This paper focuses on causation evidence in toxic-tort litigation, and makes two main arguments, the first epistemological and the second legal. The epistemological argument is that, under certain conditions, a congeries of evidence warrants a conclusion to a higher degree than any of its components alone would do; the legal argument, interlocking with this, is that our evidence law encourages a kind of atomism that can actually impede the process of arriving at the conclusion most warranted by the evidence–an atomism the effects of which have been especially salient to causation evidence in toxic-tort cases.

§1 will set the stage by looking at two cases where the epistemological issue to be tackled here came explicitly to courts’ attention; §2 will develop the epistemological argument, first in a general form, and then as it applies to the kinds of causation evidence typically encountered in toxic-tort litigation; §3 will rely on this account to answer some of the epistemological questions about causation evidence that have been at issue in such cases; and §4 will develop the legal argument, showing that, ironically enough, Daubert’s requirement that proffered expert testimony is admissible only if it is reliable may sometimes stand in the way of an adequate assessment of the reliability of causation evidence.