ABSTRACT
The search for scientific “truth” regarding the causes of human disease is a laborious multistep process, a winnowing of a large number of postulated hypotheses down to the few that can be supported with data derived from testing and observation. Success depends on the replication of
results, coherence of evidence from many different fields, and, ultimately, an understanding of the underlying biological mechanisms of action. In evaluating the potential human health effects of chemical exposures, three major sources of scientific information are used by the courts, various government agencies, and the larger scientific community: experimental laboratory research, controlled
or thought; nonetheless, each makes a unique contribution toward understanding the etiologies of human disease and each has certain inherent limitations. Ultimately, the determination of causation depends on the demonstration of a meaningful elevated risk for the disease among those with the “exposure” and a biological explanation for the excess. The former can only be obtained via epidemiology studies; the latter usually comes from an interplay of information derived from experimental laboratory research and controlled clinical investigations.
