Simplistic claims about the objectivity of science have been challenged from a variety of perspectives. Evaluation of the external context of production of knowledge and the methodological approaches to posing questions and assembling evidence shows that there is no pure "science"; rather, all scientific knowledge is shaped by the social history of its production. Examples are given of how quantitative concepts in modern epidemiology influence the recognition of the causes of disease. The author uses the phenomenon of intensive swine production by vertically integrated agribusiness to illustrate how broad problems such as environmental racism, agricultural determinants of nutrition, loss of natural resources, and conditions conducive to emergence of new diseases are hidden by epidemiological approaches that fit into corporate policy perspectives. It is critically important to ask who produces epidemiological knowledge, and whose health is promoted by that knowledge.