributions from empirical legal studies are provisional and their precise value for practice is uncertain or ambiguous, but they raise important issues worthy of serious consideration. By identifying problems with eyewitness evidence and the limitations of many of the forensic sciences, and in many other ways, empirical and experimental studies have substantially outpaced legal experience. Indifference to empirical legal study is likely to reduce the social legitimacy of legal institutions.

Introduction   652

Evidence Law in the “ Rationalist Tradition” 653

Scope of evidence law 653

Rationale of evidence law 654

Diverse Empirical Studies   656

The exclusion and admission of hearsay 656

Expert opinion evidence 661

Subjective probability and human inference 666

Discussion   669

Abstraction from trial environment 669

Specificity of conditions, generalizability of conclusions 670

Factual uncertainty and the benchmark problem 671

Competing goals and values 672

Bigger pictures 673

Rationalist and Empiricist Legacies 674

I. Introduction

“E vidence law,” as a “subject suitable to be treated as a unified field of regulation and of study,” is a product of the Anglo-American adversarial tradition (Damaška, 1997 : 109). Continental civil law systems have fewer rules of evidence, and these tend to be associated with specific bodies of substantive law. While Anglo-American evidence law is broadly accepted as a relatively discrete domain, it is generally viewed as “labyrinthine” and “dishevelled,” “l argely ununified and scattered, existing for disparate and sometimes conflicting reasons … a mixture of astonishing judicial achievements and sterile, inconvenient disasters” (Damaška, 1997 : 10–11; Heydon, 1984 : 3).

There are many unanswered questions about evidence law, concerning its historical development, its various purposes, and the interrelation between its diverse components and other areas of legal and non-legal practice. Most, if not all, invite empirical inquiry. And yet, notwithstanding that evidence law is itself concerned with evidence and proof and is generally supposed to have developed in a “rationalist tradition” (Twining, 2006 : 75), legal practice and evidence scholarship have been remarkably indifferent, and even hostile, to empirical study and evidence-based proposals for reform. Political expediency and the experience of legal practitioners, especially the judiciary, appear to be more important than scholarly attempts to understand evidence law in terms of its legal and social context(s).

Rather than providing a comprehensive account of empirical studies pertaining to evidence law, our goal here is to present a brief review and contemporary response to several contrasting strands of recent empirical work. We begin by setting the scene with an outline of the scope and rationale of evidence law.

II. Evidence Law in the “ Rationalist Tradition”

A. scope of evidence law.

To varying degrees evidence law regulates the admissibility and presentation of evidence and fact-finding at trial. The trial is a highly formalized system of empirical enquiry, operating within a prescribed procedural framework. In a jury trial, the jury is responsible for fact-finding while the judge determines the applicable law. In the absence of a jury the judge is responsible for legal and factual decisions. Jury trials are becoming increasingly rare, though a notional bifurcation between the tribunal of law and tribunal of fact remains.

In the adversarial tradition the parties identify the areas of factual dispute, and decide what evidence to make available to the court. At trial the plaintiff or prosecutor presents her case first, and then, if there is a case to answer, the defendant makes his case. Most evidence takes the form of witness responses to questions directed by the parties, though the traditional preference for oral evidence is in decline, as documentary evidence and “paper trials” become more prevalent, most conspicuously in civil litigation without juries. Those few disputes which are not abandoned or negotiated are generally litigated through a single continuous trial. While jury decisions, incorporating factual reasoning and the application of law to facts, are left unexplained, in many jurisdictions judges provide reasons for interlocutory decisions and their verdicts.

The trial judge should only admit evidence that is relevant to a fact in issue and survives exclusionary rules, such as those pertaining to hearsay, opinion, bad character, propensity, and so on. Evidence that is otherwise admissible may nevertheless be excluded as a matter of judicial discretion, for example, due to the risk of unfair prejudice to the defendant, or the public policy against obtaining evidence in certain ways (such as through physical coercion). Litigants, witnesses, and interested parties may also be able to prevent the admission of evidence by the exercise of legal professional privilege, the privilege against self-incrimination, and public interest immunity.

Once all of the evidence has been tendered, the judge will instruct the jury as to how it can be used. In a judge-only trial interlocutory decisions and instructions often form part of the written judgment. While evidence law is concerned primarily with admissibility rather than weight, some types of evidence—such as eyewitness identification and the testimony of prison informants—give rise to special concerns and the fact-finder will be directed to exercise special caution. The trial judge also instructs the jury on the burden of proof. Generally, the state (or prosecution) must prove a defendant's guilt beyond reasonable doubt, and a civil plaintiff must prove liability on the balance of probabilities (or preponderance of evidence).

Appeals are frequently focused on the (mis)application of rules of evidence (and practice), usually the admission of inadmissible evidence and/or the exclusion of admissible evidence. Appeals on matters of fact are more restricted, though possible where the evidence does not support the verdict or some new (or “fresh”) evidence emerges after the verdict or appeal.

B. Rationale of evidence law

Evidence law, as the foregoing discussion indicates, consists of a mass of rules and exceptions, many of which confer choices, discretions or require particular actions. Whether they can be coherently accommodated within a single theoretical framework is open to question. Most scholars have viewed evidence law as being concerned with “rational methods of determining questions of fact,” in which a central goal is to “maximize accuracy in fact-determination”(Twining, 2006 : 76). Jurists have debated how accuracy is best achieved, and the relative weight to be assigned to sometimes competing goals—such as efficiency, due process, and accuracy—though, these debates have been conducted almost entirely within this shared rationalist tradition.

One major ongoing debate concerns freedom of proof (Twining, 2006 : 43–4;Stein, 2005 : 107–16). Factual inquiries in other spheres of endeavor are not governed by formal rules, so why are legal disputes governed by rules of evidence? In the Anglo-American legal tradition evidence law (along with the choices and discretions it confers) now exerts far greater influence on practice than in most other legal traditions (Damaška 1997 : 19–20; cf. Gluckman, 1955 ), routinely excluding evidence on various grounds. As early as the turn of the nineteenth century Jeremy Bentham ( 1843 : VII, 24) forcefully opposed this approach: “Evidence is the basis of justice: to exclude evidence is to exclude justice.”

Various justifications have been offered for Anglo-American exclusionary rules. One is provided by the “best evidence” rationale (e.g., Gilbert, and Nance)—encouraging the parties to uncover and provide stronger alternatives to the excluded evidence. Exceptions to exclusionary rules are frequently grounded in necessity—particularly the absence of alternative evidence. But this reveals a potential weakness with handing responsibility for gathering and presenting evidence to the parties. Understandably, parties consider utility as well as reliability. Why then are parties afforded so much control? This freedom reflects the Anglo-American perception of the trial, not only as a vehicle for the pursuit of truth and justice, but also as a means of socially legitimate conflict resolution (Damaška, 1997 : 110–11; Tyler, 1990 ).

Another common explanation for exclusionary rules focuses on the position of the jury as fact-finder (e.g., Thayer, 1898 and Wigmore, 1940 ). Evidence is excluded because of the danger that the jury will improperly value it. This, of course, immediately raises supplementary concerns. If lay juries cannot be trusted with the evaluation of evidence, then why should they be used as fact-finders? Persistence with the jury might suggest it serves several functions, including a celebrated form of participatory democracy and a means to disseminate social norms (Damaška, 1997 : 29). However, the jury's ability to handle complex evidence and the effects of popular beliefs and culture (exemplified in high-rating television shows such as “CSI: Crime Scene Investigation”) remain controversial (Cole and Dioso-Villa, 2009 ).

Both the jury's role and the scope of exclusionary rules have tended to diminish over time. The general trend has been in the direction of free proof. However, in recent years several scholars have resisted this trend, either questioning the attribution of some putatively proper value to the evidence (e.g., Edmond) or seeking to demonstrate the importance of values other than accuracy (Ho, 2008 ;Stein, 2005 : 133).

III. Diverse Empirical Studies

Empirical research is being undertaken in many areas of evidence law. Perhaps the most influential body of work has been directed toward eyewitness evidence (e.g., identification evidence), in part, perhaps, because it involves a neat factual issue with few normative complications (Park and Saks, 2006 : 960, 973).

Experimental studies on eyewitness memory and testimony illustrate the potential value of empirical studies to the practice of investigations, prosecutions and appeals. Of scholarly interest for more than a century, from the 1970s psychologists, such as Elizabeth Loftus and Gary Wells, began to conduct systematic experiments on the ability of people to remember things, particularly past events and the identity of persons of interest. Subsequent research focused on how the conditions of observation and investigative processes might influence (and compromise) memory and on ways of improving investigative procedures so as to minimize risks of contamination, suggestion, and displacement.

This research has exerted a positive influence on the ways police, trial and appellate courts respond to identification evidence, although the substantial and convergent results of numerous experimental studies have not been fully implemented (Park and Saks, 2006 : 960–4). Most jurisdictions routinely allow investigators and others to subvert protections designed to enhance the reliability of eyewitness testimony, and retain practices and directions that are antiquated in terms of empirical research and mainstream academic consensus (Wells and Quinlivan, 2009 ). Further, in many jurisdictions, psychologists are not permitted to explain to fact-finders the general problems with identification evidence or known problems with particular practices or specific circumstances. And yet research on wrongful convictions demonstrates that even in sexual assault cases, where the eyewitness often has a relatively good opportunity to observe the offender at close proximity, mistaken eyewitness identification is notorious (see Figure 3 ).

The reluctance to engage with empirical legal studies is an issue to which we will return. In the remainder of this section we report on research in three domains more fraught than eyewitness memory, namely hearsay, expert evidence, and probabilistic reasoning. The studies discussed below illustrate great diversity in empirical research styles, the types of scholars involved, the mix with theory and data, the socio-political implications, and the scope the research creates for intervention and change.

A. The exclusion and admission of hearsay

Ordinarily, witnesses give sworn testimony about their observations, and are available for cross-examination. The hearsay witness, however, testifies as to what someone else (the “declarant”) has said about her observations. Relative to ordinary evidence, hearsay evidence involves at least one additional step, making the fact-finder more remote from the event under consideration (Figure 1 ). The traditional bases for exclusion are that the declarant's out-of-court statement is not under oath and the declarant is unavailable for cross-examination.

Thompson and Pathak's   1999 : 457) “hearsay chain”

Damaška ( 1997 : 1), a comparativist, describes the hearsay rule as “so bizarre [as to] occupy one of the most forbidding corners of the entire Anglo-American legal structure.” The stringency of the historical rule has been tempered by numerous exceptions, but these have added complexity to legal practice. The modern rule, as Rakos and Landsman ( 1992 : 668) report, “remains an amalgam of concerns about juror competence, cross-examination, and fairness.”

Most of the empirical work on hearsay has been carried out by psychologists. Following Hugo Munsterberg's, On the Witness Stand (1908),Hutchins and Slesinger (1928) drew upon the psychological literature to question the rule's scientific legitimacy. However, with few exceptions, only in the last two decades have experimental psychologists and lawyers approached hearsay rules and evidence in ways that transcend historical and doctrinal approaches or attempts to make extant psychological knowledge accessible to a legal audience (McGough, 1999 : 487). Here, we review recent experimental research relating to mock juror assessment of hearsay evidence and related work focused on the hearsay evidence of children.

1. Mock juror responses to hearsay evidence

The first experimental studies endeavored to determine whether jurors overvalue hearsay evidence. In the early 1990s, Rakos and Landsman systematically manipulated the strength of hearsay testimony across versions of a trial transcript pertaining to a prosecution for theft and compared the mock juror responses. They concluded that the “mere introduction of hearsay testimony may not disproportionately influence juror decisions” (Rakos and Landsman, 1992 : 664).

Miene, Park, and Borgida drew similar conclusions. They compared responses to combinations of circumstantial, hearsay and eyewitness testimony using a video simulation of a theft trial. The eyewitness and hearsay witness provided virtually identical evidence, and participants in the hearsay condition received cautionary instructions. These researchers found that participants in the hearsay condition were less likely to produce a guilty verdict and rated the hearsay testimony as less important, influential, and reliable than those responding to eyewitness evidence. This led the investigators to question one of the major rationales for the exclusionary rule: “the data from this study suggests that hearsay as a form of testimony is not overvalued by jurors, as some legal scholars have suggested” (Miene et al., 1992 : 699).

Kovera, Park, and Penrod also expressed confidence in juror abilities, at least in relation to hearsay. Their mock jurors were “more sceptical of the value and reliability of hearsay testimony than of eyewitness testimony” and, further, gave more weight to hearsay testimony when there was a short delay (one day) as opposed to a longer delay (one week) (Kovera et al., 1992 : 719). However, these mock jurors, also exposed to eyewitness identification evidence, were apparently insensitive to its limitations, particularly the corrosive effects of delay.

In contrast, Paglia and Schuller 1998 formed a less favorable view of juror reasoning. Participants in their experiments used hearsay evidence in ways that were inconsistent with judicial instructions included in the audio recording of a mock trial. Regardless of their form and timing, cautionary instructions about prosecution hearsay evidence exerted little discernible impact on the decisions. In an earlier study, focused on exculpatory hearsay provided through an expert witness, Schuller ( 1995 : 359) found that the participants had difficulty ignoring hearsay evidence even when instructed to do so.

2. Persuasiveness and reliability of children's statements

A prominent strand of hearsay research focuses on out-of-court declarations by children. This type of hearsay, common where sexual assault is alleged, is of interest for a number of reasons. Early reports may be valuable as the memory of children is especially vulnerable to influence and degradation. Concerns also arise about child complainants being traumatized by testifying in court in the presence of the alleged perpetrator (Buck et al., 2004 ). More broadly, there is widespread social concern about pedophilia, but relatively low rates of complaint, prosecution, and conviction. In this environment, many jurisdictions have made special provision to admit the out-of-court statements of children, and researchers have sought to understand their potential effects (McGough, 1999 ).

Initially research focused on the believability of hearsay evidence and whether jurors might convict in cases of alleged sexual assault where the child complainant does not testify. In an experiment using a fictional summary of a child sexual assault trial, Golding, Sanchez, and Sego found that the child complainant's testimony was considered more believable than the child's complaint presented as hearsay. Nevertheless, the hearsay evidence seemed to influence “conviction” decisions and the authors concluded that “it may not be necessary for the alleged victim to testify on her own behalf for the defendant to be judged culpable” (Golding et al., 1997 : 318).

Subsequent research considered the identity and status of the hearsay witness. Using a “highly realistic” video of a sexual assault trial, Ross, Lindsay, and Marsil concluded that the persuasiveness of child testimony in hearsay form depended upon the identity of the hearsay witness. Apart from one condition, where the hearsay witness was the mother of the complainant—embroiled in a “heated divorce” with the alleged perpetrator—the child's testimony was “significantly less likely to produce ‘guilty votes’ ” than the evidence of the mother, the child's doctor and teacher (Ross et al., 1999 : 450–1). Studying the effects of the ages of the complainant and the hearsay witness, Golding, Alexander, and Stewart (1999) found that mock jurors split along gender lines, with women generally more likely to accept the hearsay evidence of assault.

So far, the studies in this subsection have focused on the persuasiveness of hearsay evidence. Another strand is concerned with reliability and the competence of jurors. Pathak and Thompson 1999 sought to address a limitation with the studies by Rakos and Landsman 1992 , Miene et al. ( 1992 ), and Kovera et al. ( 1992 ). These earlier studies had concluded that “hearsay is unlikely to be overvalued,” yet they did not include an “objective or normative standard against which to compare [mock] jurors' evaluations.” Pathak and Thompson sought to test “people's inferences about the reliability of hearsay evidence in circumstances that allowed the actual reliability of the evidence to be objectively verified” (1999: 373). They contrived a situation where they covertly controlled a (child) witness's experiences of a mock janitor's behavior and elicited an account through questioning.

Following a complaint, children are usually interviewed by social workers, police, or other professionals. Pathak and Thompson's experiments considered how hearsay is evaluated depending on whether the child is interviewed in a suggestive or neutral manner. They concluded that mock jurors failed to take sufficient account of suggestive questioning:

Although the videotaped “hearsay witnesses” commented on the suggestiveness of the interrogations with the child, the “jurors” did not realize that the suggestive interrogations had a greater influence on children's reports than the neutral interrogations (Pathak and Thompson, 1999 : 381).

Where there is no video or audio recording, the hearsay testimony of the interviewer, along with any notes, may be the only “record” of such exchanges. As Warren and Woodall 1999 : 356) explain, “to properly evaluate a child's statements presented through hearsay, jurors and fact finders need to hear not only what the child said (the gist of the interview), but how it was said (a verbatim account including specific questions and answers).” They found that while interviewers recalled the gist of interviews accurately, they incorrectly recounted the use of open-ended questions even when they made extensive use of specific and leading questions. Further, “[e]ven immediately after an interview, important content was omitted from hearsay accounts, and the majority of the verbatim information (specific wording and content of questions and answers) was lost” (Warren and Woodall, 1999 : 369). Their conclusion: “asking adults to recreate the structure of their conversations or interviews with children after the fact (i.e. during courtroom testimony) is risky” (ibid: 365).

These preliminary results prompted further investigation. Warren, Nunez, Keeney, Buck, and Smith compared the impact on mock jurors of: (1) a video of an interview with a child; (2) the interviewer providing a verbatim account of the interview; and (3) the interviewer providing the gist of the interaction. Participants rated the credibility of the adult gist witness “higher than that of the verbatim witness or child witness, and the verbatim witness was rated as significantly more credible than the child” (Warren et al., 2002 : 852; cf. Golding et al., 1997 ). Gist evidence was perceived as less suggestive, more spontaneous and more open-ended. Counterintuitively, the greater the displacement of the interview from the testimony, the more persuasive it seems to have been (Warren et al., 2002 : 850–1). Results such as these led Buck, Warren, and Brigham to suggest that the use of video or a transcript would provide “a better compromise between protecting the child and the rights of the defendant than the use of testimony by a hearsay witness” (Buck et al., 2004 : 618–20).

Finally, one of the most recent studies examined “the veracity of children's accurate, unintentionally false, or intentionally false eyewitness reports” (Goodman et al., 2006 : 368). Like the study by Pathak and Thompson, it was undertaken in circumstances where the child's experience it was controlled. Young children reported being touched on the stomach, nose, or neck by a “defendant.” Some children who had not been touched during the play session were instructed to falsely claim that they had been. Comparisons were drawn between mock juror responses to live testimony, video of forensic interviews with a social worker, and the social worker testifying about what the child had said during the interview.

The conclusions might be considered disconcerting:

First, this study demonstrates, quite provocatively, that children coached to lie can maintain that lie in the face of repeated questions. In fact, children who were instructed to “fool” the interviewer (and the others in the mock trial) were often more consistent in their claims than children who really had been touched. … Second, our results indicate that adults, when faced with the task of determining whether unauthorized touching of a child occurred, were poor at distinguishing whether a particular child was lying or telling the truth. Furthermore, adults' abilities were neither helped nor hindered, for the most part, by seeing the child live or on videotape, or by hearing a social worker recount what the child said. … Third, [mock] jurors relied on predictable aspects of the children's accounts when making judgments about the veracity of the allegations … jurors tend to use witness consistency as an indicator of accurate statements. However, … ironically it was the liars—not the truth-tellers—who were more consistent, particularly in the two hearsay conditions (Goodman et al., 2006 : 390–1).

B. Expert opinion evidence

Opinion evidence is also subject to exclusion. As far as practically possible, witnesses should describe their sensory perceptions in concrete factual terms, without the overlay of interpretation or opinion. A very important exception to this exclusionary orientation is opinion evidence provided by experts. Where, by reason of “specialized knowledge,” a witness can provide a relevant opinion that is beyond the ken of the average juror, that opinion may be admissible.

Until quite recently the most important empirical work on experts was primarily qualitative or historical (e.g., Jasanoff, Jones, and Golan). Case studies, and a few surveys, examined the roles of expert evidence in public inquiries (e.g., Wynne), litigation clusters (e.g., Schuck, Green, and Sanders); miscarriages of justice (e.g., Nobles and Schiff; Dwyer, Neufeld, and Scheck; and Gross); civil litigation (e.g., Shuman, Champagne, and Whittaker); and civil justice procedures such as court-appointed experts and concurrent evidence (e.g., Cecil and Willging, and Edmond). Scholars, such as Monahan and Walker, were influential in documenting the legal uses of social scientific evidence. Empirical research, particularly quantitative work, has increased in recent years as long-standing concerns about partisanship, expense, comprehension and reliability have become more prominent, particularly in response to social and legal developments in the United States.

1. Admissibility decision-making in the United States

One important strand of empirical research has focused on the impact of the U.S. Supreme Court's Daubert v. Merrell Dow Pharmaceuticals, Inc . (1993) decision. Daubert was an appeal over the admissibility standard for expert evidence under the Federal Rules of Evidence (1975). There, the Court explained that scientific evidence must be both “relevant and reliable” and emphasized the trial judge's gate-keeping responsibility. The majority provided four criteria to help trial judges determine the reliability of scientific evidence. The criteria are whether the theory or technique: (1) has been tested (referring to Karl Popper's notion of “falsifiability”); (2) has been published and/or peer-reviewed; (3) has a known or potential rate of error; and (4) is “generally accepted” in the relevant specialist community. The last of these was drawn from Frye v. United States (1923).

Frequency with which reliability was addressed and evidence was found unreliable.

Reprinted with permission from Dixon and Gill ( 2002 : 273).

In the aftermath of Daubert , Dixon and Gill examined 399 decisions issued in civil proceedings between 1980 and 1999. Starting in the early 1990s the number of challenges to the reliability and admissibility of expert evidence began to rise (Figure 2 ). They concluded that the “standards for reliability have tightened” and judges “have become more watchful gatekeepers” against expert evidence proffered by plaintiffs.

The number of successful challenges began to decline after 1996–1997 which Dixon and Gill thought might be attributable to changes in the behavior of lawyers and parties as they gradually “tailored the evidence … to the new standards” (Dixon and Gill, 2002 : 299).

These findings were generally consistent with the results of investigations by Krafka et al. ( 2002 ). These scholars surveyed federal district court judges in 1991 (responses = 335) and 1998 (responses = 303) about their most recent experience with expert evidence in a civil case. More judges excluded expert evidence in 1998 (41 of cases) than in 1991 (25%). There was also an increased use of pre-trial admissibility hearings (that became known as Daubert hearings). Just over half of the judges reported using pre-trial hearings in 1991 whereas more than three-quarters reported using Daubert hearings in 1998 (p. 327 ).

Interestingly, Krafka et al. found that the actual Daubert criteria did not seem to play an important role in these developments:

Judges who excluded testimony in the recent survey did so most often because it was not relevant, the witness was not qualified, or the testimony would not have assisted the trier of fact. These reasons are similar to the reasons most frequently cited by judges in 1991, and they do not reflect the factors cited in Daubert (Krafka et al., 2002 : 330).

Further insights into the impact of Daubert were provided by Cheng and Yoon 2005 . They examined the rate at which defendants removed cases from state to federal courts in tort and product liability suits—which are usually dependent on expert evidence. Daubert is binding on all federal courts, but only some state courts. A higher rate of removal from non- Daubert states (e.g., Frye jurisdictions) than from Daubert states would suggest that defendants thought they had a greater chance of excluding plaintiffs' expert evidence under Daubert . Cheng and Yoon ( 2005 : 503) found that the difference was not statistically significant, and inferred that “debates about the practical merits and drawbacks of adopting a Frye versus a Daubert standard are largely superfluous.” This was not to deny that Daubert had an impact, but its exclusionary influence seems to extend to non- Daubert jurisdictions: “[T]he power of the Supreme Court's decision was not so much in its formal doctrinal test, but rather in its ability to create greater awareness of the problems of junk science” (Cheng and Yoon, 2005 : 503; Harris 2008 ).

2. The forensic “sciences ”

Most of the admissibility studies have focused on civil litigation. However, a study of criminal appellate decisions between 1988 and 1998 suggests that Daubert may have exerted a more limited impact on criminal proceedings. Groscup et al. ( 2002 ) observed more “discussion” of expert evidence in judgments after Daubert , but no change in the proportion of evidence excluded in criminal proceedings. These researchers also noted the “mysterious … lack of discussion” of the Daubert criteria, particularly “falsifiability, peer review, and error rates” (p. 353 ).

The “exclusionary ethos” associated with civil proceedings does not seem to have been applied, and certainly not with the same level of rigor, to forensic science evidence produced and relied upon by the state. Studies of commonly admitted forensic science techniques—including fingerprint, voice, image, bite mark, hair, and footprint comparisons, document examination, blood spatter analysis and so on—reveal that: most have not been validated; error rates are often unknown; “expert” witnesses are often poorly educated (relative to research scientists); systemic bias and exaggeration are ubiquitous; and limitations and problems, even if known, are not always disclosed or explained during criminal proceedings (Saks and Koehler, 2005 ).

A recent review of institutionalized forensic sciences by the U.S. National Academy of Sciences (NAS) lamented that:

With the exception of nuclear DNA analysis … no forensic method has been rigorously shown to have the capacity to consistently, and with a high degree of certainty, demonstrate a connection between evidence and a specific individual or source (NAS, 2009 : 5). Figure 3 Open in new tab Download slide Analysis of incriminating evidence in DNA exoneration cases Reprinted with permission from Saks and Faigman ( 2008 : 172)

Reviews, such as those associated with Innocence Projects (Figure 3 ), suggest that mistaken or misleading forensic science evidence is a feature in many wrongful convictions (Garrett and Neufeld, 2009 ; Findley, 2008 ).

Several psychologists, lawyers, and scientists, responding to these disturbing revelations, have characterized the identification sciences as the “nonscience forensic sciences” (Saks and Faigman, 2008 : 149).

3. Surveys of judicial understanding of “science”

The focus on admissibility standards in recent decades has also generated interest in judicial understanding of the Daubert criteria. One explanation for the ostensible lack of engagement is provided by Gatowski, Dobbin, and their colleagues.

Gatowski et al. (2001) surveyed hundreds of judges about the Daubert criteria. They asked questions designed to elicit information about judicial understanding of falsification (“Falsif.”), error rates (“ER”), peer review and publication (“PR/ Pub.”) and general acceptance (“GA”). The results, presented in Figure 4 , led them to conclude:

[M]ost judges have a questionable level of understanding with respect to the basic concepts of science, or of most Daubert guidelines and their underlying scientific meaning, with the concepts of falsifiability and error rate particularly problematic for many judges (Dobbin et al., 2007 : 13).

Such results are often used to ground reforms, particularly proposals based on judicial re-education, although their implications for fact-finders are less clear.

“Understanding × Guideline”

Reprinted from Gatowski et al. ( 2001 : 445) with kind permission from Springer Science+Business Media.

4. (Reflexive) interventions in the “fingerprint wars ”

One interesting aspect of the controversy over the forensic sciences (and judicial scientific literacy) emerged out of recent contributions from post-Kuhnian Science & Technology Studies (STS). STS scholars form part of a scholarly tradition that values qualitative empirical investigation of what scientists, doctors and engineers actually do. On the basis of laboratory (and other workplace and institutional) studies they have concluded that scientists do not adhere, in any simple way, to a prescriptive scientific method doctrine (such as falsification) and are not consistently constrained by universal norms (such as disinterestedness and skepticism).

STS has much to say about law-science interactions (e.g., Jasanoff, 2008 ). Simon Cole's work on fingerprints is of particular interest in the present context. Cole has produced impressive scholarly accounts of problems with individualization, validation, and the social organization of fingerprint examiners. He has also appeared as an expert witness, contesting the admissibility and probative value of fingerprint evidence. Through a commentary on his participation in a Daubert hearing, Cole and Michael Lynch explored some of the dilemmas encountered when an STS scholar is confronted with a challenge to the admissibility of his own expert evidence (Lynch and Cole, 2005 ).

In People v. Hyatt (2001) Cole had to carefully negotiate questions about his expertise and interventions. Did it matter, for example, that he was not a fingerprint examiner? Was he a scientist or something else (such as historian, sociologist, or meta-expert)? What were the practical and theoretical difficulties involved in demarcating between genuine science and fingerprint evidence? Was it appropriate for an STS scholar to embrace the Daubert criteria in order to impugn fingerprint evidence? What are the practical limits of epistemic radicalism? And, could tacit knowledge and experience (central to many STS analyses) be used to excuse limitations with fingerprint identification? Resolving these and other dilemmas raised a series of tricky practical and theoretical issues.

Cole, whose opinion evidence has been admitted in other cases, approached his performance as an expert witness pragmatically. Nevertheless, the judge in Hyatt excluded his opinion evidence as “junk science” while admitting the impugned fingerprint evidence. This pejorative rejection provided ammunitionfor Cole's detractors in the continuing controversy over the reliability of fingerprint evidence. Discussing his ongoing “participation” more recently,Cole 2009 questioned the generalizability of particular experiences in court, stressed the protracted nature of the “campaign” to improve fingerprint evidence and placed his activities in the context of broader criticisms of the forensic sciences. Reflexively, and defensively, Cole also explained that exclusion and not “winning” in a Daubert hearing (or trial) cannot simply be equated with “failure.” The exclusion of his opinions in Hyatt , for example, may have actually discredited the judiciary and the institutionalized forensic sciences, thereby consolidating support and allies in the ongoing campaign (e.g., NAS, 2009 ). Cole's ( 2009 : 135) work demonstrates the difficulty of intervening to effect legal change and confirms that judgments about interventions can be just as “difficult and ambiguous” as the interventions themselves.

C. Subjective probability and human inference

The studies discussed in sub-sections A and B concern the operation of exclusionary rules. However, once evidence is admitted, fact-finders are largely unconstrained as to how it is used. This raises empirical and normative questions about how human inference operates and its accuracy.

Considerable research has been undertaken in this area over the last few decades. In experiments conducted by Daniel Kahneman, Amos Tversky, and others (e.g., Gilovich et al., 2002 ) the probabilistic reasoning of participants was found to depart from that prescribed by Bayes's Theorem—a rule of probability theory which provides a means by which a prior probability assessment can be updated to take account of the impact of additional evidence. Investigators suggested that, rather than reasoning probabilistically, humans may employ a limited number of inference mechanisms or “heuristics,” which sometimes produce a “bias.” Gerd Gigerenzer and others responded to the negative implications of the “heuristics and biases” (H&B) studies by emphasizing the ecological rationality of heuristics. For Gigerenzer and his colleagues, heuristics operate effectively—often more effectively than the “normative” Bayesian methods of the H&B researchers—in the environments in which they are typically employed (Gigerenzer and Selten, 2001 ; for legal implications, see Saks and Kidd, 1980 ; Gigerenzer and Engel, 2006 ).

Another significant contribution is Pennington and Hastie's “story model” of juror decision-making (1992). This descriptive model encompasses the juror's various tasks at trial, from the hearing of evidence right through to the selection of a verdict. According to the fact-finding component of the model, the juror settles upon a version of facts by organizing the evidence into one or more stories. The acceptability of a particular story is governed by a set of certainty principles, such as coverage, coherence and uniqueness.

Here we focus upon a strand of research informed by the H&B endeavors and connected with the story model. This work, inaugurated by Gary Wells 1992 , investigates the relationship between fact-finders' subjective probability assessments and liability verdicts.

Wells's experiments all took a similar form. In the first experiment, for example, participants were given the following information. A woman is suing the Blue Bus Company (BBC) for having caused the death of her dog. It was killed by the reckless driving of a bus driver. The woman is color blind. Only two bus companies use that road. BBC runs 80 of the buses on the road and the Grey Bus Company (GBC) runs the other 20. Wells's second experiment contained the same basic information except that the volume-of-traffic data was replaced with the evidence of a weigh-station attendant. He logged a blue bus passing along the road just before the accident, but his log entries are only 80 accurate. In both the volume-of-traffic and weigh-station-attendant versions, most participants said there was an 80 probability that the dog was hit by a blue bus. This would appear to satisfy the civil standard of proof requiring a “preponderance of probabilities.” However, whereas a clear majority of participants would hold BBC “liable” in the weigh-station-attendant version (67.1 ), very few participants would on the basis of the volume-of-traffic data (8.2).

Wells conducted further experiments with slight variations in order to understand why a high subjective probability was viewed as an insufficient basis for liability in certain situations. He tested the hypothesis that fact-finders have a preference for causally strong evidence by replacing volume-of-traffic data with accident statistics. The bus company that is involved in more accidents may, for example, have poorer drivers, which may be the explanation for the occurrence of this particular accident. However, with this evidence most participants were still not prepared to make a finding of liability. The hypothesis that jurors were concerned with distributional fairness was also rejected A verdict based upon the volume-of-traffic data would blame all the accidents on the company that happened to run the majority of buses along the route. Instead, the participants were given forensic evidence that tire tracks on the dog matched 8 out of 10 of BBC's buses, but only 2 out of 10 of GBC's buses. Utilizing this kind of evidence, a company's liability would tend to be in proportion with the company's involvement in accidents. Participants arrived at a “correct” probability assessment but remained reluctant to assign liability.

Wells's final experiment again involved matching tire tracks. On this occasion, the forensic witness testified that the technique is 80 reliable, and expressed his belief that the dog was run over by a BBC bus. In this tire-track-belief version most participants were prepared to attribute liability to BBC. Wells explained these results in terms of a preference for “bidirectional” evidence: “in order for evidence to have a significant impact on people's verdict preferences, one's hypothetical belief about the ultimate fact must affect one's belief about the evidence” (1992: 746). Only in the weigh-station-attendant and tire-track-belief variations would the fact that a GBC bus hit the dog invalidate the evidence. The evidence in the other variations, although making it more likely that a BBC bus hit the dog, is consistent with it having been a GBC bus.

Two groups of investigators subsequently confirmed the “Wells effect” but questioned Wells' fact-to-evidence hypothesis. Niedermeier et al. ( 1999 : 534) suggested that it attributed to participants a “rather complex process” for dealing with the evidence. Sykes and Johnson ( 1999 : 201) suggested that Wells's hypothesis “constitutes more of an analytical description of the phenomenon than a theoretical account of why it occurs.” Both groups sought an alternative and simpler explanation for the “Wells effect.” Experiments led to the rejection of an obvious possibility-that participants would prefer to base a finding of BBC's liability on the professed belief of a witness rather than statistical data (Sykes and Johnson, 1999 : 204, 208; Niedermeier et al., 1999 : 536).

Ultimately, both groups advanced similar explanations for the “Wells effect.” Niedermeier et al. suggested that participants may be less prepared to hold BBC liable where they can “more easily think of or about an alternative scenario in which [BBC] is not liable” (1999: 537). Sykes and Johnson contended that participants would be less prepared to believe an event where it is “relatively easy … to imagine an alternative … and to regard this alternative as a plausible scenario” (Sykes and Johnson, 1999 : 202). The evidence in all versions supports an 80 probability of BBC's liability but the evidence in the tire-track, accident-statistics, and volume-of-traffic versions expressly refers to the possibility of GBC liability, and therefore allows the creation of a scenario where a GBC bus hit the dog.

While the investigators identified a connection between their hypothesis and the “story model” of Pennington and Hastie, it should be noted that the present hypothesis is concerned with the ease or difficulty of imagining the “alternative scenario” or “counterfactual” rather than the liability scenario itself (Sykes and Johnson, 1999 : 205; Niedermeier et al., 1999 : 540 fn 5). For Sykes and Johnson, the decisive factor is “the difficulty of mutating [the liability scenario] into the alternative possibility involving the grey bus” (Sykes and Johnson, 1999 : 210).

One additional point is worth mentioning. Wells suggested that his experiments revealed a situation where the participants' subjective probabilities were “statistically correct” (1992: 739), unlike those in the H&B research, but participants were reluctant to find liability on this basis. Sykes and Johnson questioned this interpretation, explaining that “there may be a difference between calculated probability estimations based on participants' understanding of the rules of probability, and measures affecting participants' ‘gut feeling’, or subjective sense of the likelihood of an event” (1999: 201). To test this, Sykes and Johnson asked participants to record both the “probability” that the bus was blue, and “how certain they felt … [based] on intuition or their ‘gut feeling’ ” (p. 204 ). They found that, unlike “probability,” “[s]ubjective certainty was … significantly affected by evidence form, and … was a significant mediator of liability” (p. 209 ). This suggests a stronger link with the H&B work: the divergence between the subjective certainty and statistical probability might be viewed as a “bias.”

IV. Discussion

Having briefly reviewed several lines of empirical inquiry employing diverse methodologies—experiments, surveys, quantitative and qualitative approaches—we now discuss some of their limitations, and their implications and significance for the understanding and practice of law.

A. Abstraction from trial environment

Research on juror reasoning relied upon experiments that were, in various ways, abstracted from the trial environment, thereby raising issues of ecological validity. Do real jurors, for example, behave like the “mock jurors” of the experiments? And, do the experiments resemble real world trials. Much of the information in the hearsay and human inference studies was presented via written summaries, audio and video recordings or, at best, via live actors. (An exception is Goodman et al.'s (2006) experiments where, in one variation, children reported their actual experiences to mock jurors.) The presentation of evidence in such forms is questionable, and particularly problematic in relation to hearsay, because the rule is directed toward providing fact-finders with first-hand accounts. In some of the studies, the “non-hearsay evidence” was, strictly speaking, hearsay, while the “hearsay evidence” was actually hearsay upon hearsay.

A related problem is that the participants tended to be provided with a single piece of evidence in isolation. The subjective probability studies were, in part, concerned with the impact of naked statistical evidence on fact-finders. However, it is questionable whether any piece of evidence can be truly naked. As Sykes and Johnson observed, “our study does not assess whether the effects for our manipulation may be attenuated by other factors that exist in the information-rich forum of an actual trial” (1999: 211). And, here we should not overlook procedures and strategy as well as other evidence.

Many of the hearsay studies compared mock-juror responses to hearsay evidence with their responses to the observer/declarant's testimony with essentially the same content. But this misses another significant epistemic effect of the hearsay rule. By requiring the actual observer of the events to testify (rather than someone who merely heard about them), it may be possible to obtain further detail, particularly through cross-examination. This additional testimony may be relevant both to the events in issue and the declarant's credibility. As far as the comparison between hearsay evidence and declarant testimony is concerned, this additional testimony may confer a greater epistemic advantage to the fact-finder than the declarant's oath or demeanor.

B. Specificity of conditions, generalizability of conclusions

An empirical experiment inevitably involves a quite specific set of conditions raising a question as to the generalizability of any conclusions from that experiment. Of course, variations can be introduced through further experiments. Across the hearsay studies, for example, variations included: different ages of declarants and hearsay witnesses; different types of relationships between declarants and hearsay witnesses; differences in the status and experience of the hearsay witness; differences in whether mock jurors reached decisions individually or in groups; differences in the gender of mock jurors; differences in the nature of the experience leading to the declaration; different types of “crime”—whether theft, innocent touching, or sexual assault; differences in procedure—whether the hearsay witness (or declarant) was cross-examined; whether there was other evidence; and whether the evidence was presented by the state or the defense. However, it is not obvious that the experimental results are sufficiently consistent, coherent, or robust to provide a solid basis for drawing generalizations and conclusions justifying specific hearsay reforms with application to real world litigation.

Even where the studies do seem to identify potential problems with current rules and assumptions, as with the suggestibility of children or the recollection of interviewing techniques, questions remain about the precise implications for practice. Should we, for example, insist on recorded interviews with children at the earliest opportunity? If so, what happens when interviews are not recorded? Should we allow expert witnesses (e.g., the psychologists) to explain potential problems to fact-finders at trial? If so, should they be required to adhere strictly to the results of published studies or allowed to extrapolate? Should Daubert play a role? Would recourse to experimental psychologists as expert witnesses make any difference? And, how should the lengthening of trials, the added costs, and greater complexity in evidence (and judicial directions) be factored in?

Significantly, the “high degree of convergence” in empirical research as to the dangers of eyewitness testimony (Park and Saks, 2006 : 960) may be exceptional, as may be the relative clarity of the procedural prescriptions flowing from this research. Empirical legal studies often present as many questions as answers. And, proposals for law reform—such as additional judicial education—are often simplistic or naïve in political, sociological, and institutional terms.

C. Factual uncertainty and the benchmark problem

Evidence law is an institutionalized (and socially contingent) response to the inherent difficulty of arriving at an accurate version of past events. It is rare that the factual accuracy of inferences can be assessed, let alone the extent to which accuracy is advanced by particular evidentiary principles. Not insignificantly, DNA profiling, particularly when it provides the basis for exonerations, has enabled some verdicts to be benchmarked against the accused's actual innocence. Regrettably, interventions by Innocence Projects give criminal justice systems few grounds for complacency. Many wrongful convictions had, prior to DNA-based exoneration, survived multiple appeals and re-trials.

The benchmarking issue also arises for empirical researchers seeking to assess the epistemic value of an evidentiary rule, type of evidence or verdict. A number of the studies sought to draw normative conclusions about the accuracy with which human fact-finders handled particular types of evidence. The earlier hearsay studies concluded that mock jurors appropriately discounted hearsay evidence. Yet, in most of the experiments the “accuracy” of the hearsay evidence was unknown and unknowable—there was no benchmark, as the ultimate factual question was fictitious. Some investigators sought to respond to this issue by basing their experiment on real events. One study, for example, began with the staging of the actual event—an adult touching (or not touching) a child (Goodman et al., 2006 ). For obvious reasons, there are limits to the degree of realism that can be introduced to such experiments.

Some of the accounts of human inference have looked to Bayesian probability theory rather than objective fact as a benchmark. The H&B researchers, in particular, labeled departure from the calculus of probability, and Bayes's Theorem in particular, as a “bias.” Wells and others, in conducting their subjective probability experiments, were more concerned with developing a descriptive model. However, their work, revealing a similar departure, also implies that human reasoning in conditions of uncertainty is suboptimal. Perhaps there is a role for evidence law to intervene and address empirically-identified biases (Saks and Kidd, 1980 ).

An immediate difficulty with this proposal is that the Bayesian norm is highly contentious. Several legal commentators agree that “naked statistical evidence” provides an inadequate basis for liability. For them, a high probability figure must be supported by sufficient weight, detail and/or resilience (Stein, 2005 : 120; Ho, 2008 : 166). If a high base-rate probability is sufficient, what incentive is there to seek more specific evidence? And yet, subject to resource considerations, the enterprise of juridical proof is founded on the assumption that the more evidence the better. This preference underlies Benthamite criticisms of the exclusionary rules and, sometimes, their justifications. Recall that the hearsay rule can be rationalized on the basis that it increases the quality and quantity of evidence available to the fact-finder.

As noted in Section II, in recent decades Bentham's free-proof position has come to predominate, albeit indirectly. Daubert's tightening of admissibility requirements for expert evidence in civil proceedings represents something of an anomaly shaped by institutional pressures and socio-economic impressions and beliefs (more below).

D. Competing goals and values

A further issue arising from the empirical studies is the tendency to focus predominantly on the goal of factual accuracy. Prescriptions derived from the studies may provide benefits in this particular area, but these need to be weighed against potential costs elsewhere. Factual accuracy may be the primary goal of evidence law, but it is certainly not the only goal (e.g., Twining, 2006 : 76; Ho, 2008 : 339). Rules dealing with the dangers of eyewitness evidence may fall fairly squarely under the accuracy heading, but principle may implicate other goals. Depriving the fact-finder of probative evidence, via the hearsay rule may, on balance, be preferable to denying the opposing party the right to confront an accuser. The remoteness and lack of detail of hearsay or naked statistical evidence may make verdicts reliant upon them unfocused and impersonal, and hinder the effective expression of norms. A verdict based upon inaccessible or incomprehensible expert opinion may present similar problems.

It may be that the primacy of factual accuracy is such that many of these arguments can ultimately be dismissed. Our point, however, is that they cannot be ignored or disregarded altogether because concern about factual accuracy underpins only some of the goals, values and assumptions shaping rules of evidence and legal practice.

E. Bigger pictures

Empirical research and attendant legal reform should be sensitive to broader socio-political considerations and theory. STS perspectives, for example, may help to expand the focus from rules, processes and simplistic images of expertise to interests, institutions and social processes.

The majority in Daubert , for instance, supported its first criterion with reference to the work of Popper and Carl Hempel. The juxtaposition of these two irreconcilable philosophical accounts, and their eclectic combination with other, more sociological criteria (e.g., peer review and general acceptance), not only renders the Supreme Court's philosophical understanding open to doubt, but raises questions about the epistemological legitimacy of its admissibility jurisprudence (Haack, 2001 ). Yet, in their survey of judicial understanding of Daubert , Gatowski et al. based their assessments on folk versions of falsifiability and abstract questions rather than studying what judges in situ actually do. In Figure 4 the lines between understanding, misunderstanding and uncertainty are not merely blurred but conceptually suspect. Judicial responses to a survey instrument were assessed against idealized, and philosophically inflected, representations of science rather than empirical studies of actual scientific practice (see also Freckelton et al., 1999 ; cf. Edmond, 2005 ).

STS perspectives encourage us to ask: If Daubert does not represent a neutral vision of science, why were the particular criteria favored? And, are the criteria well suited to determining the admissibility of expert evidence in civil and criminal proceedings? Answers to such questions might help us to understand why Daubert and “gate-keeping” seem to have achieved such symbolic significance even though their conceptualizations of science and expertise appear simplistic, philosophically flawed and under-utilized.

One way to interpret the Supreme Court's admissibility jurisprudence is as a response to perceived problems with civil litigation, especially litigation “explosions,” “junk science,” excessive damages awards, and resulting deleterious economic effects (Haltom and McCann, 2004 ). Vigorous gate-keeping is a less overtly political intervention than changes to substantive tort or product liability laws and policies. Daubert provided judges with a means of regulating civil claims deemed “unworthy,” ideologically as much as factually, while publicly affirming their commitment to factual accuracy, the Seventh Amendment and the rule of law (Finley, 1999 ).

This more speculative reading of Daubert also brings trends in the criminal sphere into sharper relief. Trial and appellate judges have been relatively unresponsive to defense attempts to impugn incriminating scientific evidence. Expert evidence favoring the compensation of plaintiffs has been held to higher standards than forensic science evidence implicating defendants in criminal activities. This seems to reflect, directly and/or indirectly, socio-economic, and ideological concerns about excessive litigation as well, as the perceived need for more severe crime control.

There is obvious value in trying to integrate quantitative studies, and even surveys, into a more hermeneutic synthesis. These kinds of meta-analyses, while tentative and controvertible, generate new understandings and testable theories as well as questions about current practice and reform. They suggest, for example, that improving judicial scientific literacy might not be particularly effective. Confronted with a civil justice system purportedly “in crisis,” U.S. judges would probably have operationalized any admissibility standard more aggressively. If we reflect on admissibility trends (recall Figure 2 ) we find that in civil cases federal judges began to exclude expert evidence more proactively before Daubert , and practice in Frye jurisdictions was almost indistinguishable.

More critical approaches to expertise help to release scholars from slavish adherence to the descriptively dubious Daubert criteria, as well as polemical concepts like “junk science.” STS-inflected approaches allow for admissibility criteria to be indexed to the kinds of principles, values, and outcomes to which particular institutions and societies aspire. If, for example, we claim to value the presumption of innocence, fairness, and factual accuracy, then we should be more interested in the reliability of forensic science techniques. Rather than disguising our policy-political preferences in terms of appeals to purportedly proper definitions of science, demonizing the evidence of opponents as “junk science” or invoking long-standing practice (as with fingerprint evidence), it might be preferable to formulate strategic models of science and expertise based on explicit policy preferences and principle.

V. Rationalist and Empiricist Legacies

Most of those operating in the rationalist tradition have invoked or exploited the experiential and pragmatic nature of evidence and evidence law, though without much engagement or interest in empirical study. This is almost as true of legal scholars as it is of legal practitioners and judges (Park, 2003 ). Years spent in legal practice (or scholarship), so it is thought, gives practitioners and judges privileged exposure to both the real world and human nature .

While it might be fair to say that many of the contributions from empirical legal studies are provisional and their precise value for practice is uncertain or ambiguous, it would be equally unfair to suggest that they did not raise important issues worthy of serious consideration (Park and Saks, 2006 ). Moreover, by identifying problems with eyewitness evidence and the limitations of many of the forensic sciences, and in many other ways, empirical and experimental studies have substantially outpaced and repeatedly embarrassed legal experience . Nevertheless, in most jurisdictions judges have responded even to mature research traditions at best superficially and, at worst, with disdain shored up by complacent reference to collective experience or legal exceptionalism.

The obdurate indifference of lawyers, judges and policy-makers to empirical research on evidence law seems misguided (Leiter and Allen, 2001 ). It is difficult to know how to promote more principled and empirically calibrated approaches to evidence and proof. One response might be to encourage the most attentive and influential legal practitioners to participate in qualitative and quantitative forms of inquiry. The complexity and diversity of legal practice, along with its relative inaccessibility, makes multi-disciplinary investigation with research teams composed of empirical scholars and theorists, as well as lawyers and judges, a potentially productive, if practically and methodologically awkward, means of facilitating relevant real world research with direct bearing on practice (Edmond et al., 2009 ). It might also serve to remind us that law reform and empirical research should be related and ongoing.

Sir Francis Bacon (1561–1626), an early proponent of experimental natural philosophy and sometime Lord Chancellor of England, reputedly died from pneumonia after endeavoring to preserve the flesh of fowls with snow. Most of those involved with evidence law, particularly our lawyers, judges, and evidence scholars, seem to have taken more from Bacon's empirically induced fate than from his experimentally oriented philosophy. Perhaps ironically, commitment to legal experience places modern Anglo-American judges in a position similar to the Aristotelian schoolmen Bacon railed against. Unabated, indifference to empirical legal study is likely to reduce the social legitimacy of our legal institutions and undermine the fairness and accuracy of their rules, processes, and results.

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Introduction to Theory of Legal Evidence - Evidence in Legal Theory

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• Maciej Dybowski   ORCID: orcid.org/0000-0002-8699-1292 24 &
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The volume “Theory of Legal Evidence: Evidence in Legal Theory” deals with theoretical and philosophical problems of legal evidence. The concept of evidence is expected to fill a number of distinct roles in science, philosophy, but also in legal theory and law. Some of these roles are complementary, while others stand in tension or have little in common. The title of this volume suggests two types of problems. Chapters authored by legal theorists experienced in different legal cultures, including Europe, but also Latin America and the United States, address those problems and the need for an interdisciplinary approach to the study of standards of proof and evidence-taking in law. This interdisciplinary approach is put to work in the present volume with regard to two specific dimensions of integration of legal scholarship. First, the authors differ in their theoretical profiles and methodologies but share the interdisciplinary and externally-integrating view of legal scholarship, calling for the inclusion of social sciences and humanities in order to grasp the complex picture of law in action, and evidence functioning within it. Second, the contributors track down the problem of evidence within argumentation and thinking of legislators, judges, lawyers and legal scholars as calling for a side by side internal integration of legal sciences, which has to do with rethinking the strengths and weaknesses of ‘the new evidence scholarship' movement. The chapters are ordered in such a way that they start with more general and theoretical ones questions, zooming in to more specific theoretical questions put in context with philosophical concepts, and finally end with practical questions of legal evidence as they occur during legal proceedings.

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Dybowski, M., Klappstein, V. (2021). Introduction to Theory of Legal Evidence - Evidence in Legal Theory. In: Klappstein, V., Dybowski, M. (eds) Theory of Legal Evidence - Evidence in Legal Theory. Law and Philosophy Library, vol 138. Springer, Cham. https://doi.org/10.1007/978-3-030-83841-6_1

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Theorising Evidence Law

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• PMCID: PMC10550279
• DOI: 10.1093/ojls/gqad007

What does it mean for a specialist department of legal studies, such as the Law of Evidence, to have, or to acquire, 'philosophical foundations'? In what sense are the theoretical foundations of procedural scholarship and teaching distinctively or uniquely philosophical ? The publication of Philosophical Foundations of Evidence Law (OUP, 2021), edited by Christian Dahlman, Alex Stein and Giovanni Tuzet, presents a valuable opportunity to reflect on these existential questions of disciplinary constitution, methodology and design. This review article critically examines the volume's idiosyncratic selection of topics, structural taxonomy, epistemological priorities, and enigmatic thesis that modern evidence law is turning from rules to reasons as its organising intellectual framework. Whilst the volume is impressively interdisciplinary and cosmopolitan in authorship and outlook, some doubts are expressed about its implicit US orientation, limited engagement with institutional or doctrinal details, and marginalisation of normative criminal jurisprudence.

Keywords: criminal jurisprudence; evidence and proof; evidence law; philosophical foundations.

© The Author(s) 2023. Published by Oxford University Press.

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The law of Evidence regulates the presentation of factual information in the Anglo-American jury trial process and legitimates the outcomes of that process. In a wider sense, the concept of evidence embraces the process of proof of facts in any legal proceeding.

In this course, evidence law is presented and studied in the context of American trial advocacy with some comparative perspectives on fact-finding in various legal systems and before various administrative and arbitral tribunals. The course is structured around the Federal Rules of Evidence but also includes evidence issues from other sources. The basic topics of relevance, hearsay, form of direct and cross examination, rules of exclusion, illustrative aids, impeachment, authenticity, expert testimony, best evidence, privilege, and unfair prejudice will be covered through study and discussion of trial problems as well as of rules and cases. The course also includes computer-aided video exercises in simulated trial settings.

Assignments will be posted on the course Canvas site each week. Students will be expected to be prepared to participate in class discussion and solution of the assigned problems.

Evidence is a recommended prerequisite for the Trial Advocacy Workshop and can support certification for student practice in the Law School’s clinical offerings.

Text: The course text, problems, lecture notes, assignments, and additional materials will all be available electronically through the course Canvas site. Most of the materials are also available in Green, Nesson and Murray, Problems, Cases and Materials on Evidence, 4th Ed. (Aspen 2018). The problems that will be assigned are also available in print in Green, Nesson & Murray, Problems in Evidence. A current paperback copy of the restyled Federal Rules of Evidence will also be a convenience.

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While Sandel argues that pursuing perfection through genetic engineering would decrease our sense of humility, he claims that the sense of solidarity we would lose is also important.

This thesis summarizes several points in Sandel’s argument, but it does not make a claim about how we should understand his argument. A reader who read Sandel’s argument would not also need to read an essay based on this descriptive thesis.  

Broad thesis (arguable, but difficult to support with evidence) 

Michael Sandel’s arguments about genetic engineering do not take into consideration all the relevant issues.

This is an arguable claim because it would be possible to argue against it by saying that Michael Sandel’s arguments do take all of the relevant issues into consideration. But the claim is too broad. Because the thesis does not specify which “issues” it is focused on—or why it matters if they are considered—readers won’t know what the rest of the essay will argue, and the writer won’t know what to focus on. If there is a particular issue that Sandel does not address, then a more specific version of the thesis would include that issue—hand an explanation of why it is important.  

Arguable thesis with analytical claim 

While Sandel argues persuasively that our instinct to “remake” (54) ourselves into something ever more perfect is a problem, his belief that we can always draw a line between what is medically necessary and what makes us simply “better than well” (51) is less convincing.

This is an arguable analytical claim. To argue for this claim, the essay writer will need to show how evidence from the article itself points to this interpretation. It’s also a reasonable scope for a thesis because it can be supported with evidence available in the text and is neither too broad nor too narrow.  

Arguable thesis with normative claim 

Given Sandel’s argument against genetic enhancement, we should not allow parents to decide on using Human Growth Hormone for their children.

This thesis tells us what we should do about a particular issue discussed in Sandel’s article, but it does not tell us how we should understand Sandel’s argument.  

Questions to ask about your thesis 

• Is the thesis truly arguable? Does it speak to a genuine dilemma in the source, or would most readers automatically agree with it?  
• Is the thesis too obvious? Again, would most or all readers agree with it without needing to see your argument?  
• Is the thesis complex enough to require a whole essay's worth of argument?  
• Is the thesis supportable with evidence from the text rather than with generalizations or outside research?  
• Would anyone want to read a paper in which this thesis was developed? That is, can you explain what this paper is adding to our understanding of a problem, question, or topic?
• picture_as_pdf Thesis

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• v.120(41); 2023 Oct 10
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Science, Evidence, Law, and Justice

A scientist’s take on scientific evidence in the courtroom, thomas d. albright.

a The Salk Institute for Biological Studies, La Jolla, CA 92037

Associated Data

There are no data underlying this work.

Scientific evidence is frequently offered to answer questions of fact in a court of law. DNA genotyping may link a suspect to a homicide. Receptor binding assays and behavioral toxicology may testify to the teratogenic effects of bug repellant. As for any use of science to inform fateful decisions, the immediate question raised is one of credibility: Is the evidence a product of valid methods? Are results accurate and reproducible? While the rigorous criteria of modern science seem a natural model for this evaluation, there are features unique to the courtroom that make the decision process scarcely recognizable by normal standards of scientific investigation. First, much science lies beyond the ken of those who must decide; outside “experts” must be called upon to advise. Second, questions of fact demand immediate resolution; decisions must be based on the science of the day. Third, in contrast to the generative adversarial process of scientific investigation, which yields successive approximations to the truth, the truth-seeking strategy of American courts is terminally adversarial, which risks fracturing knowledge along lines of discord. Wary of threats to credibility, courts have adopted formal rules for determining whether scientific testimony is trustworthy. Here, I consider the effectiveness of these rules and explore tension between the scientists’ ideal that momentous decisions should be based upon the highest standards of evidence and the practical reality that those standards are difficult to meet. Justice lies in carefully crafted compromise that benefits from robust bonds between science and law.

                         ‘Bridgeport?’ said I. ‘Camelot,’ said he.

                                 Mark Twain ( 1 ).

Science and law have long intertwined roots as disciplines commonly devoted to rational choice. Legislative and executive branches of our government routinely turn to scientific discoveries to guide the development of laws, policies, and regulations to serve and protect members of society. Similarly, our courts rely heavily upon scientific knowledge to make informed decisions about disputes over matters such as ownership, causality, and responsibility. In this essay, I focus on the role of science in courtroom litigation, as this is the area of law that places the greatest demands on scientific evidence.

I acknowledge at the outset that this is not new ground, but it is ground infrequently traveled by laboratory scientists. The complex and sometimes contentious relationship between science and law is the subject of countless law review articles and amicus briefs, not to mention a comprehensive five-volume treatise by law professors ( 2 ). Prominent institutions of science long ago trumpeted the standards of science as a natural model for evaluation of scientific evidence by the courts:

“The scientific community’s well-established criteria and institutional mechanisms for evaluating the validity of scientific assertions provide courts with clear and understandable guidance on how they can rationally and consistently evaluate scientific evidence. Courts should admit scientific evidence only if it conforms to scientific standards and is derived from methods that are generally accepted by the scientific community as valid and reliable ( 3 ).”

Though this counsel serves as an ideal, much of the landscape of the scientific enterprise familiar to most practitioners—a “generative adversarial” process that yields ever-growing knowledge and certainty—is distorted or compromised by the “terminal adversarial” approach to truth employed by our courts. In the following discussions, I introduce a number of issues that arise from this particular use of science. Some of these are shared generally—or at least superficially—with the practice of scientific research, including assessment of the trustworthiness of evidence, the degree to which it reflects the consensus of the day, and the probability that it provides a correct solution to a problem in the real world. Other issues are unique to the legal context, including the procedure by which evidence is communicated to the court, and the exigence and resoluteness of decisions. My goal is to highlight areas at the intersection of science and courtroom law that raise interesting and sometimes unresolved questions—particularly when seen from the perspective of the scientific community—and would benefit from greater interdisciplinary collaboration.

Specialized Knowledge in the Courtroom

Scientific investigation and courtroom litigation have many notable differences in concept, history, and procedure ( 4 , 5 ), but they both operate through a process of “drawing inferences from evidence to test hypotheses and justify conclusions” ( 6 ). Because evidence is the crux of rational decisions, both disciplines have adopted standards to establish its trustworthiness. In the sciences, those standards are defined by the scientific method and policed by peer review, which ensures that evidence is based on valid methods and is carefully interpreted to develop and test hypotheses, advance theoretical perspectives, and inspire sound inventions.

Analogously, our justice system is a recipient of evidence from many sources intended to support one or another hypothesis before the court. The diversity of evidence received means that it may, or may not, fall within the common experience of the trier of fact. In some cases, the interpretation of evidence is patently obvious (the weapon was in the suspect’s bag), but in other cases (the shampoo contains a carcinogen), additional technical information is needed to guide the trier of fact ( 7 ). That guidance is generally provided by an expert witness whose “scientific, technical, or other specialized knowledge” will help the judge or jury understand the evidence. The court’s use of this expert approach is defined by a series of rulings and legislative actions that impose quality standards for admission of evidence, the primary goal of which is to ensure that the information is trustworthy. The trial judge is the designated “gatekeeper,” who oversees the evaluation of expert testimony in the context of existing rules ( 8 ), ultimately determining whether it can be used as a sound basis for probabilistic inference.

In many instances, the expert is someone who has gained subject-matter expertise through unique first-hand experiences in a particular knowledge domain. Suppose, for example, that the court wishes to determine who is at fault for a ship collision in the harbor. The testimony of a skilled tugboat captain might serve as evidence for this determination, as she is likely to possess accurate information about the probabilities of relevant events. This expert testimony may come in the form of a diagnosis (the larger ship’s pilot failed to see the smaller vessel), or it may come as a thesis on navigational principles [“framework testimony” ( 9 , 10 )], which the jury can apply to facts of the case. Either way, the question of admissibility is straightforward because the subject-matter expert is an embodiment of the evidence acquired through her own personal experience guiding massive watercraft through tight spaces. The same logic holds for dry cleaners, foresters, and taxi drivers, or any other individual who possesses a desired type of specialized knowledge acquired through personal experience.

Uses of Scientific Knowledge in Courtroom Litigation

Fueled by the expansive growth of science over the past century, scientific investigation and courtroom litigation now commonly converge: Scientific evidence is brought before the court to help resolve questions of fact. Broadly considered, those questions are of four types, which science is generally well equipped to address:

1) Who broke the law?

This is the forensic question, in which a science-based reconstruction of events is used to determine human responsibility for a criminal act. A valid demonstration that DNA found at a crime scene has a high probability of association with a suspect is a common form of scientific evidence introduced in litigation.

2) Who is liable for loss or harm?

Determinations of causality and responsibility are the focus of tort law, in which science may be used to argue that an act of negligence or intent by one party, or a product (e.g., a machine or a chemical) that one party is responsible for, was the cause of loss or harm to another. A demonstration that chemicals introduced into drinking water cause disease is a form of scientific evidence introduced in civil litigation to prove liability ( 11 ).

3) What will happen?

Proposed actions or products may be seen as legal rights of one party, while another party maintains that those actions/products are a potential cause for loss or harm. Here, scientific evidence is introduced to make predictions about the future—to identify causal links and probabilities of things that have not yet happened—and the proposed actions/products enjoined or permitted by a civil court ruling. For example, a home developer that plans to alter the topography of its acreage may be prevented from doing so if the science of hydrology predicts a high probability of water damage to the adjacent property of another party.

4) Is it new?

This is the question of patent law. Because patented inventions are often based on scientific principles and technologies, scientific evidence introduced in litigation can be essential for resolving disputes over novelty. This use of science is different from the others in that its purpose is to establish what an invention is, rather than what happened, what was the cause, and who is responsible.

The Unique Status of Scientific Evidence in the Courtroom

Scientific evidence in the courtroom faces two significant challenges that are less common in other basic research or applied contexts:

1) The courtroom “user” of scientific evidence lacks understanding or experience

Unlike physicians and engineers – users of scientific evidence who are educated in scientific methods and principles – those who make decisions in the courtroom based on scientific evidence commonly lack knowledge in the relevant domains. Judges are generalists and juries are routinely composed of laypeople without scientific training. As for other forms of specialized knowledge, scientific experts may be sought to inform the court. There are, however, unique features of science that place unusual demands on an expert.

Science has evolved significantly over the past 200 y, acquiring and refining along the way a treasured set of methods and criteria for controlled investigation of natural phenomena in the search for knowledge. The uniqueness and sophistication of this enterprise, its rigorous requirements for quantification and reproducibility, its intolerance of fraud, and the transparency of the historical record are all characteristics that set scientific research apart from other professions. Scientific evidence is not restricted to the experience of any particular individual; it is drawn from a foundational well of knowledge that is continually deepening and maturing. The scholarly journals of modern science are rich repositories of this knowledge, which has become the basis for decision in many practical ventures, such as medicine and engineering. Because aspects of this science frequently exist outside the realm of experience for courtroom users of the information, the desired role of the expert is to communicate science in plain language to educate the jury. But the scientific expert, unlike the tugboat captain, is not intrinsically the source of that information.

2) The question demands immediate resolution

The truth-seeking strategies of scientific investigation and courtroom litigation are both founded on competition and rigorous debate of alternative theories. In practice, however, these adversarial systems operate by fundamentally different rules. Basic science advances through a generative adversarial system, in which disagreement generates testable hypotheses and new discoveries, which can help discriminate between adversarial positions. The result is a progressive accumulation and refinement of knowledge. Law, by contrast, relies upon a terminal adversarial system. Parties in litigation cannot resolve disagreements about cause and effect through further experimentation, as bench scientists might. The battle must be won through existing facts and argument alone. *

The problem with the terminal approach is epistemological, at least in part, for it is sometimes difficult to recognize scientific truth. And yet truth – and not just any truth, but today’s truth – is called for to answer a question of fact. † Karl Popper noted that science risks an “infinite regress” of hypotheses to be falsified, betraying the ephemeral nature of scientific conclusions ( 12 ). But Popper also spoke of a “basic statement” that could be made following any empirical test along this path:

• “Every test of a theory, whether resulting in its corroboration or falsification, must stop at some basic statement or other which we decide to accept … We simply stop when we are satisfied that the piles are firm enough to carry the structure, at least for the time being.”

Scientific evidence presented in litigation may meet Popper’s definition of a basic statement, but the needling question for the gatekeeping judge is always whether the “piles are firm enough to carry the structure.” Ever the pragmatist, Popper concluded that the answer can only be assessed as the “degree of corroboration,” measured not simply by the number of tests but also by “the severity of tests to which a theory has been subjected, and the manner in which it has passed these tests, or failed them” (emphasis in original). In practice, corroboration is what yields consensus within the scientific community. The reason that consensus is important can be traced to two fundamental limits of measurement: uncertainty and bias. Leaving aside willful misrepresentation, these are the core reasons why scientific evidence may not be trustworthy. In scientific research, uncertainty and bias are mitigated by empirical validation and reproducibility of results. Validation is the footing for any legitimate application of science because it offers a probabilistic estimate of the accuracy of a measured quantity. To be considered a credible basis for action, however, findings must also be reproducible under different conditions and in the hands of different investigators – yielding a state that Popper termed “intersubjective agreement.” (In simple statistical terms, detection of the same signal by two independent sensors, rather than one, indicates greater likelihood that the signal is real).

In the absence of corroboration, a basic statement presented as scientific evidence simply lacks the empirical support needed to justify a decision. This is a sensible threshold in the practice of scientific investigation, where additional experiments can be performed and alternative hypotheses can be developed and tested, but it hobbles the practice of courtroom litigation where claims can only be vetted by today’s science. Instead, to satisfy fairness constraints, it is often argued that courts should adopt a liberal approach to the admissibility of scientific evidence, allowing jury appraisal of unorthodox views with the conviction that truth will emerge through the adversarial process ( 13 ). That conviction may be accurate, but the more difficult situation is when two different scientific interpretations seem plausible and both have significant acolytes, opening the courtroom gate to competing versions of the truth. Generative adversarial science may sort this out eventually, but the terminal approach requires different strategies to limit adverse consequences.

Before considering those strategies, I first summarize current rules for admissibility of scientific evidence to the courtroom, trace how they originated and evolved, and examine how the professions of science and law can collaboratively ensure that courtroom decisions are based on information that can be trusted. Because these topics are deeply embedded in the Law of Evidence, I begin with a brief review of that doctrine.

The Law of Evidence

The jury system that is a central component of common law was initially based on the belief that members of the community could be self-informed about a local contest and thus serve as both experts and decision-makers ( 14 , 15 ). All of this changed in the 18th century with the emergence of the Law of Evidence, which understood that complex forms of probative knowledge are often beyond the ken of community jurors. From this understanding emerged two important principles:

• 1. Jurors should be chosen not for their communal familiarity with contested events but, rather, as blank slates who might be persuaded by credible evidence.
• 2. Not all evidence is equally credible, requiring that standards be adopted for use.

This transition initiated the instructional approach to jury decisions, in which subject-matter experts are employed to inform juries of the intricacies, context, and meaning of evidence for which they lack the native wisdom and experience to comprehend.

In the early days of this practice, experts were called upon to explain evidence regarding the provenance or authenticity of documents, as, for example, in cases of patrimony or trespass, or to provide medical testimony as to the cause of death ( 14 ). Admission of such expert testimony was initially based on informal demonstrations that a) the testimony was relevant and would facilitate jurors’ understanding of complex knowledge ( 16 ), “which laymen could not be expected to comprehend and properly estimate” ( 17 ), and b) the expert was qualified by education and profession ( 18 ). The 19th and 20th centuries saw rapid growth of science and with that came a dramatic increase in the complexity of evidence before the court ( 19 , 20 ). And so it was that experts from the sciences – physicists, anthropologists, chemists, and biologists – were summoned to opine on probabilities that past events happened as charged or to advise on the likelihood that a faulty machine or toxic substance was the cause of injury ( 21 ). Doing so poses a risk, however, that an expert may not have sufficient grasp of the science, may intentionally misrepresent the facts, or that the science itself may not be sufficiently established or relevant. Wary of this threat, the courts began to consider more formal strategies for determining whether scientific testimony is sufficiently trustworthy that it should be presented to the trier of fact.

Because the vehicle for conveying expert legal testimony is the human mind, it seemed natural to look there for the answer. The academic discipline of psychology – the science of mind – sprouted in the mid-19th century from roots in physiology, physics, and philosophy. By the turn of the 20th century, experimental psychology seemed on the cusp of revealing the causes of perception, cognition, and behavior ( 22 ). Together with new tools for assessment of nervous system function, psychology promised no less than a full reasoned account of human experience, which would have enormous potential for explaining human decisions in the real world. One of the earliest applications of this new psychology was an assessment of perception and cognition in the context of courtroom decisions, from which a so-called “legal psychology” was born ( 23 ). From this auspicious brew emerged the hypothesis that certain measures of brain function might be indicia of deceit, which could be used for assessment of the validity of legal testimony. One of these measures, a precursor to the modern-day polygraph (“lie detector”) test, now lives in legal infamy as the trigger for the first major federal court ruling on admissibility of scientific evidence. ‡

The Frye Standard for Admission of Scientific Evidence

The first major ruling to effect standards for scientific evidence in the American justice system was handed down one hundred years ago by the US Court of Appeals for the DC Circuit in Frye v. United States ( 24 ). § James Frye, a twenty-something-year-old resident of the District of Columbia, was questioned regarding the murder of a prominent Washington physician, Robert Brown. Frye confessed to killing Brown accidentally in dispute over payment and was charged with first-degree murder. By the time of his trial in district court, Frye had recanted. His legal defense team had meanwhile recruited the assistance of William Marston, a Harvard-trained psychologist. ¶ Marston claimed that he could detect deception through changes in systolic blood pressure, elicited by arousal of the autonomic nervous system. Based on laboratory results from this new technique, Marston argued that Frye’s innocence was proved. Skeptical of the scientific foundations and in the absence of “common knowledge” of the method’s validity, the trial court refused to admit testimony based on Marston’s tool (“we do not bring experimental matters into court”) ( 25 ). Frye was convicted of the lesser charge of second-degree murder and sentenced to life in prison.

James Frye’s appeal was based on the argument that Marston’s blood pressure machine was indeed a legitimate scientific instrument for assessment of deception. The appeal was heard by the DC Circuit, which sustained the lower court’s ruling that the instrument had not been sufficiently validated:

• “We think the systolic blood pressure deception test has not yet gained such standing and scientific recognition among physiological and psychological authorities as would justify the courts in admitting expert testimony deduced from the discovery, development, and experiments thus far made.”

In doing so, the appellate court issued a ruling in 1923 – a ruling nearly as notable for its brevity (669 words) as for its impact (it is among the most heavily cited rulings in American case law) – that ultimately established an admissibility test for scientific evidence. Known today as the “ Frye standard,” the test was increasingly applied in US Courts for the next seven decades and adopted (and still used) in many state courts as well:

• “Just when a scientific principle or discovery crosses the line between the experimental and demonstrable stages is difficult to define. Somewhere in this twilight zone the evidential force of the principle must be recognized, and while courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle or discovery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs .” (emphasis added)

Sufficient evidence that the lie detector yielded accurate results simply did not exist, meaning that “the thing from which the deduction [James Frye’s innocence] was made” was neither shown to be valid nor “sufficiently established to have gained general acceptance.” The court thus found that Marston’s instrument remained on the darker side of the twilight zone, where “the evidential force of the principle” had not yet been recognized.

We see in Frye the beginnings of a legal formalization of common-sense criteria for the value of scientific evidence, which go well beyond the earlier “helpful” and “qualified” standards. Consider, for example, scientific evidence brought to show that fingerprints found at a crime scene were left there by a suspect in custody. This is evidence of some import. But as a practical matter, how might we know that it is a sound basis for choice? There are several standards common to the sciences for assessing evidence, which are born from laboratory tests conducted under ground-truth conditions:

• 1. The evidence is obtained using valid methods and is accurate.
• 2. The evidence is reliable and reproducible by others.
• 3. There is consensus that the evidence is a sound basis for decisions. Frye ’s “general acceptance” or consensus standard is based on the premise that a community of people with appropriate expertise could not have come to the same conclusion about the evidence unless the methods were valid and the results accurate, reliable, and reproducible.

Significant Features of the Frye Ruling

There are two significant features of Frye that point to the unique status of scientific evidence and the role of the expert:

• 1. The Frye concept of general acceptance is fundamental, as it aligns with Popper’s “degree of corroboration.” Legal theorist Steven Goldberg cited community and communal beliefs as the first of four “Central Dogmas of Law and Science:” “There is in modern America a scientific community capable of forming a consensus on technical matters” ( 26 ). Through a distributed process of self-government and policing, this community soundly rejects claims that do not satisfy requirements for validity, accuracy, and reliability. Considered abstractly, if we wish to inform consequential decisions with scientific knowledge, the consensus at any point in time is the most rational ground for doing so. But legal decisions never occur in a social or cultural vacuum; they must be ecumenical and tempered by fairness. All of which encourages flexibility but sets the stage for conflict in the courtroom.
• 2. The Frye ruling refers only to the character of the “scientific principle” proffered as evidence. Frye makes no mention of subject-matter expertise ( 27 ), except in the sense implied by the “general acceptance” clause, which refers to the consensual expertise held by the scientific community. This concept of consensual expertise as the basis for establishing trustworthiness became eroded through establishment of the Federal Rules of Evidence, which turned the focus toward opinions of individual experts.

Rule 702: Testimony by Experts

By the 1970s, a sense had emerged that the inflexible Frye requirement for general acceptance was difficult to establish and perhaps insufficient, in that it was mainly relevant to criminal cases in which an invented instrument was proposed to establish fact. # Partly in response to this concern, standards for admissibility of scientific evidence began to change. They did so initially, at least in a formal sense, following recommendations of a federal advisory committee of the United States Judicial Conference, which was established for the broader purpose of normalizing and codifying rules for the use of evidence in US Courts. The Federal Rules of Evidence became law in 1975 by act of Congress. The particular rule that bears on admissibility of expert testimony is known as Rule 702 ( 28 ).

While Frye selectively targets the use of scientific evidence, Rule 702 applies more generally to expert testimony on “scientific, technical, or other specialized knowledge,” meaning that the same standards apply to evidence drawn from the well of scientific knowledge and to subject-matter experts in nonscience knowledge domains, such as tugboat captaining. In its original form, Rule 702–1975 merely formalized and made into law standards for “helpfulness” and “expert” qualifications, both of which had been less formally applied since the 19th century:

• “If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise.”

As a notably limp standard for judging the evidentiary nuances of modern science, Rule 702-1975 was subsequently interpreted and clarified by the Supreme Court’s transformative 1993 ruling on scientific evidence in Daubert v. Merrell Dow Pharmaceuticals, Inc. ( 8 ).

The Daubert Standard

Unlike the forensic instrument that motivated the Frye standard, in which the question before the court concerned the scientific validity of measured quantities, the Daubert ruling emerged from a toxic tort case, in which scientific evidence attempted to establish cause and effect. Daubert’s civil action was filed against the drug company Merrell Dow Pharmaceuticals in 1984, on behalf of two children born with serious birth defects. The mothers had taken the drug Bendectin [doxylamine succinate and pyridoxine hydrochloride (vitamin B 6 )], which was manufactured by Merrell Dow and widely used for decades to quell nausea and vomiting during first-trimester pregnancy. The plaintiff alleged that Bendectin had caused deformities during gestation. Merrell Dow maintained that there was no scientific evidence of a link between their drug and birth defects, but Daubert recruited an expert in the form of obstetrician William McBride, who was prepared to testify on the teratogenic effects of Bendectin. Noting that McBride’s assertions failed to meet the Frye standard of general acceptance by the scientific community, the District Court for the Southern District of California issued summary judgement in favor of Merrell Dow ( 29 ). Daubert appealed to the Ninth Circuit, which upheld the lower court’s ruling ( 30 ).

In response, Daubert went on to argue before the Supreme Court that the common law Frye standard for admissibility of scientific evidence was inapplicable in their case, because it had been replaced in 1975 by the legislatively enacted Rule 702. The Court agreed and upheld Rule 702–1975 as the modern legal standard for admissibility in federal court, superseding the Frye standard. ‖ In its ruling ( 8 ), the Court provided an interpretation of Rule 702–1975, which is known today as the Daubert standard. This standard consists of a set of clear and useful criteria for assessing the trustworthiness of scientific evidence:

• • whether the theory or technique in question can be (and has been) tested,
• • whether it has been subjected to peer review and publication,
• • its known or potential error rate, and
• • the existence and maintenance of standards controlling its operation, and
• • whether it has attracted widespread acceptance within a relevant scientific community
• Unlike the uncompromising Frye standard, these criteria are intended to be flexibly applied at the discretion of the trial judge.

With these brief considerations, Daubert strengthened the application of evidence law in several ways that conform to the nature of scientific investigation. Perhaps most importantly, Daubert returned the focus to the body of scientific knowledge ( 27 ), highlighting the importance of empirically demonstrating [“can be (and has been) tested”] that a scientific instrument or principle is a valid predictor of the probability that a courtroom hypothesis is correct (“known or potential error rate”). To that end, the focus on widespread or general acceptance of scientific evidence – consistent with Frye but absent from Rule 702 – is notable here, as the scientific consensus at any moment is the rational basis for decision under the unyielding demands of courtroom litigation. Also consistent with Frye and contrary to the letter of Rule 702, Daubert emphasizes the need for evidence to reflect the consensus of the “relevant scientific community.” As highlighted below, the definition of relevance has become a battleground in efforts to reform the use of forensic evidence.

Rule 702 Evolves

Rule 702 was substantially amended in 2000 to conform with Daubert and to promote a “more rigorous and structured approach” ( 31 ), in which the gatekeeping role was formally handed to judges. The Rule’s emphasis on the expert remained, but three “reliability” requirements were included in Rule 702–2000 (provisions b-d), which place constraints on the data, methods, principles, and their application by the expert:

A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if:

• (a) the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue;
• (b) the testimony is based on sufficient facts or data;
• (c) the testimony is the product of reliable principles and methods; and
• (d) the expert has reliably applied the principles and methods to the facts of the case.

Rule 702 was revised again in 2022 (to take effect December 2023) through amendments proposed by the Advisory Committee on Evidence Rules and subsequently approved by the US Judicial Conference and the Supreme Court ( 32 ). For these efforts, Rule 702–2022 differs from the previous by two small text additions. One defines a preponderance of evidence (“more likely than not”) standard for demonstrating that the four provisions [702(a-d)] have been satisfied, which offers the gatekeeping judge a quantitative criterion for decisions about admissibility. The other clarifies that it is not the expert’s reliable application that matters, but rather that “the expert’s opinion reflects a reliable application,” which grants the trial judge the ability to bar opinions that exceed what can be reasonably concluded from the methods and principles applied.

In the following paragraphs, I discuss some of the strengths and weaknesses of the Rule, post Daubert , as seen in the light of evidence standards routinely employed by the scientific community.

• • Although Rule 702 promotes a healthy focus on the validity of scientific evidence, it turns the emphasis away from the Frye “general acceptance” standard and toward attributes of the expert. This partly reflects the fact that it was designed as a general-purpose rule for experts with specialized knowledge, not simply scientific experts. In doing so, however, the Rule fails to highlight scientific consensus, which is a primary determinant of trustworthiness. While consensus is appropriately recognized by Daubert via the “widespread acceptance” criterion, it should not be discretionary; consensus based on corroborative evidence is how we know things are true.
• • The introduction sets a loosely defined bar for qualifications of the expert. Lost from Frye , and failing to heed Daubert , is the requirement that the expertise arise from the relevant scientific community (“the particular field in which it belongs”). Although the relevant community is sometimes difficult to resolve from a viewpoint outside of the scientific enterprise, it would help to formally distinguish experts who opine on what a scientific instrument (or method, or test) does vs how well it works. **
• • 702a is the helpfulness criterion. Neither the introduction nor 702a speak to qualifications for the communication/education role of the expert, which is a prerequisite for helpfulness when conveying complex evidence. The focus should be placed on the expert’s ability to clearly communicate the relevant science to a lay audience. While parties may apply their own criteria for communication skills, the effect is sometimes obfuscation ( 33 ), which highlights the importance of courtroom standards.
• • 702b and 702c define attributes of the evidence itself that qualify it for admission. The emphasis on “sufficient facts or data” to support all facets of the expert’s testimony (702b) is critical to any rational decision based on scientific knowledge. Marston’s lie detector was excluded simply because there were very few facts or data to support claims of validity. The requirement that evidence be a “product of reliable principles and methods” (702c) is also critical. Evidence presented in support of a hypothesis should be empirically validated to reveal the probability that the hypothesis is true. Reproducibility—demonstration that evidence holds up across studies—is also important to overcome errors and biases that may be unique to a given study, and to gain consensus ( 12 ).
• • Finally, 702d is a requirement that expert opinions not exceed what is possible to conclude given the knowledge base and methods employed – the premise being that, once admitted, a lay jury may not be able to identify false or exaggerated conclusions drawn from complex evidence. Among the important targets of this provision is a tendency to generalize, without evidence, from scientific conclusions about group effects to conclusions about individual cases ( 10 ).

The positive impact of Daubert on the structure of Rule 702 cannot be overstated. It also continues to complement and clarify application of the Rule. Many courts today adopt a hybrid approach, in which the sensible standards of Daubert are used to bridge gaps in Rule 702. The problematic status of the “expert” nonetheless remains, with far-reaching implications for justice.

Are Experts Important?

I have argued that empirical demonstration of validity and reproducibility, and development of consensus within the relevant community, should be the primary criteria for admissibility of scientific evidence. Rule 702 nonetheless specifies criteria based on an expert’s scientific bona fides and ability to assist the trier of fact. This distinction raises an interesting empirical question: What is more persuasive to the trier of fact, the quality of the science or the attributes of the expert? Recent evidence suggests the latter ( 34 ). One might write a timely thesis on the cultural prominence of person over fact, but this is the common law system we live with today. Here, I discuss other attributes of experts and their potential impact on the justice system in which they serve.

Who Gets to be an Expert?

The “general acceptance” clause in Frye maintains that conclusions about consensus on a specific principle or discovery must be drawn from “the particular field in which it belongs.” The “widespread acceptance” clause in Daubert similarly states that acceptance must exist “within a relevant scientific community.” While it would be hard to argue against these directives, a persistent sticky point has been: What is the relevant scientific community? ( 35 ).

Distinctions between scientific disciplines are not in question here. The opinions of a herpetologist are scarcely relevant to fingerprint analysis. But there is a different way of parsing expertise that comes up frequently in applied sciences: the distinction between a researcher and a practitioner of scientific principles and techniques. The researcher is, by definition, the person involved in scientific experimentation and discovery, who has acquired an understanding of scientific principles of relevance to a real-world problem. The practitioner is, by contrast, the person with knowledge of the prevalence and characteristics of a problem in the real world who employs science-based inventions to mitigate the problem. In medicine, for example, the researcher is a basic scientist who has discovered the ameliorative effects of a chemical compound, which is made into a drug. The practitioner is the physician who prescribes the drug to a clinical population.

Both practitioners and researchers have domain-specific knowledge that may inform the court in different ways. Consider, for example, the respective contributions of the researcher and practitioner to questions of forensic firearms identification. If the court wishes to know something about the physical process by which firearms leave marks on shell casings, or the method that is used by a forensic lab to locate and characterize such marks, then the forensic practitioner is the best person to consult. If, on the other hand, the court wishes to know how well a forensic process is performed, the best person to consult is a basic scientist with expertise in human factors that affect the validity of human sensory decisions ( 36 ). Justice may be better served by clarifying this distinction when considering admissibility of scientific evidence.

Terminal Adversaries, Partisan Experts, and the Fracturing of Scientific Knowledge

• “Our courts are confronted with a pervasive phenomenon that often approaches and sometimes crosses the line into the realm of scandal.” ( 37 )

In consideration of due process, the procedures for courtroom litigation in American common law permit each party to recruit their own experts to convey scientific evidence in support of their position. In some ideal world, perhaps, these experts would present complementary details around the scientific consensus of the day, which may be advisory of one path or another, much like getting a second opinion on a root canal, or how to best repair the truck. This system fails in the legal context, however, because the parties are in conflict over the outcome, which means that the scientific experts they hire bear commitments that may place them in conflict with the truth. The result is a proliferation of testimony tagged disparagingly as “junk science,” sometimes proffered with the intent to introduce uncertainty or obfuscate ( 33 ).

This is hardly a new observation ( 27 , 38 ). The case of Keegan v. Minneapolis & St. Louis Railroad , argued before the Minnesota Supreme Court over 120 y ago, followed from a successful civil action brought by the family of a traveling salesman who died of endocarditis following a fall from a transport carriage. That fall was precipitated by a road that was poorly maintained by the defendant. In trial court, the plaintiff and defendant presented dueling experts opining on the causal relationship between the injury and the terminal disease, which the jury was forced to reckon with for judgment. The Minnesota Court upheld the lower court’s ruling, and in its wisdom broadly condemned the pathology of our judicial system that fosters competing versions of scientific truth:

• “Experts are nowadays often the mere paid advocates or partisans of those who employ and pay them, as much so as the attorneys who conduct the suit. There is hardly anything, not palpably absurd on its face, that cannot now be proved by some so-called ‘experts ( 39 ).’”

This pathology certainly caught the attention of jurist Learned Hand, who famously wrote:

• “Enough has been said elsewhere as to the natural bias of one called in such matters to represent a single side and liberally paid to defend it. … The result is that the ordinary means successful to aid the jury in getting at the facts, aid, instead of that, in confusing them… How can the jury judge between two statements each founded upon an experience confessedly foreign in kind to their own?” ( 14 ).

Indeed, how can they? In her brilliant analysis of the role of science in legal matters, Sheila Jasanoff cut straight to the underlying problem of choice in this context:

• “the formal and adversarial style of regulatory decisionmaking highlights uncertainty, polarizes scientific opinion, and prevents efficient resolution of disputes about risk. Far from promoting consensus, knowledge fed into such a process risks being fractured along existing lines of discord” ( 40 ).

Substitute “courtroom litigation” for “regulatory decision-making” and “disputes about cause” for “disputes about risk,” and the statement precisely captures the dysfunction with scientific testimony in American courts. This problem is well recognized in many scholarly texts on legal policy, and often expressed with sarcasm: Trials are “increasingly similar to barking seal contests in which rival trainers compete to induce their teams of trained experts to make the most winsome noises” ( 37 ). The advisory committee for the Federal Rules of Evidence considers “the practice of shopping for experts” a “matter of deep concern” ( 41 ). More recently, this phenomenal splitting of expert testimony along party lines has shown up in experimental results as not simply an overt effort to support a client, but as an unconscious yet quantifiable shift in an expert’s opinions and interpretation of facts – “working for one side in an adversarial case causes some experts’ opinions to drift toward the party retaining their services” – a cognitive process known as “adversarial allegiance” ( 42 ).

This “matter of deep concern” is where the difference between generative and terminal adversarial systems hits home. Decision-making – in scientific research and in the courts – depends on the ability to evaluate the relative probabilities that different hypotheses are true, given the evidence at hand. In science, when evidence is equivocal we generate another empirical test with the belief that the new evidence gained will tip the scale.

In courtroom litigation, by contrast, we paint lipstick on the pig, because she’s all we’ll ever have. And in the process, we fall in love with her. This is not the rational approach to fateful decisions that any scientist would advocate. If the evidence appears equivocal and the process is ineludibly terminal, the smart thing is to take a much closer look at the evidence, not dress it up with partisan “experts.” Doing so necessarily requires a broader engaged collaboration between the courts and the scientific community. To that end, there are several strategies worth considering.

Duty to the Court?

One approach to this vexing problem would be to transfer duty of the expert from the parties to the court and shore up the process by which the court can determine that the expert is correctly channeling the scientific consensus. Following the recommendations of a UK commission empaneled in the 1990s by Lord Harry Woolf (later Chief Justice of England and Wales), which noted the obvious problem – “experts had become partisan advocates rather than neutral givers of opinion” ( 43 ) – the courts in England and Wales revised procedural rules. “The basic premise of these [new] rules is that the expert’s function is to help the court, not to advance the case of the side by whom he or she is paid” ( 43 ). By this astute argument, scientific experts are appointed either through mutual agreement of the parties or at the discretion of the court. Their duty is “owed to the court” and “overrides any obligation to the person from whom experts have received instructions or by whom they are paid” ( 44 ).

On the surface, this neutral advisory function is antithetical to the adversarial system of law practiced in the United States. But it does seem to work in other common law countries, and the pitfalls of adversarial allegiance undermine the credibility of our existing judicial system. The Federal Rules of Evidence do include a provision for court-appointed experts (Rule 706) ( 45 ), which has had some success in educating courts on scientific matters ( 46 ). The mechanism is rarely used, however, in part because it stands in awkward conflict with the adversarial process ( 47 ). That awkwardness stems from a courtroom culture that empowers a competitive marketing approach to decision-making – indeed, litigators express “a marked preference for retained experts” ( 48 ) – while neglecting the view that truth and fairness in the courtroom, and increased accuracy of decisions, can only come from deeper understanding of the evidence.

Recognizing Scientific Consensus.

Deeper understanding of evidence in this context requires impartial review and scrutiny to assess the probability that one or another hypothesis is true. In scientific investigation, this is the function of peer review. Many established journals with blind peer review have extremely high standards for publication and scientific work therein is commonly read and cited with high frequency. While this offers an approximation of scientific consensus, unexpected findings and minority views are sometimes shunned by this elite process and forced to publish in fringe journals, causing critics to argue that the system mainly supports the status quo ( 49 ). In Dauber t, the Supreme Court noted that petitioners and their amici expressed precisely this concern: “exclusion of ‘invalid’ evidence will sanction a stifling and repressive scientific orthodoxy and will be inimical to the search for truth.” Daubert maintains, furthermore, that “Publication…is not a sine qua non of admissibility; it does not necessarily correlate with reliability.” The scientific community, by contrast, adopts a probabilistic view, arguing that publication through peer review correlates with validity but does not guarantee it ( 50 ). Nonetheless, if we accept that science published in high-quality journals is not necessarily valid and, conversely, valid science does not always receive the publication status it is due, then how can our courts possibly identify science that is both valid and generally accepted? One solution is to adopt the strategy that the scientific community generally employs for decisions about funding, promotions, and research priorities, which is based on a broader deliberative and open review of relevant science.

Science Courts and Scientific Peer Review Panels?

To this end, a controversial and long-neglected ( 51 ) proposal is to form a “Science Court” in which scientific experts for the parties “direct their best arguments at each other and at a panel of sophisticated scientific judges” ( 52 ). The concept is that scientific judges are prepared, unlike a traditional judge, to vet complex scientific evidence, such that they can supply the trial court with “statements founded on that knowledge, which will provide defensible, credible, technical bases for urgent policy decisions.” In effect, the science court would serve as a gatekeeper for scientific expert testimony and would package the product of its review as the consensus of the time for use by the trial court. The concept is similar to use of standing scientific committees that inform decision-making by regulatory agencies. The science court idea does have its detractors, however, who note a) evaluation of science removed from the larger context of a legal case may fail to consider contraindications or practical limitations from the real world, and b) a standing science court places too much power in the hands of too few.

An attractive alternative exists in the form of ad hoc peer review panels, or Consensus Panels ( 53 ), of the sort commonly convened by funding agencies to evaluate specific areas of proposed scientific research. Rotating panels would be embedded within the evidentiary process and aim to identify the scientific consensus regarding expert testimonies from the parties and advise the trial judge, all within the same pre-trial hearing.

To ensure fairness, a science court or a science advisory panel must not preclude input from traditional partisan experts ( 54 ). These scientific review strategies are nonetheless likely to be beneficial because debate is overseen by scientific experts – not judges – who a) have no investment in the outcome, b) are qualified to zoom-in closely on the evidence, and (c) can call-out exaggeration of the relevant science, or generalization beyond the bounds of the underlying principles and methods. Practicing scientists will recognize this as the same peer review process that keeps scientific research in check by adjudicating claims in a search for knowledge and certainty. A related approach, known as concurrent expert testimony, or “hot tubbing,” encourages experts for the parties to work together and identify areas of agreement and dispute. However sensible this latter approach may seem, there is little evidence that it works to reduce adversarial allegiance, possibly because there is no oversight and moderation by an independent body of scientists ( 55 , 56 ).

Severing Partisan Ties Without Sinking the Ship.

Real adversarial allegiance in expert testimony, or suspicion of it on the part of the trier of fact, is heavily influenced by the act of retention ( 57 ). The alternatives considered above – duty to the court or the use of impartial scientific review panels – are promising precisely because they sever those partisan ties. But they are not free, either with respect to time or value of specialized knowledge. The expense must come from a source that has no investment in the outcome. In their current incarnations, our courts cannot afford this. But as a free society, we live by the principle of unrestricted access to unbiased information. Our modern movement toward “open science” – public access to the corpus of publicly funded science, uncontrolled by source and unvarnished by partisan interests – is a start. In the same spirit, scientific societies could adopt professional rules of conduct that promote awareness of ways in which science is used by the courts, discourage adversarial allegiance by their members, and encourage legal testimony that hews closely to the scientific consensus. Some professional societies, such as the American Psychological Association and the American Academy of Psychiatry and the Law, do have professional guidelines that apply to legal testimony. While these guidelines stress impartiality, their primary focus is on privacy.

A Path Forward: Cross-Pollinating Science and Law

The phenomenal growth of modern science and the demands placed on scientific evidence in courtroom litigation raise important questions about the definition of scientific truth and how to recognize it in “terminal” applications. These questions have been partially addressed by legislative and judicial actions, but there are still holes to be filled. Adversarial allegiance and polarization of scientific opinion on questions of fact are predictable and highly dysfunctional consequences of a free market approach to information in an end-of-days courtroom economy. Such crises can be avoided by greater consilience between the disciplines of science and law, and the establishment of close working relationships that are independent of the interests of parties seeking specific legal actions. To this end, it is useful to view law as an applied science, as it pertains to questions of fact. To illustrate the benefits of this perspective, consider medicine, which is one of the most successful applied sciences of our time. In the United States today, there is a highly regulated process for assessing the validity of drugs through clinical trials ( 58 ). This process ensures that fateful decisions about drug use are based on high standards of evidence, and it is successful at doing so because of the close intellectual partnership between scientists and physicians. Bad science in the courtroom could be mitigated by similar efforts to cultivate close working relationships between scientists and legal professionals.

Such efforts are not without precedent, as seen through the work of both governmental and independent commissions and task forces ( 59 , 60 , 61 ). Many academic institutions also now house thriving centers operating at the interface of science, legal policy, and practice. The Committee on Science, Technology, and Law (CSTL), of the National Academy of Sciences (NAS), is among the most successful advisory panels convened for this purpose. CSTL was conceived to address “the evergrowing need for the legal and scientific communities to work with each other on issues of importance to the nation. The need for a prominent forum for representatives of these communities to get to know each other, understand their cultures, and exchange ideas” ( 62 ). CSTL has overseen production of consensus reports on a range of topics at the intersection of science and law, including forensic science ( 60 ), eyewitness identification ( 63 ), and the highly valued Reference Manual on Scientific Evidence ( 64 ). CSTL’s products are a respected source of guidance and its process is a grass roots model for the larger science-law culture that we envision.

“The Law Desires Truth, but Realistically Settles for Justice and Fairness” ( 65 )

Despite our best efforts, there will always be tension between a) the scientists’ ideal that momentous decisions be based upon the highest standards of evidence, b) the practical reality that those standards are sometimes difficult to meet, or that relevant science does not exist, and c) our unassailable right to fairness. This tension is workable, in principle, through compromise, flexibility, and well-reasoned understanding of criteria for scientific truth, but it forms a leaky structure that is easily exploitable, particularly in our age of misinformation. The solution is to promote awareness and vigilance by all parties and to foster collaboration between gatekeeping judges and scientists. “As the knowledge of science and the procedures of law evolve, the need for this ‘cross-pollination’ becomes ever more necessary” ( 62 ).

Acknowledgments

The interpretation of evidence and its use as a guide for human decisions are topics central to the sciences of sensation, perception, and cognition, where my roots lie. I have applied elements of this background to law with the conviction that there are still important bridges to build. In doing so, I have benefitted greatly from education and inspiration provided by many colleagues long committed to justice reform. In particular, I am grateful to David Tatel and David Baltimore, former co-chairs of the NAS Committee on Science, Technology, and Law, and Anne-Marie Mazza, executive director of the committee, for encouraging me to write on the topic of scientific evidence. I thank Joe Cecil and Brandon Garrett for discussions of evidence law and feedback on earlier drafts. Preparation of this perspective was supported by the Conrad T. Prebys Endowed Chair at The Salk Institute for Biological Studies.

Author contributions

T.D.A. wrote the paper.

Competing interests

The author declares no competing interest.

This article is a PNAS Direct Submission.

* The exception is “litigation-generated science” in which a party commissions a scientific study to answer a question of fact raised in ongoing litigation. There are no coherent statistics on the frequency of this practice, but it is believed to be rare because of time and expense, and discouraged because outcomes are susceptible to bias.

† Many argue that the concept of a singular scientific truth is naïve. This existential argument is irrelevant to the court, where the question of truth is more mundane and probabilistic: What current information has the highest likelihood of yielding a correct judicial outcome?

‡ The fascinating backstory to this ruling, complete with subterfuge, intrigue and academic scandal, is well told by historian Jill Lepore ( 25 ).

§ In 1911, People v. Jennings (252 Ill. 534, 549, 96 N.E. 1077) allowed fingerprint evidence on grounds of general acceptance and qualified expertise. While this state court ruling ushered in the use of fingerprints in criminal trials, it did not have Frye ’s broader impact.

¶ The same William Marston who created Wonder Woman.

# Prior to the 1970s, which saw an increase in toxic tort claims, Frye had no appreciable role in civil litigation.

‖ The Frye standard remains in effect today in several state courts.

** A pervasive problem with some forms of forensic evidence, as discussed below.

Data, Materials, and Software Availability

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Jill Lepore

David woods kemper '41 professor of american history, harvard college professor, and affiliate professor of law.

Harvard University | History Department | Cambridge, MA 02138 | On sabbatical 2023-2024

The History of Evidence | History 1916 | Harvard Law School 2694

Semester: , offered: .

This course, offered at the Harvard Law School and jointly in the college (open to advanced undergraduates), will examine and compare the rules and standards of evidence in law, history, science, and journalism. What counts as proof in these fields varies and has changed over time, often wildly. Emphasis will be on the histories of Western Europe and the United States, from the middle ages to the present, with an eye toward understanding how ideas about evidence shape criminal law and with special attention to the rise of empiricism in the nineteenth century, the questioning of truth in the twentieth, and the consequences of the digital revolution in the twenty-first. Topics will include the histories of trial by ordeal, trial by jury, spectral evidence, the footnote, case law, fact checking, expert testimony, the polygraph, statistics, DNA, anonymous sources, and big data.

Related Materials

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Jill Lepore, David Blight, Drew Gilpin Faust John Fabian Witt . 2024. Brief of American Historians as Amici Curiae Supporting Respondents (Jan. 29, 2024) (No. 23-719) . Amicus Brief

Few, if any, historians have brought such insight, wisdom, and empathy to public discourse as Jill Lepore. Arriving at The New Yorker in 2005, Lepore, with her panoptical range and razor-sharp style, brought a transporting freshness and a literary vivacity to everything from profiles of long-dead writers to urgent constitutional analysis to an unsparing scrutiny of the woeful affairs of the nation itself. The astonishing essays collected in The Deadline offer a prismatic portrait of Americans’ techno-utopianism, frantic fractiousness, and unprecedented—but armed—aimlessness. From lockdowns and race commissions to Bratz dolls and bicycles, to the losses that haunt Lepore’s life, these essays again and again cross what she calls the deadline , the “river of time that divides the quick from the dead.” Echoing Gore Vidal’s United States in its massive intellectual erudition, The Deadline , with its remarkable juxtaposition of the political and the personal, challenges the very nature of the essay—and of history—itself.

In the most ambitious, one-volume American history in decades, award-winning historian Jill Lepore offers a magisterial account of the origins and rise of a divided nation.

The American experiment rests on three ideas—“these truths,” Jefferson called them—political equality, natural rights, and the sovereignty of the people. And it rests, too, on a fearless dedication to inquiry, writes Jill Lepore in a groundbreaking investigation into the American past that places truth itself at the center of the nation’s history. In riveting prose, These Truths tells the story of America, beginning in 1492, to ask whether the course of events has proven the nation’s founding truths, or belied them. “A nation born in contradiction, liberty in a land of slavery, will fight forever over the meaning of its history,” Lepore writes, finding meaning in those very contradictions as she weaves American history into a majestic tapestry of faith and hope, of peril and prosperity, of technological progress and moral anguish. Part spellbinding chronicle, part old-fashioned civics book, These Truths, filled with arresting sketches of Americans from John Winthrop and Frederick Douglass to Pauli Murray and Phyllis Schlafly, offers an authoritative new history of a great, and greatly troubled, nation.

Praise for These Truths

“[B]rilliant…insightful…It isn’t until you start reading it that you realize how much we need a book like this one at this particular moment.”

—Andrew Sullivan,  The New York Times Book Review

“This sweeping, sobering account of the American past is a story not of relentless progress but of conflict and contradiction, with crosscurrents of reason and faith, black and white, immigrant and native, industry and agriculture rippling through a narrative that is far from completion.”

— The   New York Times Book Review , Editors’ Choice

“[Lepore’s] one-volume history is elegant, readable, sobering; it extends a steadying hand when a breakneck news cycle lurches from one event to another, confounding minds and churning stomachs.”

—Jennifer Szalai,  The New York Times

“Jill Lepore is an extraordinarily gifted writer, and  These Truths  is nothing short of a masterpiece of American history. By engaging with our country's painful past (and present) in an intellectually honest way, she has created a book that truly does encapsulate the American story in all its pain and all its triumph.”

–Michael Schaub,  NPR  

“A splendid rendering—filled with triumph, tragedy, and hope—that will please Lepore’s readers immensely and win her many new ones.”

— Kirkus Reviews , starred review

“This thought-provoking and fascinating book stands to become the definitive one-volume U.S. history for a new generation.”

— Library Journal , starred review

“An ambitious and provocative attempt to interpret American history as an effort to fulfill and maintain certain fundamental principles. . . . Lepore is a historian with wide popular appeal, and this comprehensive work will answer readers’ questions about who we are as a nation.”

— Booklist , starred review

“Astounding… [Lepore] has assembled evidence of an America that was better than some thought, worse than almost anyone imagined, and weirder than most serious history books ever convey. Armed with the facts of what happened before, we are better able to approach our collective task of figuring out what should happen now . . . Perhaps instead of the next U2 album, Apple could make a copy of  These Truths  appear on every iPhone—not only because it offers the basic civics education that every American needs, but because it is a welcome corrective to the corrosive histories peddled by partisans.”

—Casey N. Cep,  Harvard Magazine

“In her epic new work, Jill Lepore helps us learn from whence we came.”

— Oprah Magazine

“Sweeping and propulsive.”

“ ‘An old-fashioned civics book,’ Harvard historian and  New Yorker  contributor Jill Lepore calls it, a glint in her eye. This fat, ludicrously ambitious one-volume history is a lot more than that. In its spirit of inquiry, in its eager iconoclasms,  These Truths  enacts the founding ideals of the country it describes.

― Huffington Post

“It's an audacious undertaking to write a readable history of America, and Jill Lepore is more than up to the task. But  These Truths  is also an astute exploration of the ways in which the country is living up to its potential, and where it is not.”

— Business Insider

“Gutsy, lyrical, and expressive… [ These Truths ] is a perceptive and necessary contribution to understanding the American condition of late.… It captures the fullness of the past, where hope rises out of despair, renewal out of destruction, and forward momentum out of setbacks.”

—Jack E. Davis,  Chicago Tribune

“Lepore’s brilliant book,  These Truths , rings as clear as a church bell, the lucid, welcome yield of clear thinking and a capable, curious mind.”

—Karen R. Long,  Newsday

“ A splendid rendering —filled with triumph, tragedy, and hope—that will please Lepore’s readers immensely and win her many new ones.”

“An ambitious and provocative attempt to interpret American history as an effort to fulfull and maintain certain fundamental principles . . . Lepore is a historian with wide popular appeal, and this comprehensive work will answer readers’ questions about who we are as a nation.”

“In this time of disillusionment with American politics, Jill Lepore’s beautifully written book should be essential reading for everyone who cares about the country’s future. Her history of the United States reminds us of the dilemmas that have plagued the country and the institutional strengths that have allowed us to survive as a republic for over two centuries. At a minimum, her book should be required reading for every federal officeholder.”

—Robert Dallek, author of Franklin D. Roosevelt

"No one has written with more passion and brilliance about how a flawed and combustible America kept itself tethered to the transcendent ideals on which it was founded. If the country is to recover from its current crisis, These Truths will illuminate the way."

—Gary Gerstle, author of Liberty and Coercion

“Who can write a comprehensive yet lucid history of the sprawling United States in a single volume? Only Jill Lepore has the verve, wit, range, and insights to pull off this daring and provocative book. Interweaving many lively biographies, These Truths illuminates the origins of the passions and causes, which still inspire and divide Americans in an age that needs all the truth we can find.”

—Alan Taylor, author of American Revolutions

“Lepore brings a scholar's comprehensive rigor and a poet's lyrical precision to this singular single-volume history of the United States. Understanding America's past, as she demonstrates, has always been a central American project. She knows that the "story of America" is as plural and mutable as the nation itself, and the result is a work of prismatic richness, one that rewards not just reading but rereading. This will be an instant classic.”

—Kwame Anthony Appiah, author of The Lies that Bind

“Anyone interested in the future of the Republic must read this book. One of our greatest historians succeeds, where so many have failed, to make sense of the whole canvas of our history. Without ignoring the horrors of conquest, slavery or recurring prejudices, she manages nonetheless to capture the epic quality of the American past. With passion, compassion, wit, and remarkable insight, Lepore brings it all to life, the good, the bad, the beautiful and the ugly. This is a manifesto for our necessarily shared future.”

—Lynn Hunt, author of History: Why it Matters

“In this inspiring and enlightening book, Jill Lepore accomplishes the grand task of telling us what we need to know about our past in order to be good citizens today. Avoiding political and ideological agendas, she confronts the contradictions that come from being born a land of both liberty and slavery, but she uses such conflicts to find meaning—and hope—in the tale of America’s progress.”

—Walter Isaacson, University Professor of History, Tulane, author of The Innovators

"Lepore is a truly gifted writer with profound insight."

"This vivid history brings alive the contradictions and hypocrisies of the land of the free"

- David Aaronovitch, The Times

"A history for the 21st century, far more inclusive than the standard histories of the past"

"Monumental ... a crucial work for presenting a fresh and clear-sighted narrative of the entire story ... exciting and page-turningly fascinating, in one of those rare history books that can be read with pleasure for its sheer narrative energy"

- Simon Winchester, New Statesman

"Jill Lepore is that rare combination in modern life of intellect, originality and style"

- Amanda Foreman, TLS

A brilliant, revelatory account of the Cold War origins of the data-mad, algorithmic twenty-first century, from the author of the acclaimed international bestseller,  These Truths .

The Simulmatics Corporation, founded in 1959, mined data, targeted voters, accelerated news, manipulated consumers, destabilized politics, and disordered knowledge--decades before Facebook, Google, Amazon, and Cambridge Analytica. Silicon Valley likes to imagine it has no past but the scientists of Simulmatics are the long-dead grandfathers of Mark Zuckerberg and Elon Musk. Borrowing from psychological warfare, they used computers to predict and direct human behavior, deploying their “People Machine” from New York, Cambridge, and Saigon for clients that included John Kennedy’s presidential campaign, the  New York Times , Young & Rubicam, and, during the Vietnam War, the Department of Defense. Jill Lepore, distinguished Harvard historian and  New Yorker  staff writer, unearthed from the archives the almost unbelievable story of this long-vanished corporation, and of the women hidden behind it. In the 1950s and 1960s, Lepore argues, Simulmatics invented the future by building the machine in which the world now finds itself trapped and tormented, algorithm by algorithm.

“A person can't help but feel inspired by the riveting intelligence and joyful curiosity of Jill Lepore.  Knowing that there is a mind like hers in the world is a hope-inducing thing.”

            --George Saunders

“Everything Lepore writes is distinguished by intelligence, eloquence, and fresh insight.  If Then  is that, and even more: It’s absolutely fascinating, excavating a piece of little-known American corporate history that reveals a huge amount about the way we live today and the companies that define the modern era.”

            --Susan Orlean

“Data science, Jill Lepore reminds us in this brilliant book, has a past, and she tells it through the engrossing story of Simulmatics, the tiny, long-forgotten company that helped invent our data-obsessed world, in which prediction is seemingly the only knowledge that matters. A captivating, deeply incisive work.”

            —Frederik  Logevall , Pulitzer Prize-winning author of  Embers of War: The Fall of an Empire and the Making of America’s Vietnam

“Think today’s tech giants invented data mining and market manipulation? Think again. In this page-turning, eye-opening history, Jill Lepore reveals the Cold War roots of the tech-saturated present, in a thrilling tale that moves from the campaigns of Eisenhower and Kennedy to ivied think tanks, Madison Avenue ad firms, and the hamlets of Vietnam. Told with verve, grace, and humanity,  If Then  is an essential, sobering story for understanding our times.”

—Margaret O’Mara, author of  The Code: Silicon Valley and the Remaking of America

“It didn’t all start with Facebook. We have long been fascinated with the potential of using computing technology to predict human behavior. In another fast-paced narrative, Jill Lepore brilliantly uncovers the history of the Simulmatics Corp, which launched the volatile mix of computing, politics and personal behavior that now divides our nation, feeds on private information, and weakens the strength our democratic institutions. If you want to know where this all started, you need not look any further--read this book!”

— Julian Zelizer, author of  Burning Down the House: Newt Gingrich, the Fall of a Speaker and the Rise of the New Republican Party 

Jill Lepore is the David Woods Kemper ’41 Professor of American History at Harvard University and is also a staff writer at  The New Yorker . A two-time Pulitzer Prize finalist, her many books include the international bestseller,  These Truths .

A New York Times and National Bestseller and Winner of the 2015 American History Book Prize

"Ms. Lepore’s lively, surprising and occasionally salacious history is far more than the story of a comic strip. The author, a professor of history at Harvard, places Wonder Woman squarely in the story of women’s rights in America—a cycle of rights won, lost and endlessly fought for again. Like many illuminating histories, this one shows how issues we debate today were under contention just as vigorously decades ago, including birth control, sex education, the ways in which women can combine work and family, and the effects of 'violent entertainment' on children. 'The tragedy of feminism in the twentieth century is the way its history seemed to be forever disappearing,' Ms. Lepore writes. Her superb narrative brings that history vividly into the present, weaving individual lives into the sweeping changes of the century.” —The Wall Street Journal

“Lepore’s brilliance lies in knowing what to do with the material she has. In her hands, the Wonder Woman story unpacks not only a new cultural history of feminism, but a theory of history as well.” — New York Times Book Review   “Lepore specializes in excavating old flashpoints—forgotten or badly misremembered collisions between politics and cultural debates in America’s past. She lays out for our modern sensibility how some event or social problem was fought over by interest groups, reformers, opportunists, and “thought leaders” of the day. The result can look both familiar and disturbing, like our era’s arguments flipped in a funhouse mirror….Besides archives and comics Lepore relies on journalism, notebooks, letters, and traces of memoir left by the principals, as well as interviews with surviving colleagues, children, and extended family. Her discipline is worthy of a first-class detective….Lepore convinces us that we should know more about early feminists whose work Wonder Woman drew on and carried forward….A key spotter of connections, Lepore retrieves a remarkably recognizable feminist through-line, showing us 1920s debates about work-life balance, for example, that sound like something from The Atlantic in the past decade.” —New York Review of Books   “Even non-comix nerds (or those too young to remember Lynda Carter) will marvel at Jill Lepore’s deep dive into the real-world origins of the Amazonian superhero with the golden lasso. The fact that a polyamory enthusiast created her partly as a tribute to the reproductive-rights pioneer Margaret Sanger is, somehow, only the fourth or fifth most interesting thing in Ms. Woman’s bizarre background.” —New York Magazine   “With a defiantly unhurried ease, Lepore reconstructs the prevailing cultural mood that birthed the idea of Wonder Woman, carefully delineating the conceptual debt the character owes to early-20th-century feminism in general and the birth control movement in particular….Again and again, she distills the figures she writes about into clean, simple, muscular prose, making unequivocal assertions that carry a faint electric charge…[and] attain a transgressive, downright badass swagger.” —Slate   “Deftly combines biography and cultural history to trace the entwined stories of Marston, Wonder Woman, and 20th-century feminism….Lepore – a professor of American history at Harvard, a New Yorker writer, and the author of “Book of Ages” – is an endlessly energetic and knowledgeable guide to the fascinating backstory of Wonder Woman. She’s particularly skillful at showing the subtle process by which personal details migrate from life into art.” —Christian Science Monitor   “Wonder Woman, everyone's favorite female superhero (bulletproof bracelets, hello!), gets the Lasso of Truth treatment in this illuminating biography. Lepore, a Harvard prof and New Yorker writer, delves into the complicated family life of Wonder Woman's creator (who invented the lie detector, BTW), examines the use of bondage in his comics, and highlights the many ways in which the beloved Amazonian princess has come to embody feminism.” —Cosmopolitan   “The Secret History of Wonder Woman relates a tale so improbable, so juicy, it’ll have you saying, “Merciful Minerva!”… an astonishingly thorough investigation of the man behind the world’s most popular female superhero…. Lepore has assembled a vast trove of images and deploys them cunningly. Besides a hefty full-color section of Wonder Woman art in the middle, there are dozens of black-and-white pictures scattered throughout the text. Many of these are panels from Marston’s comics that mirror events in his own life. Combined with Lepore’s zippy prose, it all makes for a supremely engaging reading experience.” —Etelka Lehoczky, NPR   “If it makes your head spin to imagine a skimpily clad pop culture icon as (spoiler alert!) a close relation of feminist birth control advocate Margaret Sanger, then prepare to be dazzled by the truths revealed in historian Jill Lepore’s “The Secret History of Wonder Woman.” The story behind Wonder Woman is sensational, spellbinding and utterly improbable. Her origins lie in the feminism of the early 1900s, and the intertwined dramas that surrounded her creation are the stuff of pulp fiction and tabloid scandal….It took a super-sleuth to uncover the mysteries of this intricate history, hidden from view for more than half a century. With acrobatic research prowess, muscular narrative chops and disarming flashes of humor, Lepore rises to the challenge, bringing to light previously unknown details and deliberately obfuscated connections.” —San Francisco Chronicle   “This captivating, sometimes racy, charming illustrated history is one part biography of the character and one part biography of her fascinating creator, psychologist and inventor William Moulton Marston—an early feminist who believed, way before his time, that the world would be a better place if only women were running it….In the process of bringing her ‘superhero’ to life in this very carefully researched, witty secret ‘herstory,’ Lepore herself emerges as a kind of superheroine: a woman on a mission—as energetic, powerful, brilliant and provocative as her subject.” —Good Housekeeping   “This book is important, readable scholarship, making the connection between popular culture and the deeper history of the American woman’s fight for equality….Lepore restores Wonder Woman to her rightful and righteous place.” —The Kansas City Star “Fascinating…often brilliant….Through assiduous research (the endnotes comprise almost a third of the book and are often very interesting reading), Lepore unravels a hidden history, and in so doing links her subjects’ lives to some of the most important social movements of the era. It’s a remarkable, thought-provoking achievement.” —Bookpage   “The Marston family’s story is ripe for psychoanalysis. And so is The Secret History , since it raises interesting questions about what motivates writers to choose the subjects of their books. Having devoted her last work to Jane Franklin Mecom, Benjamin Franklin’s sister, Lepore clearly has a passion for intelligent, opinionated women whose legacies have been overshadowed by the men they love. In her own small way, she’s helping women get the justice they deserve, not unlike her tiara’d counterpart….It has nearly everything you might want in a page-turner: tales of S&M, skeletons in the closet, a believe-it-or-not weirdness in its biographical details, and something else that secretly powers even the most “serious” feminist history—fun.” —Entertainment Weekly   “An origin story far deeper, weirder, and kinkier than anything a cartoonist ever invented.” —Vulture   “Lepore restores Wonder Woman to her rightful place as an essential women’s rights icon in this dynamically researched and interpreted, spectacularly illustrated, downright astounding work of discovery that injects new zest into the history of feminism.” —Booklist (*starred review*)

“The fullest and most fascinating portrait ever created about the complicated, unconventional family that inspired one of the most enduring feminist icons in pop culture…. The Secret History of Wonder Woman is its own magic lasso, one that compels history to finally tell the truth about Wonder Woman—and compels the rest of us to behold it.” — Los Angeles Times

“ The Secret History of Wonder Woman  is as racy, as improbable, as awesomely righteous, and as filled with curious devices as an episode of the comic book itself. In the nexus of feminism and popular culture, Jill Lepore has found a revelatory chapter of American history. I will never look at Wonder Woman’s bracelets the same way again.” —Alison Bechdel, author of Fun Home  

"Hugely entertaining." -- The Atlantic

“ Lepore has an astonishing story and tells it extremely well. She acts as a sort of lie detector, but proceeds through elegant narrative rather than binary test. Sentences are poised, adverbs rare. Each chapter is carefully shaped. At a time when few are disposed to see history as a branch of literature, Lepore occupies a prominent place in American letters. Her microhistories weave compelling lives into larger stories.” —The Daily Beast   “In the spirited, thoroughly reported "The Secret History of Wonder Woman," Jill Lepore recounts the fascinating details behind the Amazonian princess' origin story….[Lepore]seamlessly shifts from the micro to the macro….A panel depicting this labor unrest is just one of scores that appear throughout Lepore's book, further amplifying the author's vivid prose.” —Newsday   “A Harvard professor with impeccable scholarly credentials, Lepore treats her subject seriously, as if she is writing the biography of a feminist pioneer like Margaret Sanger, the founder of the birth control movement — which this book is, to an extent….Through extensive research and a careful reading of the Wonder Woman comic books, she argues convincingly that the story of this character is an indelible chapter in the history of women’s rights.” —Miami Herald  

A Finalist for the 2013 National Book Award for Nonfiction

From one of our most accomplished and widely admired historians, a revelatory portrait of Benjamin Franklin’s youngest sister and a history of history itself. Like her brother, Jane Franklin was a passionate reader, a gifted writer, and an astonishingly shrewd political commentator. Unlike him, she was a mother of twelve. Benjamin Franklin, who wrote more letters to his sister than he wrote to anyone else, was the original American self-made man; his sister spent her life caring for her children. They left very different traces behind. Making use of an amazing cache of little- studied material, including documents, objects, and portraits only just discovered, Jill Lepore brings Jane Franklin to life in a way that illuminates not only this one woman but an entire world—a world usually lost to history. Lepore’s life of Jane Franklin, with its strikingly original vantage on her remarkable brother, is at once a wholly different account of the founding of the United States and one of the great untold stories of American history and letters: a life unknown.

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Middle East crisis — explained

The conflict between Israel and Palestinians — and other groups in the Middle East — goes back decades. These stories provide context for current developments and the history that led up to them.

U.S. report says it's 'reasonable to assess' that Israel has violated humanitarian law

Jeongyoon Han

Smoke rises over southern Gaza Strip after an Israeli airstrike on May 7. Amir Levy/Getty Images hide caption

Smoke rises over southern Gaza Strip after an Israeli airstrike on May 7.

A U.S. State Department report said Friday it was "reasonable to assess" that Israel has violated international humanitarian law while carrying out military operations in Gaza. But the report stopped short of drawing any final or sweeping conclusions about Israeli conduct in the war against Hamas.

The Biden administration voluntarily undertook this review of Israel and six other countries receiving U.S. weapons. While the administration is facing criticism at home and abroad, this report does not require it to take any specific actions.

The report reflects an administration that's become increasingly critical of Israel and frustrated with the way it's handling the war, though President Biden insists he still supports Israel and its aim of defeating Hamas in Gaza.

The report looked at two key questions: whether Israel has violated international law while using U.S. weapons, and whether Israel is restricting humanitarian aid.

On the first question, the report said: "It is reasonable to assess that [U.S.] defense articles ... have been used by Israeli security forces since October 7 in instances inconsistent with its [International Humanitarian Law] obligations or with established best practices for mitigating civilian harm."

The State Department findings cited multiple examples where large numbers of Palestinian civilians were killed in Israeli airstrikes. The reports said these instances raised serious concerns, but the U.S. did not have enough evidence to reach definitive conclusions.

More than 34,000 Palestinians have been killed in Gaza, according to Palestinian health officials, adding that about two-thirds were women and children. Israel, meanwhile, has said it has killed more than 13,000 Hamas fighters in Gaza.

On the question of humanitarian aid for Gaza, the report stated that Israel initially did not cooperate with the U.S. and international aid groups to let in humanitarian aid and thus "contributed significantly" to the lack of aid to the Palestinian people.

But that has changed over time, the report added.

"We do not currently assess that the Israeli government is prohibiting or otherwise restricting the transport or delivery of U.S. humanitarian assistance," it said.

However, aid groups say that incoming assistance has all but halted this week after Israeli troops took over the Rafah border crossing along Gaza's southern frontier with Egypt.

The Biden administration announced this week that the U.S. was withholding a weapons shipment to Israel consisting of more than 3,000 large bombs. And in an interview this week, Biden suggested he could pause the delivery of additional weapons as well.

The U.S. has been sending large quantities of weapons to Israel for decades, and ramped up deliveries after the Hamas attack on Oct. 7 that ignited the war.

The withholding of a single shipment of weapons is unlikely to have any impact on Israeli operations in Gaza, though it signals the administration's sense that Israel should take a different approach.

Red lines and Rafah

Biden and other top U.S. officials say they support Israel's goal of defeating Hamas in Rafah, its last stronghold, where it is believed to have several thousand fighters.

But the U.S. does not want to see a full-fledged assault on the city, similar to elsewhere in Gaza, which led to so many civilian casualties.

The U.S. says it has been demanding, but has not seen, a credible Israeli plan to move civilians out of harm's way in Rafah. The city had around 200,000 residents before the war began, but now has more than 1 million, many living in tent camps.

The Biden administration issued a national security memorandum in February which mandated the report on Israel and six other countries receiving weapons from the U.S., after congressional Democrats pushed Biden to determine whether Israel is violating domestic and international law in its war with Hamas.

The report and the memorandum from February does not have the legal teeth that would require the U.S. to stop arms transfers even if a country violates international law or has a more likely than not chance of doing so.

Biden and the Congress have the option to take further action. But Sarah Harrison, a senior analyst specializing in U.S. foreign policy at the International Crisis Group, said she doesn't expect that to happen.

The report, she said, "could make it harder for him to defend the unconditional assistance approach," Harrison said. But she emphasized the report does not require a change in his policy. "It's up to the president. It's still discretionary."

Meanwhile, Israeli leader Benjamin Netanyahu has maintained repeatedly that he will not bow to pressure from anywhere, including the White House.

The report presents further questions as to how Biden will navigate his tense relationship with Netanyahu. But Harrison said little has actually changed in Biden's policy, particularly on Rafah.

"He's threatening to change it, but not actually changing it," she said. "There are operations ongoing in Rafah, so it's not even clear what his red line is."

To revisit this article, visit My Profile, then View saved stories .

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Joel Khalili

Craig Wright Lied About Creating Bitcoin and Faked Evidence, Judge Rules

A judge in the UK High Court has ruled that computer scientist Craig Wright lied “extensively and repeatedly” and committed forgery “on a grand scale” in aid of a years-long quest to prove he is Satoshi Nakamoto, the creator of Bitcoin.

In a written judgment published on May 20, Justice James Mellor ruled that Wright forged reams of documents in service of his charade. “It is clear that Dr. Wright engaged in the deliberate production of false documents to support false claims and use the Courts as a vehicle for fraud,” he wrote. “I am entirely satisfied that Dr. Wright lied to the Court extensively and repeatedly. All his lies and forged documents were in support of his biggest lie: his claim to be Satoshi Nakamoto.”

“Dr. Wright presents himself as an extremely clever person,” Mellor added. “However, in my judgment, he is not nearly as clever as he thinks he is.”

The judgment—the culmination of a six-week trial held earlier in the year—marks the end of a civil lawsuit launched by the Crypto Open Patent Alliance (COPA), a nonprofit consortium of crypto companies, against Wright. The organization asked the court to declare that Wright is not the creator of Bitcoin, to prevent him from carrying forward multiple separate lawsuits against Bitcoin developers and other parties founded on the claim.

Wright did not immediately respond to a request for comment. In a statement posted to X, Wright said he intends to appeal the ruling.

In a winding cross-examination , Wright was presented with documents bearing hundreds of alleged indications of forgery. Wright justified the abnormalities with a fluency that implied extensive preparation, but failed to win over the judge. On March 14, the final day of the trial, Mellor delivered a rare snap verdict : “The evidence is overwhelming,” he told the courtroom. “Dr. Wright is not the person who adopted or operated under the pseudonym Satoshi Nakamoto.”

The swift ruling demonstrated “how utterly unfounded each of [Wright’s] claims were proven to be,” says Paul Grewal, chief legal officer at crypto exchange Coinbase, a member of COPA. “Dr. Wright’s claims were shown not only to be false but utterly fanciful.”

In the weeks since the initial ruling, Wright has abandoned multiple lawsuits that were either connected to or built upon his claim to being the creator of Bitcoin.

On April 11, Wright dropped an appeal of a lawsuit in Norway against crypto influencer Magnus Granath—known by the pseudonym Hodlonaut—who in 2019 described Wright as a “pathetic scammer” in a post on X. (A parallel claim has been dropped in the UK.) A few days later, Wright killed another lawsuit in which his company, Tulip Trading, accused Bitcoin developers of violating their fiduciary duties by refusing to help the firm recover a large amount of bitcoin allegedly lost in a hack.

Three further lawsuits—in which Wright accuses Bitcoin developers, as well as crypto exchanges Coinbase and Kraken, of violating his intellectual property rights over Bitcoin—will be bound by the COPA ruling. These cases remain in place, at least temporarily, pending a possible appeal by Wright.

Reece Rogers

Brian Barrett

Nilesh Christopher

“We’ve seen a cascading effect from the pronouncement on a host of other litigations globally,” says Grewal. “For people outside of crypto, [all this] might sound cartoonish. But with Wright’s claims falling by the wayside, the community can exhale. We think it’s a real win.”

The ruling has also had implications for Bitcoin Satoshi Vision, or BSV, a separate cryptocurrency network created by Wright in 2018. The idea for BSV is to cleave “as closely as possible to Satoshi’s original design,” as the website describes it . In the days after the judge ruled that Wright is not Satoshi, the price of the BSV token fell by 40 percent .

The BSV Association did not respond immediately to a request for comment.

In declaring that Wright is not Satoshi, the judgment will prevent him from bringing further lawsuits in the UK. It was crafted, Mellor writes, to ensure that Wright would not “have any possible basis on which to threaten [developers] with copyrights or database rights stemming from the work done by Satoshi Nakamoto.” The judge will also decide at a later hearing whether to impose any specific injunctions upon Wright.

However, the geographical scope of the judgment is limited, leaving an opening for Wright to continue to pursue his claim to IP rights over Bitcoin in other legal jurisdictions.

The general principles of copyright are “harmonized” under an agreement adopted by the overwhelming majority of countries, says James Marsden, a senior associate at law firm Dentons, which means the COPA ruling is likely to be persuasive to other courts asked to address Wright’s claim to holding IP rights over Bitcoin. However, “copyright is territorial,” he says. “The courts of each country will analyze a copyright case on their own basis.”

In his testimony at trial, Wright also intimated that he could wield his trove of patents relating to blockchain technology to bring further claims against Bitcoin developers. A ruling that Wright is not the creator of Bitcoin would not prevent him doing so. “It’s very hard for any court to craft a judgment that prevents a committed party from repeating bogus claims,” says Grewal.

Granath, the defendant in the Norway libel case brought by Wright, imagines that Wright’s continued pursuit of his claim to being Satoshi will depend on the availability of funding.

The source of Wright’s funding came into question at trial. It is alleged by COPA that online gambling tycoon Calvin Ayre has financed Wright’s various litigations. At trial, Wright denied that Ayre had bankrolled his lawsuits. Ayre did not respond to a request for comment.

In March, Mellor placed a freezing order on $7.6 million of Wright’s assets to prevent him from taking measures to “evade the costs consequences of his loss at trial.” COPA has “a very powerful claim to be awarded a very substantial sum in costs,” the judge wrote.

“I think this is down to funding now, not Wright’s desire to continue to claim he is Satoshi,” says Granath. “I think the UK judgment makes any further lawfare based on Wright’s claims futile, meaning the will and rationality to fund him is not there anymore.”

For its part, COPA is hoping that the completeness of the judge’s findings against Wright—and the resulting damage to his credibility—will discourage him from pursuing further legal action, even if the option remains available to him.

“This was an extraordinary proceeding. It could not have sent a clearer message to Dr. Wright and anyone else paying attention,” says Grewal. “I’m not terribly worried about Dr. Craig Wright.”

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US says Israel’s use of US arms likely violated international law, but evidence is incomplete

U.S. President Joe Biden boards Marine One at Moffett Airfield in Mountain View, Calif., Thursday, May 9, 2024. (Jose Carlos Fajardo/Pool Photo via AP)

Palestinians mourn their relatives killed in the Israeli bombardment of the Gaza Strip, at a hospital in Rafah, Gaza, Friday, May 10, 2024. (AP Photo/Ismael Abu Dayyah)

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WASHINGTON (AP) — The Biden administration said Friday that Israel’s use of U.S.-provided weapons in Gaza likely violated international humanitarian law but that wartime conditions prevented U.S. officials from determining that for certain in specific airstrikes.

The finding of “reasonable” evidence to conclude that the U.S. ally had breached international law protecting civilians in the way it conducted its war against Hamas was the strongest statement that the Biden administration has yet made on the matter. It was released in a summary of a report being delivered to Congress on Friday.

But the caveat that the administration wasn’t able to link specific U.S. weapons to individual attacks by Israeli forces in Gaza could give the administration leeway in any future decision on whether to restrict provisions of offensive weapons to Israel.

The first-of-its-kind assessment, which was compelled by President Joe Biden’s fellow Democrats in Congress, comes after seven months of airstrikes, ground fighting and aid restrictions that have claimed the lives of nearly 35,000 Palestinians, mostly women and children.

While U.S. officials were unable to gather all the information they needed on specific strikes, the report said that given Israel’s “significant reliance” on U.S.-made weapons, it was “reasonable to assess” that they had been used by Israel’s security forces in instances “inconsistent” with its obligations under international humanitarian law “or with best practices for mitigating civilian harm.”

Israel’s military has the experience, technology and know-how to minimize harm to civilians, but “the results on the ground, including high levels of civilian casualties, raise substantial questions as to whether the IDF is using them effectively in all cases,” the report said.

International human rights groups and a review by an unofficial panel of former State and military officials, academic experts and others had pointed to more than a dozen Israeli airstrikes for which they said there were credible evidence of violations of the laws of war and humanitarian law. Targets included aid convoys, medical workers, hospitals, journalists, schools and refugee centers and other sites that have broad protection under international law.

They argued that the civilian death toll in many strikes in Gaza — such as an Oct. 31 strike on an apartment building reported to have killed 106 civilians — was disproportionate to the value of any military target.

Israel says it is following all U.S. and international law, that it investigates allegations of abuse by its security forces and that its campaign in Gaza is proportional to the existential threat it says is posed by Hamas.

Rep. Michael McCaul, the Republican chairman of the House Foreign Affairs Committee, said the review “only contributes to politically motivated anti-Israel sentiment” and should never have been done.

“Now is the time to stand with our ally Israel and ensure they have the tools they need,” he said in a statement.

But Sen. Chris Van Hollen, the Maryland Democrat who led the push in Congress, told reporters that even even though the administration had reached a general finding, “they’re ducking a determination on the hard cases. Politically inconvenient cases.”

The U.S. “treats the government of Israel as above the law,” Amanda Klasing of the Amnesty International USA rights group said in a statement.

Biden has tried to walk an ever-finer line in his support of Prime Minister Benjamin Netanyahu’s war against Hamas. The U.S. leader is a target of growing rancor at home and abroad over the soaring Palestinian death toll and the onset of famine, caused in large part by Israeli restrictions on the movement of food and aid into Gaza. Tensions have been heightened further in recent weeks by Netanyahu’s pledge to expand the Israeli military’s offensive in the crowded southern city of Rafah, despite Biden’s adamant opposition.

Ophir Falk, foreign policy adviser to Netanyahu, told The Associated Press that Israel acts in compliance with the laws of armed conflict and the army takes extensive measures to avert civilian casualties, including alerting people to military operations via phone calls and text messages.

Biden, in the closing months of a tough reelection campaign against Donald Trump, faces demands from many Democrats that he cut the flow of offensive weapons to Israel and denunciation from Republicans who accuse him of wavering on support for Israel at its time of need.

The Democratic administration took one of the first steps toward conditioning military aid to Israel in recent days when it paused a shipment of 3,500 bombs out of concern over Israel’s threatened offensive on Rafah , a southern city crowded with more than a million Palestinians, a senior administration official said.

The presidential directive that led to the review, agreed to in February, obligated the Defense and State departments to conduct “an assessment of any credible reports or allegations that such defense articles and, as appropriate, defense services, have been used in a manner not consistent with international law, including international humanitarian law.”

Nothing in the presidential directive would have triggered any cutoff of arms if the administration had more definitively ruled that Israel’s conduct had violated international law.

The agreement also obligated the State and Defense departments to tell Congress whether they deemed that Israel has acted to “arbitrarily to deny, restrict, or otherwise impede, directly or indirectly,” delivery of any U.S.-supported humanitarian aid into Gaza for starving civilians there.

On this question, the report cited “deep concerns” that Israel played a significant role in preventing adequate aid from reaching starving Palestinians. However, it said Israel had recently taken some positive steps, although still inadequate, and the U.S. government did not currently find Israel restricting aid deliveries in a way that violated U.S. law governing foreign militaries that receive U.S. military aid.

Van Hollen accused the administration of glossing over what he said were clear Israeli blocks on food and aid deliveries during much of the war. “That’s why we have hundreds of thousands of Palestinians that have nothing to do with Hamas on the verge of starvation,” he said.

Lawmakers and others who advocated for the review said Biden and previous American leaders have followed a double standard when enforcing U.S. laws governing how foreign militaries use U.S. support, an accusation the Biden administration denies.

Their opponents argued that a U.S. finding against Israel would weaken it at a time it is battling Hamas and other Iran-backed groups. It’s not clear how much Friday’s more in-between verdict would add to pressure on Biden to curb the flow of weapons and money to Israel’s military or further heighten tensions with Netanyahu’s hard-right government.

At the time the White House agreed to the review, it was working to head off moves from Democratic lawmakers and independent Sen. Bernie Sanders of Vermont to start restricting shipments of weapons to Israel.

Israel launched its offensive after an Oct. 7 assault into Israel, led by Hamas, killed about 1,200 people. Two-thirds of the Palestinians killed since then have been women and children, according to local health officials. U.S. and U.N. officials say Israeli restrictions on food shipments since Oct. 7 have brought on full-fledged famine in northern Gaza.

Human rights groups long have accused Israeli security forces of committing abuses against Palestinians and have accused Israeli leaders of failing to hold those responsible to account. In January, in a case brought by South Africa, the top U.N. court ordered Israel to do all it could to prevent death, destruction and any acts of genocide in Gaza, but the panel stopped short of ordering an end to the military offensive.

Biden in December said “indiscriminate bombing” was costing Israel international backing. After Israeli forces targeted and killed seven aid workers from the World Central Kitchen in April, the Biden administration for the first time signaled it might cut military aid to Israel if it didn’t change its handling of the war and humanitarian aid.

Presidents Ronald Reagan and George H.W. Bush, in the 1980s and early 1990s, were the last presidents to openly hold back weapons or military financing to try to push Israel to change its actions in the region or toward Palestinians.

AP White House Correspondent Zeke Miller and Associated Press writer Mike Balsamo contributed to this report.