TORTINI

For your delectation and delight, desultory dicta on the law of delicts.

Consensus Rule – Shadows of Validity

April 26th, 2023

Back in 2011, at a Fourth Circuit Judicial Conference, Chief Justice John Roberts took a cheap shot at law professors and law reviews when he intoned:

“Pick up a copy of any law review that you see, and the first article is likely to be, you know, the influence of Immanuel Kant on evidentiary approaches in 18th Century Bulgaria, or something, which I’m sure was of great interest to the academic that wrote it, but isn’t of much help to the bar.”[1]

Anti-intellectualism is in vogue these days. No doubt, Roberts was jocularly indulging in an over-generalization, but for anyone who tries to keep up with the law reviews, he has a small point. Other judges have rendered similar judgments. Back in 1993, in a cranky opinion piece – in a law review – then Judge Richard A. Posner channeled the liar paradox by criticizing law review articles for “the many silly titles, the many opaque passages, the antic proposals, the rude polemics, [and] the myriad pretentious citations.”[2] In a speech back in 2008, Justice Stephen Breyer noted that “[t]here is evidence that law review articles have left terra firma to soar into outer space.”[3]

The temptation to rationalize, and to advocate for reflective equilibrium between the law as it exists, and the law as we think it should be, combine to lead to some silly and harmful efforts to rewrite the law as we know it.  Jeremy Bentham, Mr. Nonsense-on-Stilts, who sits stuffed in the hallway of the University of London, ushered in a now venerable tradition of rejecting tradition and common sense, in proposing all sorts of law reforms.[4]  In the early 1800s, Jeremy Bentham, without much in the way of actual courtroom experience, deviled the English bench and bar with sweeping proposals to place evidence law on what he thought was a rational foundation. As with his naïve utilitarianism, Bentham’s contributions to jurisprudence often ignored the realities of human experience and decision making. The Benthamite tradition of anti-tradition is certainly alive and well in the law reviews.

Still, I have a soft place in my heart for law reviews.  Although not peer reviewed, law reviews provide law students a tremendous opportunity to learn about writing and scholarship through publishing the work of legal scholars, judges, thoughtful lawyers, and other students. Not all law review articles are non-sense on stilts, but we certainly should have our wits about us when we read immodest proposals from the law professoriate.

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Professor Edward Cheng has written broadly and insightfully about evidence law, and he certainly has the educational training to do so. Recently, Cheng has been bemused by the expert paradox, which wonders how lay persons, without expertise, can evaluate and judge issues of the admissibility, validity, and correctness of expert opinion. The paradox has long haunted evidence law, and it is at center stage in the adjudication of expert admissibility issues, as well as the trial of technical cases. Recently, Cheng has proposed a radical overhaul to the law of evidence, which would require that we stop asking courts to act as gatekeepers, and to stop asking juries to determine the validity and correctness of expert witness opinions before them. Cheng’s proposal would revert to the nose counting process of Frye and permit consideration of only whether there is an expert witness consensus to support the proffered opinion for any claim or defense.[5] Or in Plato’s allegory of the cave, we need to learn to be content with shadows on the wall rather than striving to know the real thing.

When Cheng’s proposal first surfaced, I wrote briefly about why it was a bad idea.[6] Since his initial publication, a law review symposium was assembled to address and perhaps to celebrate the proposal.[7] The papers from that symposium are now in print.[8] Unsurprisingly, the papers are both largely sympathetic (but not completely) to Cheng’s proposal, and virtually devoid of references to actual experiences of gatekeeping or trials of technical issues.

Cheng contends that the so-called Daubert framework for addressing the admissibility of expert witness opinion is wrong.  He does not argue that the existing law, in the form of Federal Rules of Evidence 702 and 703, does not call for an epistemic standard for both admitting opinion testimony, as well for the fact-finders’ assessments. There is no effort to claim that somehow four Supreme Court cases, and thousand of lower courts, have erroneously viewed the whole process. Rather, Cheng simply asserts non-expert judges cannot evaluate the reliability (validity) of expert witness opinions, and that non-expert jurors cannot “reach independent, substantive conclusions about specialized facts.”[9] The law must change to accommodate his judgment.

In his symposium contribution, Cheng expands upon his previous articulation of his proposed “consensus rule.”[10] What is conspicuously absent, however, is any example of failed gatekeeping that excluded valid expert witness opinion. One example, the appellate decision in Rosen v. Ciba-Geigy Corporation,[11] which Cheng does give, is illustrative of Cheng’s project. The expert witness, whose opinion was excluded, was on the faculty of the University of Chicago medical school; Richard Posner, the appellate judge who wrote the opinion that affirmed the expert witness’s exclusion, was on the faculty of that university’s law school. Without any discussion of the reports, depositions, hearings, or briefs, Cheng concludes that “the very idea that a law professor would tell medical school colleagues that their assessments were unreliable seems both breathtakingly arrogant and utterly ridiculous.”[12]

Except, of course, very well qualified scientists and physicians advance invalid and incorrect claims all the time. What strikes me as breathtakingly arrogant and utterly ridiculous is the judgment of a law professor who has little to no experience trying or defending Rule 702 and 703 issues labeling the “very idea” as arrogant and ridiculous. Aside from its being a petitio principia, we could probably add that the reaction is emotive, uninformed, and uninformative, and that it fails to support the author’s suggestion that “Daubert has it all wrong,” and that “[w]e need a different approach.”

Judges and jurors obviously will never fully understand the scientific issues before them.  If and when this lack of epistemic competence is problematic, we should honestly acknowledge how we are beyond the realm of the Constitution’s seventh amendment. Since Cheng is fantasizing about what the law should be, why not fantasize about not allowing lay people to decide complex scientific issues? Verdicts from jurors who do not have to give reasons for their decisions, and who are not in any sense peers of the scientists whose work they judge are normatively problematic.

Professor Cheng likens his consensus rule to how the standard of care is decided in medical malpractice litigation. The analogy is interesting, but hardly compelling in that it ignores “two schools of thought” doctrine.[13] In litigation of claims of professional malpractice, the “two schools of thought doctrine” is a complete defense.  As explained by the Pennsylvania Supreme Court,[14] physicians may defend against claims that they deviated from the standard of care, or of professional malpractice, by adverting to support for their treatment by a minority of professionals in their field:

“Where competent medical authority is divided, a physician will not be held responsible if in the exercise of his judgment he followed a course of treatment advocated by a considerable number of recognized and respected professionals in his given area of expertise.”[15]

The analogy to medical malpractice litigation seems inapt.

Professor Cheng advertises that he will be giving full-length book treatment to his proposal, and so perhaps my critique is uncharitable in looking at a preliminary, (antic?) law review article. Still, his proposal seems to ignore that “general acceptance” renders consensus, when it truly exists, as relevant to both the court’s gatekeeping decisions, and the fact finders’ determination of the facts and issues in dispute. Indeed, I have never seen a Rule 702 hearing that did not involve, to some extent, the assertion of a consensus, or the lack thereof.

To the extent that we remain committed to trials of scientific claims, we can see that judges and jurors often can detect inconsistencies, cherry picking, unproven assumptions, and other aspects of the patho-epistemology of exert witness opinions. It takes a community of scientists and engineers to build a space rocket, but any Twitter moron can determine when a rocket blows up on launch. Judges in particular have (and certainly should have) the competence to determine deviations from the scientific and statistical standards of care that pertain to litigants’ claims.

Cheng’s proposal also ignores how difficult and contentious it is to ascertain the existence, scope, and actual content of scientific consensus. In some areas of science, such as occupational and environmental epidemiology and medicine, faux consensuses are set up by would-be expert witnesses for both claimants and defendants. A search of the word “consensus” in the PubMed database yields over a quarter of a million hits. The race to the bottom is on. Replacing epistemic validity with sociological and survey navel gazing seems like a fool’s errand.

Perhaps the most disturbing aspect of Cheng’s proposal is what happens in the absence of consensus.  Pretty much anything goes, a situation that Cheng finds “interesting,” and I find horrifying:

“if there is no consensus, the legal system’s options become a bit more interesting. If there is actual dissensus, meaning that the community is fractured in substantial numbers, then the non-expert can arguably choose from among the available theories. If the expert community cannot agree, then one cannot possibly expect non-experts to do any better.”[16]

Cheng reports that textbooks and other documents “may be both more accurate and more efficient” evidence of consensus.[17] Maybe; maybe not.  Textbooks are typically often dated by the time they arrive on the shelves, and contentious scientists are not beyond manufacturing certainty or doubt in the form of falsely claimed consensus.

Of course, often, if not most of the time, there will be no identifiable, legitimate consensus for a litigant’s claim at trial. What would Professor Cheng do in this default situation? Here Cheng, fully indulging the frolic, tells us that we

“should hypothetically ask what the expert community is likely to conclude, rather than try to reach conclusions on their own.”[18]

So the default situation transforms jurors into tea-leaf readers of what an expert community, unknown to them, will do if and when there is evidence of a quantum and quality to support a consensus, or when that community gets around to articulating what the consensus is. Why not just toss claims that lack consensus support?


[1] Debra Cassens Weiss, “Law Prof Responds After Chief Justice Roberts Disses Legal Scholarship,” Am. Bar Ass’n J. (July 7, 2011).

[2] Richard A. Posner, “Legal Scholarship Today,” 45 Stanford L. Rev. 1647, 1655 (1993), quoted in Walter Olson, “Abolish the Law Reviews!” The Atlantic (July 5, 2012); see also Richard A. Posner, “Against the Law Reviews: Welcome to a world where inexperienced editors make articles about the wrong topics worse,”
Legal Affairs (Nov. 2004).

[3] Brent Newton, “Scholar’s highlight: Law review articles in the eyes of the Justices,” SCOTUS Blog (April 30, 2012); “Fixing Law Reviews,” Inside Higher Education (Nov. 19, 2012).

[4]More Antic Proposals for Expert Witness Testimony – Including My Own Antic Proposals” (Dec. 30, 2014).

[5] Edward K. Cheng, “The Consensus Rule: A New Approach to Scientific Evidence,” 75 Vanderbilt L. Rev. 407 (2022).

[6]Cheng’s Proposed Consensus Rule for Expert Witnesses” (Sept. 15, 2022);
Further Thoughts on Cheng’s Consensus Rule” (Oct. 3, 2022).

[7] Norman J. Shachoy Symposium, The Consensus Rule: A New Approach to the Admissibility of Scientific Evidence (2022), 67 Villanova L. Rev. (2022).

[8] David S. Caudill, “The ‘Crisis of Expertise’ Reaches the Courtroom: An Introduction to the Symposium on, and a Response to, Edward Cheng’s Consensus Rule,” 67 Villanova L. Rev. 837 (2022); Harry Collins, “The Owls: Some Difficulties in Judging Scientific Consensus,” 67 Villanova L. Rev. 877 (2022); Robert Evans, “The Consensus Rule: Judges, Jurors, and Admissibility Hearings,” 67 Villanova L. Rev. 883 (2022); Martin Weinel, “The Adversity of Adversarialism: How the Consensus Rule Reproduces the Expert Paradox,” 67 Villanova L. Rev. 893 (2022); Wendy Wagner, “The Consensus Rule: Lessons from the Regulatory World,” 67 Villanova L. Rev. 907 (2022); Edward K. Cheng, Elodie O. Currier & Payton B. Hampton, “Embracing Deference,” 67 Villanova L. Rev. 855 (2022).

[9] Embracing Deference at 876.

[10] Edward K. Cheng, Elodie O. Currier & Payton B. Hampton, “Embracing Deference,” 67 Villanova L. Rev. 855 (2022) [Embracing Deference]

[11] Rosen v. Ciba-Geigy Corp., 78 F.3d 316 (7th Cir. 1996).

[12] Embracing Deference at 859.

[13]Two Schools of Thought” (May 25, 2013).

[14] Jones v. Chidester, 531 Pa. 31, 40, 610 A.2d 964 (1992).

[15] Id. at 40.  See also Fallon v. Loree, 525 N.Y.S.2d 93, 93 (N.Y. App. Div. 1988) (“one of several acceptable techniques”); Dailey, “The Two Schools of Thought and Informed Consent Doctrine in Pennsylvania,” 98 Dickenson L. Rev. 713 (1994); Douglas Brown, “Panacea or Pandora’ Box:  The Two Schools of Medical Thought Doctrine after Jones v. Chidester,” 44 J. Urban & Contemp. Law 223 (1993).

[16] Embracing Deference at 861.

[17] Embracing Deference at 866.

[18] Embracing Deference at 876.