begin with an observation about the world and proceed to the formula-tion of an hypothesis to explain that observation; this is followed by the performance of experiments and the collection of data to test the hypothesis, and finally by a lengthy process of peer review, publication, and attempts by other researchers to replicate the experiment. Out of this process grows consensus within the scientific community.

As one brief filed in Daubert suggested, “Scientific methodology today is based on generating hypotheses and testing them to see if they can be falsified; indeed, this methodology is what distinguishes science from other fields of human inquiry.”13 This statement is followed in the Daubert opinion by a quote from Karl Popper, another eminent philosopher of science, who wrote in the 1930s: “[T]he criterion of the scientific status of the theory is its falsifiability or refutability or testability.”14

Chief Justice Rehnquist was sufficiently perplexed by this assertion to offer a mild dissent: “I defer to no one in my confidence in federal judges, but I’m at a loss to know what is meant when it is said that the scientific status of a theory depends on its falsifiability, and I expect some of them will be confused, too.15

Workshop participants found no problem with refutability, or test-ability. Scientific experiments are published publicly for the purpose of offering others the chance to replicate the results of the experiment and either to refute them or confirm them. They did discuss the notion of falsifiability at some length, however, as a concept that was produced by philosophers of science in the 1930s, 1940s, and 1950s, but which has been incorporated into more sophisticated conceptions of science today.


Several participants discussed the common public perception that scientists sometimes offer bad or “pseudo” science as evidence in the courtroom. A scientist at the workshop emphasized several reasons for this perception. He said that at one extreme of an imaginary spectrum are the “hard” sciences, such as molecular biology, physics, and chemistry. At the other end of the spectrum are the “pseudo-sciences,” such as astrology and numerology. In the middle, he said, are many topics whose


Green, “Expert Witnesses and Sufficiency of Evidence in Toxic Substances Litigation: The Legacy of Agent Orange and Bendectin Litigation,” 86 Nw. U. L. Rev. 643 (1992), cited in Daubert amici curiae brief of Nicolaas Bloembergen et al.


K. Popper, “Conjectures and Refutations: The Growth of Scientific Knowledge,” 37 (5th ed. 1989).


Daubert, 61 U.S.L.W. at 4811.

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