From the Reference Guide to Epidemiology of the Federal Judicial Center’s Reference Manual on Scientific Evidence, the principal reference for instructing US courts in regard to epidemiology. The Manual states: “…epidemiology cannot objectively prove causation; rather, causation is a judgment for epidemiologists and others interpreting the epidemiological data.” , and “.. the existence of some [associated] factors does not ensure that a causal relationship exists. Drawing causal inferences after finding an association and considering these factors requires judgment and searching analysis.”  and “[w]hile the drawing of causal inferences is informed by scientific expertise, it is not a determination that is made by using scientific methodology.”.
Thus, while epidemiologists insist that their discipline is a science, clearly it is not the solid experimental science that produces reliable causal connections to fuel new scientific discoveries, successful technological advances, and defensible public health policies. More to the point, if multifactorial epidemiology does not operate in the framework of science, what warrants of reliability could it offer?
It remains a fact that in over 50 years of trying to induce cancer in animals using tobacco smoke, not even one study has yielded a statistically significant result that links cancer to tobacco use
Although there is substantial evidence of the health benefits of moderate drinking, there has been a continued campaign on the part of many alcohol opponents to suppress or deny these findings. For instance, Harvard epidemiologist Carl Seltzer, a co-investigator on the Framingham study, found positive effects of moderate drinking on heart disease 25 years ago. Seltzer was denied permission to publish these results by the US National Heart and Lung Institute on the grounds that an article about such results would be “scientifically misleading and socially undesirable in view of the major problem of alcoholism that already exists in the country.” (C. Seltzer, Journal of Clinical Epidemiology 1997 50: 627-629, “Conflicts of Interest” and “political science”)