Top banner


Science at the Bar

Jennifer Mnookin

Laws of Men and Laws of Nature: The History of Scientific Expert Testimony in England and America. Tal Golan. x + 325 pp. Harvard University Press, 2004. $49.95.

Science and law remain uneasy bedfellows. In the last decade, the Supreme Court has three times issued important rulings on how trial courts ought to evaluate expert evidence, but these cases have generated as many questions as they have answered. Lawyers, judges and experts continue to express a set of related anxieties: that credulous juries may naively succumb to "junk science" proffered by opportunistic experts; that both judges and juries, lacking specialized scientific training, may be unable adequately to evaluate complex scientific and technical information; that adversarial processes and scientific knowledge are fundamentally mismatched. As Tal Golan shows in his engaging history of expert evidence in the Anglo-American courtroom, none of these frustrations is of recent vintage, and in fact, complaints about expert testimony are nearly as old as expert testimony itself.

Laws of Men and Laws of Nature is both well written and wide-ranging, traveling from 18th-century England to early 20th-century America, from patent law to microscopy to experimental psychology. The book is not long (264 pages, plus notes), and it is, inevitably, selective. Golan does not explain how he chose what to include and what to omit. He leaves the reader curious about some subjects—chemical tests for poison identification receive only a few pages, for example, and the early forensic sciences, such as fingerprinting and handwriting identification, are entirely absent. Nonetheless, the book is an extremely able, much-needed account of the tangled, troubled connections between the world of law and the world of science.

In style, this is a straightforward narrative history. Although the footnotes reveal the range and extent of Golan's research, there is no historiographical discussion to speak of, either in the text or in the footnotes. Golan's narrative is consistent with recent research in the history and sociology of science that focuses on how sciences are shaped by and within particular cultural contexts. For example, Golan shows how the questions early microscopists asked were significantly framed by forensic needs—the desire for legal evidence that could distinguish human from animal blood colored both the technical dimensions of microscopy's research program and the microscopic community's sense of its function and purpose.

But this argument about the intermingling dimensions of scientific and legal knowledge-production is largely left implicit; Golan does not overtly situate his book within any of the larger theoretical debates among scholars studying the history and sociology of science. Although more reflection on how the book contributes to these broader debates would have been helpful, there are some advantages to Golan's decision: It increases the book's readability, and it shows off his fine narrative skills.

The opening chapter, one of the most successful, traces the actual history behind an iconic 18th-century case, Folkes v. Chadd, concerning whether a man-made embankment was the cause of the decay of Wells Harbor in Norfolk, England. This case has gone down in evidence treatises as an origin story of sorts for the received history of the partisan expert witness, and is often cited as the first case in which parties were allowed to call their own experts and the first in which experts were allowed to testify not only to facts but to opinions. Golan effectively debunks both of these myths, showing first that party-controlled expert evidence was already accepted, and further, that the witnesses in Folkes v. Chadd did not merely provide their conclusory opinions but had spent much time writing detailed reports based on firsthand investigation and observation. Golan's historical skills are at their best here, as he weaves together both the scientific and legal dimensions of previously untold elements of the history of the case. He shows, for example, how epistemological debates within emerging scientific communities played out as the parties' experts were pitted against each other—natural philosophy on one side and a more practically oriented empiricism on the other.

Golan trained as a historian of science, and it shows to good effect both in this and later chapters. When he details the history of forensic microscopy, he describes the technical debates clearly and succinctly, showing, for example, how the fledgling professional community responded to concerns about the standardization of instruments and measurement problems. Golan generally takes seriously both the legal and scientific dimensions of his topic, but occasionally he privileges the scientific over the legal, taking us further inside the scientists' debates than those of the lawyers, judges and legal commentators.

In the microscopy chapter, for example, we learn that the scientific establishment largely rejected the idea that human blood corpuscles could be sufficiently distinguished from those of other mammals to allow for definitive testimony about whether a bloodstain (found, say, on the clothing of a suspect) was of human origin. But some experts nonetheless regularly testified about this issue in court. Golan effectively describes the ongoing controversies among the leading microscopists. They struggled over issues of standardizing microscopes, worried about inter­species and intraspecies variation in the size of blood corpuscles, and wrestled with philosophical concerns about how confident they ought to be before ethics permitted allowing an opinion in the court of law. But the legal details are largely missing. We do not learn, for example, what those experts who did testify actually said. Did they claim certainty, or merely articulate the possibility that the bloodstain was human? Were they ever cross-examined effectively, and if so, how? Did leading experts testify for the defense in response, arguing that definitive identification of human blood was not scientifically plausible? Similarly, Golan reports that in England, by 1875 courts were permitted to hear civil cases without a jury when complex technical evidence was at issue, but we are not told anything about how this institutional change took place, the extent to which judges exercised this power or what consequences resulted.

Although Golan frequently references the legal system's anxiety over expert charlatans and opportunists whose testimony was unduly colored by partisan allegiances, this leitmotif remains somewhat underdeveloped in his actual case studies. In his generally sympathetic account of the struggles among emerging scientific professionals, such as microscopists, radiologists and chemists, we are not provided with concrete examples of experts whose testimony so far exceeded the bounds of reputable scientific knowledge as to justify the frequent harsh ­critiques put forth by lawyers—fears of "liars, damned liars, and experts." Was, then, this intense anxiety justified? Were there in fact many charlatans who would say anything for the right price? Or did the legal vitriol stem more from legal misunderstandings about the nature of science than from the prevalence of unethical experts? Golan's book illustrates but does not fully explain an intriguing rhetorical mismatch between the enormous skepticism expressed by legal commentators and the internal debates of the expert communities.

Throughout the 19th century, judges saw their screening role for scientific expertise as extremely limited. Generally they evaluated only the credentials of the expert, not the substance of the testimony. This changed, in Golan's account, with the advent of the polygraph, which was seen to threaten legal fact-finding processes and even legal autonomy, because it suggested substituting the judgment of an expert, or still worse, a machine, for the judgment of a jury. According to Golan, the famous 1923 Frye test became the wedge through which scientific evidence began to get more substantive scrutiny, a trend that has continued and accelerated up to the present. Indeed, in his final chapter and his epilogue, Golan suggests that the story of the reception of expert evidence is a tale of an increasingly "exclusionary spirit," a growing distrust that has led to the increased scrutiny and control of scientific information by the judiciary.

Golan is surely right as far as he goes, but his conclusion misses out on certain ironies. Although judicial gatekeeping over expert evidence has indeed increased since the early 19th century, the justification for the increased scrutiny is precisely an increased recognition of how critically important expert evidence is within the legal sphere. The sometimes awkward efforts to evaluate and to exclude invalid expert testimony, as required by the aforementioned trilogy of recent Supreme Court rulings, is born precisely out of a yearning to make the "laws of men" more consistent with the "laws of science." Whether the yearning is admirable or misplaced, feasible or unrealistic, remains an open question. But the impulse behind the increased scrutiny of expert evidence is assuredly faith in science, not its opposite.

These criticisms should not detract from Golan's accomplishment: He has written the first book-length history of expert evidence in common-law courts, and it is an impressive achievement. Golan shows remarkable comfort with both legal and scientific discourse—an ability that rather dramatically distinguishes him from the subjects about whom he writes: lawyers and scientists who consistently reveal grave discomfort, miscomprehension and even downright hostility when confronted with each other. Both lawyers and scientists alike would be well served by reading this account of their shared past.

comments powered by Disqus


Bottom Banner