Although we often speak of ‘the judges’ as though they were a homogeneous group within the court and judicial structure, there is in fact a whole variety of judges, operating in different courts and at different levels in the court hierarchy (quite apart from those legally qualified persons who chair tribunals). At the top of the hierarchy of courts of law are members of the House of Lords and the Court of Appeal, appointed from the ranks of Court of Appeal judges and High Court judges respectively; lower down, the judges of the High Court are appointed from among senior and eminent barristers; and at county court level, Circuit Judges and Recorders are appointed from the ranks of the legal profession – at present still mainly from barristers, though in June 2006, around 10% of Recorders were solicitors.

The exception to this general pattern of judicial recruitment from amongst practising barristers is, of course, found in the magistrates' courts, where the bench only exceptionally comprises trained lawyers; usually, laymen and women are appointed as Justices of the Peace on the basis of their experience and general standing in the local community. Although they receive some training in the law, magistrates are to a large extent dependent for legal knowledge upon their clerks, who are legally qualified and whose task it is to advise the court on matters of law in cases heard before them.

In this chapter we examine the relationships between law, society and morality. A society's ‘code of morality’ may be defined as a set of beliefs, values, principles and standards of behaviour, and such codes are found in all social groups. We noted in chapter 1 how the sociologist Emile Durkheim presented a theory of social cohesion, part of which rested on the notion that in technologically undeveloped societies, such as small tribal groups, there tends to be a single, consensually held moral code (the ‘collective conscience’) to which all members of the group subscribe. In a technologically advanced society such as our own, however, with immense differentiation in terms of social status, income, occupation, ethnic background and so on, it is unlikely that we will find such a monolithic moral code. Rather, as will be argued later in this chapter, there is diversity of moral attitudes on all kinds of social and personal issues.

Most of us, if asked to give an example of an area of moral rules in our society, would probably think of sexual morality, or perhaps acts of violence against the person. It is important to emphasise, however, that morality embraces much more than sex and violence; it is part of dominant ideological currents, whereby dominant beliefs and attitudes conducive to the maintenance of the overall status quo are ‘translated’ into a positive general code involving social attitudes to property, politics and social relationships in general.

We have seen, at various points in this book, the ways in which certain activities and values come to be incorporated into law; such incorporation may be positive, as where the law is used to protect specific interests and values, or negative, as where the law, especially the criminal law, is used to proscribe certain activities because they offend certain dominant values (such as the sanctity of private property or the values attaching to particular moral beliefs), or because they are seen as an affront to the very foundations of social existence (such activities would include murder, rape and other violent behaviour). Definitions of ‘deviant behaviour’, then, are not something ‘pre-social’, that is, eternal, permanent and deriving from periods prior to social life as we know it; rather, they are dependent upon particular social structural arrangements at given periods of history. Whatever the origins of particular legal rules proscribing ‘unacceptable’ behaviour may be, those legal rules do have certain things in common, one of the most important of which is that they invariably provide for some form of legal sanction to be visited upon the offender upon conviction by a court.

Every social group contains within it the elements and conditions in which disputes will arise. Even the smallest social group will experience disputes between its members, and, as we would expect, the larger and more complex a social group becomes, the more varied and, perhaps, frequent will be the disputes which crop up within it. Hardly a day goes by in people's everyday lives without some problem occurring, some argument arising or some resentment or frustration being felt by one person or group over the activities of another. Family rows, arguments with friends, confrontations at work and so on are familiar to most people, as are the various solutions which we use to deal with those disputes.

The simplest disputes are dealt with by various informal, often quite good-natured, means. Within family units, there may be an invocation of an established family custom or rule, or the calling-in of a third party to mediate in the dispute. Rarely would family squabbles result in the initiation of any kind of formal proceedings to settle the matter. Similarly, the social and economic world outside such small units as friends or family rests upon various types of relationships between, for example, business enterprises, employers and employees, traders and consumers, and citizens and government agencies. When considering the frequency with which something goes wrong with the smooth running of these relationships, and a dispute arises, it is important to appreciate that the informal resolution of the problem, through concession or compromise, is by far the most usual way of settling the matter.

To function as gatekeepers, judges must decide whether the scientific expert's testimony is valid scientific knowledge, which Daubert explained as knowledge grounded in scientific method. Although most of us have heard the term “scientific method,” expecting judges to decide whether expert testimony has been derived from its criteria – without more guidance – seems a stretch. As commonly understood, scientific method means taking an idea about how things work, framing it in a testable hypothesis, and testing the hypothesis to see if it holds true, all measured and expressed in mathematical (i.e., probabilistic) terms. However, despite the U.S. Supreme Court's reference to the scientific method as the cornerstone of scientific knowledge, its existence is debatable. First, there is no monolithic scientific method. Karl Popper, the preeminent philosopher of science cited by the Daubert Court, thoroughly debunked any such notion. There is no all-inclusive set of rules that can be applied to science to determine its validity. Differences arise among scientists in different disciplines, and even within the same discipline, with respect to the amount of evidence that is needed to support a theory. Instead, there are many methods and many procedures. The only essential ingredient for good science – and, hence, the only overarching method – is that science must be open to critique and revision.

Purportedly, the scientific method is a way to ensure objectivity; however, the scientific method is no guarantee of objectivity.

Social psychology is suddenly an important argument in law. Increasingly, references to framing effects, hindsight bias, overconfidence, and optimism bias, to name just a few, are pervading the legal literature. Occasionally, such references even creep into court opinions. Jury studies and eyewitness unreliability studies are the subject of admissibility disputes. Behavioral studies are cited as support for everything from antitrust reform and environmental reform to failures in the securities markets. In large measure, this use of social psychology is intended to counter the pervasive influence on legal scholarship (and jurisprudence) of the law and economics movement.

The use of social science for legal argument is by no means a bad thing because it reflects a growing awareness that law can become more effective by using scientific insights into human behavior. However, to properly apply these insights, legal actors (i.e., scholars, judges, and lawyers) need to be intellectually careful to minimize the risk of abuse. With little analysis of the research on which it is based, thousands of legal articles have cited to various aspects of social psychology as though it were accepted dogma, like the laws of thermodynamics. Worse, these legal scholars occasionally attempt to replicate psychological experiments in their own classrooms (and cite such findings as support for their arguments) without any of the benefits of scientific process. Partly because the social psychology research on which they relied was not well integrated with biological knowledge, legal use of social psychology has been woefully unsophisticated.

The rule of law is often described as a search for truth in a system that aspires to rationality. The rule of law is also conceived as a vital safeguard from the paradox of freedom in democracies, in which the strong – physically or economically – if not restrained from preying on the weak, defeat the freedom that enabled them. An integral component of this vision is – at least in the United States and for criminal trials elsewhere in the former Commonwealth countries – the jury. The jury system, which provides a structure for citizen participation and brings the voice of the community into the process of legal decision making, is a key feature of the separation of powers doctrine. At the same time, the bifurcation of decision-making duties between judge and jury has consequences, a primary one being the restriction on the information that the jury will be given and able to use for its determination.

One hotly debated area in this bifurcation has been the use of expert witnesses and the necessity of judicial screening for validity of the expert's science before permitting experts to testify. For scientific evidence, the question now is whether the testimony has met the standards and methods of science. Even in state courts that have eschewed the Daubert standard in favor of the old general acceptance rule, there is increased concern with scientific validity.

In stark contrast to the toxic tort context, judges in criminal cases overwhelmingly permit experts to testify with little or no examination of the scientific basis for their testimony – and this is true in the Commonwealth countries, the United States, and in civil law systems as well. The problem in criminal evidence is that microscopic hair analysis, bitemark identification, voice spectrography, handwriting analysis, and even such time-honored prosecutorial tools of identification as fingerprinting have crept into court with virtually no demonstration of their scientific bases. Each of these identification techniques is based on the theory that fingerprints, voice patterns, bitemarks, and other identifying evidence are uniquely personal. This is a theory based on faith (and – in the case of fingerprints, at least – some experience), not on the rigorous testing expected of scientific disciplines or required to meet the Daubert standards of admissibility.

A number of reasons have been proposed for this lackadaisical gatekeeping, but tradition undoubtedly has a strong influence here. Many of the stalwart techniques of criminal forensics crept into the courtroom nearly a century ago under the guise of science, although most had little rigorous study to support them. Judges undoubtedly fear that if rigorous gatekeeping standards were imposed now, after decades of use – and these techniques were found wanting – there would be drastic consequences for criminal justice.

The struggle over what counts as science is in dire straits when it comes to capital sentencing proceedings, where the judiciary has flung wide the gates to wholly unscientific expert testimony. For a democratic system, where the rule of law is foundational in asserting that the solution to the problems of power and freedom is to make the law apply to everyone and to provide rational criteria for distinguishing legitimate from illegitimate uses of power, this lack of rationality has consequences. Judicial failure to scrutinize expert testimony relating to future dangerousness results in a massive failure of intellectual due process.

As discussed in Chapter 2, evidentiary rules are based on the truth-seeking rationality goal of the rule of law. One consequence of this idea is that the methodologies of the justice system should have truth-generating capacity – a notion of due process. A second consequence is a concern for accurate evidentiary input: in order to reach a justifiable decision, reasoning must be based on trustworthy information. A third consequence of the aspiration to rationality is that even trustworthy facts must have some logical tendency to prove or disprove an issue in the case. This framework for justice is the inspiration for the rules of evidence, and a fundamental tenet is that only facts having relevance – rational probative value – should be admissible in the search for truth.

In one important category of proceedings, however, this framework is tossed to the winds. Sentencing hearings have become an evidentiary free-for-all.

Domestic violence is all too often the hidden fulcrum catapulting litigants into court. Far too often it remains a concealed force. Lawyers may fail to raise domestic violence as an issue, unaware of its impact on their clients' decisions. Judges may refuse to consider domestic violence, finding it irrelevant even when it could explain the reasonableness of a defendant's actions. Courts display an extraordinary reluctance to grapple with its implications. This is especially apparent in the homicide justification of self-defense.

Complicating these issues of admissibility are competing visions of equality under the law. A defining aspect of justice is the requirement of equal treatment under the law. Equality under the law is far from a self-defining concept, however, and much legal debate has focused on its definition, with some arguing for formal equality and others for substantive equality. Evidence law, no less than other legal rules, is subject to the debate about what constitutes equality.

The courts' failure to recognize the impact of domestic violence in making their evidentiary rulings can have drastic effects. Judges frequently misapply evidentiary rules, ignore established precedent, and circumvent criteria for scientific validity. On one hand, circumstances that are normally admissible in male-on-male violence cases become suddenly irrelevant and the context distorted in domestic female-to-male violence cases. On the other hand, the widely adopted solution to the perceived unfairness of the traditional rules when applied to battered women who kill is the admission, by legislative or judicial fiat, of expert battered woman syndrome testimony.

Scientific evidence pervades modern legal decisions, whether the decision is made in the courtroom, during the regulatory process, or through legislation. The question of what counts as scientific knowledge has become a focus of heated courtroom and scholarly debate, not only in the United States but also in other common-law countries such as the United Kingdom, Canada, and Australia. Controversies are rife about what is permissible use of genetic information, if chemical exposure causes disease, and whether future dangerousness of violent or sexual offenders can be predicted, among other important topics. Many time-honored methods of criminal identification, such as hair analysis, voice spectography, and bitemark identification, to name a few, have turned out to have no better foundation than ancient divination rituals. This book examines the process of evaluating scientific evidence in both civil and criminal contexts and explains how decisions by nonscientists that embody scientific knowledge can be improved. This is a timely and important subject for anyone interested in the impact of law and science on society.

Evaluating Scientific Evidence: An Interdisciplinary Framework for Intellectual Due Process emphasizes the unifying themes of probabilistic reasoning, hypothesis testing, and interdisciplinarity, and it is intended to provide the guidance that judges and the lawyers advising them need to make scientifically legitimate admissibility determinations. Moreover, scholars who turn to interdisciplinary arguments are confronted with an urgent need for a framework to evaluate scientific argument.

Evaluating Scientific Evidence is intended to provide this guidance to scholars, judges, lawyers, and students of law.