Ashoka reasons that there are the ripple effects of those disturbing DNA exonerations, which have prompted not only renewed scrutiny of forensic laboratories, renewed concern about how line-ups are conducted and photographs presented to eyewitnesses, moves to videotape interrogations, and so on – all, surely, welcome developments – but also legislation to overcome obstacles to admitting ‘new’ evidence, i.e., the results of new DNA tests on old material. Notwithstanding the law’s traditional emphasis on (in Justice Blackmun’s words) “quick, final, and binding” solutions, some states have mandated post-conviction DNA testing, and others have extended or eliminated the statute of limitations where DNA evidence may be available. Here’s the second and concluding part of the author’s in-depth research article, in the weekly column, of Different Truths.
Justice Blackmun wrote for the majority that courts must look not to an expert’s conclusions, but to his methodology, to determine whether proffered testimony is really “scientific . . . knowledge,” and hence reliable. Citing law professor Michael Green citing philosopher of science Karl Popper, and adding a quotation from Carl Hempel for good measure, the ruling suggested four factors for courts to consider: falsifiability, i.e., whether the proffered evidence can be, and has been, tested; the known or potential error rate; peer review and publication; and (in a nod to Frye) acceptance in the relevant scientific community. Dissenting in part, however, Justice Rehnquist pointed out that the word ‘reliable’ nowhere occurs in the text of Rule 702; anticipated that there would be difficulties over whether and how Daubert should be applied to non-scientific expert testimony; worried aloud that federal judges were being asked to be amateur scientists; and questioned the wisdom of his colleagues’ foray into the philosophy of science.
Popper’s and Hempel’s philosophies of science are not compatible. Worse, neither can supply the hoped – for crisp criterion to discriminate the scientific, and hence reliable, from the unscientific, and hence unreliable. No philosophy of science could do this; no such criterion is possible, for not all scientists, and not only scientists, are good, reliable inquirers. Nor is there a uniquely rational mode of inference or procedure of inquiry used by all scientists and only by scientists–no ‘scientific method’ in the sense the Court assumed. Rather, as Einstein once put it, scientific inquiry is “a refinement of our everyday thinking,” superimposing on the inferences, desiderata, and constraints common to all serious empirical inquiry a vast variety of amplifications and refinements of human cognitive powers: instruments of observation, models, and metaphors, mathematical and statistical techniques, experimental controls, etc., devised by generation upon generation of scientists, constantly evolving, and often local to this or that area of science.
So perhaps it is no wonder that in the two subsequent decisions in which it has spoken on the admissibility of expert testimony, the Supreme Court quietly backed away from the confused philosophy of science built into Daubert. In the Court’s ruling in Joiner(a toxic tort case involving PCB exposure), references to Hopper, Pempel, falsifiability, scientific method, etc., are conspicuous by their absence; and the distinction between methodology and conclusions, crucial to Daubert, is repudiated as not really viable after all. And in response to inconsistent rulings across the circuits over the applicability of Daubert to non-scientific experts, in Kumho (a product liability case involving a tire blowout) the Court ruled that Daubert applies to all expert testimony, not only the scientific. According to the Kumho Court, the key word in Rule 702 is “knowledge,” not “scientific”; what matters is whether proffered testimony is reliable, not whether it is science.
However, the Supreme Court certainly didn’t back away from its commitment to federal judges’ gatekeeping responsibilities. Far from it. In Joiner, the Court affirmed that a judge’s decision to allow or exclude scientific testimony, even though it may determine the outcome of a case, is subject only to review for abuse of discretion, not to any more stringent standard. And in Kumho, stressing that the factors listed in Daubert are “flexible,” the Court ruled that a judge may use any, all, or none of them. So, abandoning the false hope of finding a form of words to discriminate “reliable, scientific” testimony from the rest, the Kumho Court left federal judges with wide-ranging responsibility and considerable discretion in determining whether expert testimony is reliable enough for juries to hear, but with little guidance about how to do this.
In the wry words of Federal Judge Avern Cohn: “You do the best you can.” A sensible layperson might suspect that an expert witness is confused, self-deceived, or dishonest, or that he has failed to take account of readily available relevant information; and should be capable of grasping the importance of double-blinding, independence of variables, etc. But the fact is that serious appraisal of the worth of complex scientific evidence (as Dr. Lydgate pointed out long ago) almost always requires much more than an intelligent layperson’s understanding of science: the specialised knowledge needed to realise that an experimenter failed to control for this subtle potentially interfering factor; that these statistical inferences failed to take account of that subtle dependence of variables; that new work has cast doubt on this widely accepted theory; that this journal is credible, that journal notorious for such-and-such editorial bias.
Seminar on DNA
Since Daubert there have been various efforts to educate judges in science – such as the two-day seminar on DNA for Massachusetts Superior Court judges at the Whitehead Institute for Biomedical Research, after which, the director of the institute told The New York Times, they would “understand what is black and white . . . what to allow in the courtroom.” But while a bit of scientific education for judges is certainly all to the good, a few hours in a science seminar will no more turn judges into scientists competent to make subtle and sophisticated scientific judgments than a few hours in a legal seminar would transform scientists into judges competent to make subtle and sophisticated legal judgments; and may risk giving judges the false impression that they are qualified to appraise specialised and complex scientific evidence.
As judges’ gatekeeping responsibilities have grown, so too has their willingness to call directly on the scientific community for help. Since 1975, under FRE 706, a court has had the power to “appoint witnesses of its own selection.” Used in a number of asbestos cases between 1987 and 1990, the practice came to public attention in the late 1990s, when Judge Sam Pointer, to whom several thousand federal silicone breast implant cases had been consolidated, appointed a National Science Panel to report on whether these implants were implicated in the systemic connective tissue diseases attributed to them. In 1998, the four-member panel reported that the evidence did not warrant claims that the implants caused these diseases. (Six months later, a thirteen-member committee of the Institute of Medicine reached the same conclusion.) The plan had been for the videotaped testimony of panel members to be presented at trial; after the contents of the report became known, however, and before the testimony had been transcribed, most of the cases were settled.
When the report was made public, a headline in The Washington Post hailed it as a “Benchmark Victory for Sound Science,” and an editorial in The Wall Street Journal announced that “reason and evidence have finally won out.” And it is not only those whose sympathies lie with defendant companies in danger of being bankrupted by baseless tort claims who welcome the idea; so do the many scientists impatient with what they see as lawyers’ pointless wrangling over well-known scientific facts. Indeed, where mass torts involve vast numbers of litigants on the same issue, where the science concerned is especially complex, and where hired scientific guns are entrenched on both sides, court-appointed experts may well be the best way to reach the right upshot (and more uniform results than the kind of legal lottery in which some plaintiffs win huge awards and others nothing)–especially if judges learn from Judge Pointer’s experience about the pitfalls of choosing scientists to advise them, and about instructing those scientists on recordkeeping, conflict of interest, etc.
The Pointer Panel
Still, though the conclusion the Pointer Panel reached was almost certainly correct, it is troubling to think that just four scientists – all of whom combined this work with their regular jobs, and one of whom revealed poor judgment, to say the least, in signing a letter, while serving on the panel, to ask for financial support for another project from one of the defendant companies – were in effect responsible for the disposition of thousands of cases. More radically than Frye’s oblique deference to the relevant scientific community – more radically even than Daubert’s (and Joiner’s and Kumho’s) extension of judges’ gatekeeping powers – reliance on court-appointed scientists departs from the adversarial culture of the common-law approach. Proponents have recognised this from the beginning: “[t]he expert should be regarded as an amicus curiae” (John Ordronaux); a court should have the power to appoint “a board of experts or a single expert, not called by either side” (Judge Learned Hand, 1901). So have contemporary critics of the practice, such as Sheila Jasanoff, who complain that it is elitist, undemocratic, a move in the direction of an inquisitorial system.
Then there are the ripple effects of those disturbing DNA exonerations, which have prompted not only renewed scrutiny of forensic laboratories, renewed concern about how line-ups are conducted and photographs presented to eyewitnesses, moves to videotape interrogations, and so on – all, surely, welcome developments – but also legislation to overcome obstacles to admitting ‘new’ evidence, i.e., the results of new DNA tests on old material. Notwithstanding the law’s traditional emphasis on (in Justice Blackmun’s words) “quick, final, and binding” solutions, some states have mandated post-conviction DNA testing, and others have extended or eliminated the statute of limitations where DNA evidence may be available.
“The basic purpose of a trial is the determination of truth,” the Supreme Court averred in a 1966 ruling. “Our system of criminal justice is best described as a search for the truth,” Attorney General Janet Reno affirmed in her introduction to the 1996 National Institute of Justice report on DNA evidence, Convicted by Juries, Exonerated by Science. So we like to think; but it would be more accurate to say that the law seeks resolutions that correspond as closely as possible to the ideal of convicting X if and only if X did it, or obliging Y to compensate Z if and only if Y caused harm to Z, given other desiderata of principle or policy: that it is worse to convict the innocent than to free the guilty; that constitutional rights must be observed; that legal resolutions should be prompt and final; that people should not be discouraged from making repairs that, if made earlier, might have prevented the events for which they are being sued; etc. We also like to think that our adversarial system (under which a jury is asked to decide, on the basis of evidence presented by competing advocates, held to legally proper conduct by a judge, whether guilt or liability has been established to the required degree of proof) is as good a way as we can find to reach the desired balance. But problems with scientific testimony oblige us to think harder both about exactly what balance is most desirable and about the best means to achieve it.
There is no question about the desirability of prompt and final legal decisions; think of totalitarian regimes where people routinely languish in jail without trial, or of Dickens’s Jarndyce v. Jarndyce. Nevertheless, if new scientific work makes it possible to establish that an innocent person has been convicted, it seems obtuse to refuse to compromise finality in the service of truth. And, while it is salutary to remember that the brouhaha over recovered memories also prompted some modifications of statutes of limitations, with DNA analysis there really is the strongest grounds for such an adaptation of the culture of the law.
Adversarial System in the US
There is no question, either, that trial by jury is a vastly superior way of getting at the truth than the trials by oath, ordeal, or combat that gradually came to an end after 1215 when the Fourth Lateran Council prohibited priests from participating in such theologically grounded tests. The adversarial system in the United States is a distant and highly evolved descendant of the first English jury trials, but it is not perfectly adapted for an environment in which key factual questions can be answered only with the help of scientific work beyond the comprehension of anyone not trained in the relevant discipline. We value trial by jury in part because we think it desirable that citizens participate in public life not only by voting but also by jury service; still, though such participation is a desirable expression of the democratic ethos, civics education for jurors hardly seems adequate justification for tolerating avoidable, consequential factual errors.
But we also value trial by jury for a more fundamental reason: the protection it affords citizens against partial or irrational determinations of fact. Court-appointed experts are no panacea, and there are both legal and practical problems to be worked out; but if, where complex scientific evidence is concerned, we can sometimes do a significantly better job of determining the truth with their help, adapting the culture of the law in this way might afford better protection, and thus better serve the fundamental goal.
Pix from the Net.