Scientists have participated in a remarkable number of controversies during the past few decades. Some of these controversies revolve around technology. Legislation to control the environmental and health risks of technology calls for decisions based on “the best scientific evidence.” Government efforts to regulate advances in technology thus engage scientific experts in lively debate over the interpretation of data and the dimensions of risk. Other controversies relate to science itself. The disputes over recombinant DNA research, animal experimentation, in vitro fertilization, or fetal research have inevitably engaged scientists in political activism to protect their own interests.

Still other disputes, including many of those discussed in this volume, have little to do with science or technology at all. Abortion legislation, the decision to ban Laetrile, and the classification of homosexuality by the American Psychiatric Association as a mental disorder are fundamentally ethical, moral, or political issues. Yet, here too science is consistently invoked as the disputes unfold, reflecting the increasing tendency to rely on scientific standards as a basis for legal and policy decisions. Indeed, science is a political resource, called upon as a source of rationality and a basis of consensus in a wide range of policy areas.

Although access to expertise provides a means of legitimating decisions, it can also provide the ability to question them. Thus, controversial public policy questions invariably seem to evolve into scientific disputes, and difficult ethical dilemmas translate into debates over the adequacy and interpretation of evidence or the appropriateness of scientific methodologies.