Alabama Law Review
Judges are removing the individual plaintiffs from many torts cases, and are instead conducting fact-finding about abstract statistical individuals. But the reasoning about specific causation in those cases is often fallacious. This Article critiques the error by analyzing direct inferences from causal generalizations about groups to probabilistic conclusions about causation in individuals. It identifies six distinct types of uncertainty in such inferences: measurement uncertainty, sampling uncertainty, modeling uncertainty, causal uncertainty, uncertainty about plaintiff representativeness, and uncertainty about assigning a probability to a specific plaintiff. These six uncertainties are logically necessary to this type of inference, and are not peculiar to toxic tort cases or to particular kinds of scientific evidence. The Article argues that direct inferences about causation are warranted only if all of these uncertainties are within acceptable bounds. As a result, findings about specific causation cannot be purely factual or scientific, and should also rest on common sense, fairness, and justice, as well as on the substantive and process policies of tort law. The Article discusses various decisions involving the faulty reasoning (a products liability case alleging that third-generation oral contraceptives caused venous-thromboembolisms, medical malpractice cases posing the loss-of-chance problem, and a toxic torts case alleging injuries due to radioactive emissions), and it critiques several quantitative rules adopted using the faulty reasoning (a 0.5 inference rule for fact-finding, a greater-than-50% rule for evaluating the legal sufficiency of evidence, and certain rules of admissibility following the Supreme Court's decisions in Daubert and Kumho Tire). The Article concludes that courts should correct the central fallacy behind these decisions and rules, reject the junk logic that has wrongly driven the cases, and restore the individual plaintiff to the fact-finding process.
Vern R. Walker,
Restoring the Individual Plaintiff to Tort Law by Rejecting ‘Junk Logic’ about Specific Causation, 56 Ala. L. Rev. 381
Available at: http://scholarlycommons.law.hofstra.edu/faculty_scholarship/141