The lawsuit industry is fond of claiming that it is victimized by manufactured doubt;[1] its response has often been to manufacture consensus.[2] Doubt and assent are real psychological phenomena that are removed from the more important epistemic question whether the propositions doubted or agreed to are true, or worthy of belief.
Since at least the adoption of Federal Rule of Evidence 702, the law of evidence in federal courts, and in some state courts, has come to realize that expert witness opinion testimony must be judged by epistemic criteria. Implicit in such judging is that reviewing courts, and finders of fact, must assess the validity of facts and data relied upon, and inferences drawn, by expert witnesses.
Professor Edward Cheng has argued that judges and jurors are epistemically incompetent to engage in the tasks required of them by Rule 702.[3] Cheng would replace Rule 702 with what he calls a consensus rule that requires judges and jurors to assess only whether there is a scientific consensus on general scientific propositions such as claims of causality between a particular exposure and a specific disease outcome.
Cheng’s proposal is not the law; it never has been the law; and it will never be the law. Yet, law professors must make a living, and novelty is often the coin of the academic realm.[4] Cheng teaches at Vanderbilt Law School, and a few years ago, he started a podcast, Excited Utterances, which features some insightful and some antic proposals from the law school professoriate. The podcast is hosted by Cheng, or sometimes by his protégé, G. Alexander Nunn (“Alex”), who is now Associate Professor of Law at Texas A&M University School of Law
Cheng’s consensus rule has not gained any traction in the law, but it has attracted support from a few like-minded academics. David Caudill, a Professor of Law, at the Villanova University Charles Widger School of Law, has sponsored a symposium of supporters.[5] This year, Caudill has published another publication that largely endorses Cheng’s consensus rule.[6]
Back in October 2024, Cheng hosted Caudill on Excited Utterances, to talk about his support for Cheng’s consensus rule. The podcast website blurb describes Caudill as having critiqued and improved upon Cheng’s “proposal to have courts defer to expert consensus rather than screening expert evidence through Daubert.” [This is, of course, incorrect. Daubert was one case that interpreted a statute that has since been substantively revised twice. The principle of charity suggests that Nunn meant Federal Rule of Evidence 702.] Alex Nunn conducted the interview of Caudill, which was followed by some comments from Cheng.
If you are averse to reading law review articles, you may find Nunn’s interview of Caudill a more digestible, and time-saving, way to hear a précis of the Cheng-Caudill assault on scientific fact finding in court. You will have to tolerate, however, Nunn’s irrational exuberance over how the consensus rule is “cutting edge,” and “wide ranging,” and Caudill’s endorsement of the consensus rule as “really cool,” and his dismissal of the Daubert case as “infamous.”
Like Cheng, Caudill believes that we can escape the pushing and shoving over data and validity by becoming nose counters. The task, however, will not be straightforward. Many litigations begin before there is any consensus on one side or the other. No one seems to agree how to handle such situations. Some litigations begin with an apparent consensus, but then shift dramatically with the publication of a mega-trial or a definitive systematic review. Some scientific issues remain intractable to easy resolution, and the only consensuses exist within partisan enclaves.
Tellingly, Caudill moves from the need to discern “consensus” to mere “majority rule.” Having litigated health effects claims for 40 years or so, I have no idea of how we tally support for one view over another. Worse yet, Caudill acknowledges that judges and jurors will need expert assistance in identifying consensus. Perhaps litigants will indeed be reduced to calling librarians, historians, and sociologists of science, but such witnesses will not necessarily be able to access, interpret, and evaluate the underlying facts, data, and inferences to the controversy. Cheng and Caudill appear to view this willful blindness as a feature not a bug, but their whole enterprise works in derogation of the goal of evidence law to determine the truth of the matter.[7]
Robust consensus that exists over an extended period of time – in the face of severe testing of the challenged claim – may have some claim to track the truth of the matter. Cheng and Caudill, however, fail to deal with is the situation that results when the question is called among the real experts, and the tally is 51 to 49 percent. Or worse yet, 40% versus 38%, with 22% disclaiming having looked at the issue sufficiently. Cheng and Caudill are left with asking the fact finder to guess what the consensus will be when the scientific community sees the evidence that it has not yet studied or that does not yet exist.
Perhaps the most naïve feature of the Cheng-Caudill agenda is the notion that consensus bubbles up from the pool of real experts without partisan motivations. As though there is not already enough incentive to manufacture consensus, Cheng’s and Caudill’s approach will cause a proliferation of conferences that label themselves “consensus” forming meetings, which will result in self-serving declarations of – you guessed it – consensuses.[8]
Perhaps more important from a jurisprudential view is that the whole process of identifying a consensus has the normative goal of pushing listeners into believing that the consensus has the correct understanding so that they do not have to think very hard. We do not really care about the consensus; we care about the issue that underlies the alleged consensus. At best, when it exists, consensus is a proxy for truth. Without evidence, Caudill asserts that the proxy will be correct virtually all the time. In any event, a carefully reasoned and stated consensus view would virtually always make its way to the finder of fact in litigation in the form of a “learned treatise,” with which partisan expert witnesses would disagree at their peril.
[1] See, e.g., David Michaels, Doubt is Their Product: How Industry’s War on Science Threatens Your Health (2008); David Michaels, “Manufactured Uncertainty: Protecting Public Health in the Age of Contested Science and Product Defense,” 1076 Ann. N.Y. Acad. Sci. 149 (2006); David Michaels, “Mercenary Epidemiology – Data Reanalysis and Reinterpretation for Sponsors with Financial Interest in the Outcome,” 16 Ann. Epidemiol. 583 (2006); David Michaels & Celeste Monforton, “Manufacturing Uncertainty: Contested Science and the Protection of the Public’s Health and Environment,” 95 Amer. J. Public Health S39 (2005); David Michaels, “Doubt is their Product,” 292 Sci. Amer. 74 (June 2005).
[2] See generally Edward S. Herman & Noam Chomsky, Manufacturing Consent (1988); Schachtman, “The Rise of Agnothology as Conspiracy Theory,” Tortini (Aug. 21, 2022).
[3] Edward K. Cheng, “The Consensus Rule: A New Approach to Scientific Evidence,” 75 Vanderbilt L. Rev. 407 (2022); see Schachtman, “Cheng’s Proposed Consensus Rule for Expert Witnesses,” Tortini (Sept. 15, 2022); “Further Thoughts on Cheng’s Consensus Rule” Tortini (Oct. 3, 2022); “ Consensus Rule – Shadows of Validity,” Tortini (Apr. 26, 2023); “ Consenus is Not Science,” Tortini (Nov. 8, 2023).
[4] Of possible interest, David Madigan, a statistician who has frequently been involved in litigation for the lawsuit industry, and who has proffered some particularly dodgy analyses, was Professor Cheng’s doctoral dissertation advisor. See Schachtman, “Madigan’s Shenanigans & Wells Quelled in Incretin-Mimetic Cases,” Tortini (July 19, 2022); “David Madigan’s Graywashed Meta-Analysis in Taxotere MDL,” Tortini (June 19, 2020); “Disproportionality Analyses Misused by Lawsuit Industry,” Tortini (April 20, 2020); “Johnson of Accutane – Keeping the Gate in the Garden State,” Tortini (March 28, 2015).
[5] 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 (2023).
[6] David S. Caudill, Harry Collins & Robert Evans, “Judges Should Be Discerning Consensus, Not Evaluating Scientific Expertise,” 92 Univ. Cinn. L. Rev. 1031 (2024).
[7] See, e.g., Jorge R Barrio, “Consensus Science and the Peer Review,” 11 Molecular Imaging & Biol. 293 (2009) (“scientific reviewers of journal articles or grant applications – typically in biomedical research – may use the term (e.g., ‘….it is the consensus in the field…’) often as a justification for shutting down ideas not associated with their beliefs.”); Yehoshua Socol, Yair Y Shaki & Moshe Yanovskiy, “Interests, Bias, and Consensus in Science and Regulation,” 17 Dose Response 1 (2019) (“While appealing to scientific consensus is a legitimate tool in public debate and regulatory decisions, such an appeal is illegitimate in scientific discussion itself.”); Neelay Trivedi, “Science is about Evidence, not Consensus,” The Stanford Rev. (Feb. 25, 2021).
[8] For a tendentious example of such a claim of manufactured consensus, see David Healy, “Manufacturing Consensus,” 34 The Hastings Center Report 52 (2004); David Healy, “Manufacturing Consensus,” 30 Culture, Medicine & Psychiatry 135 (2006).
