It was once widely assumed that scientific theories are comprised of laws. The laws of nature were taken to be empirical and universal, i.e., unrestricted and exceptionless. The major account that explained how things actually happened with nomothetic settings (a world governed by laws) was Hempel and Oppenheim’s (1948) nomological-deductive (D-N) model. Popper (1934/1959) outlined similar ideas. For this reason, therefore, the deductive-nomological method of explanation is also sometimes called the Popper-Hempel theory of explanation.
Later the traditional view of theories as (primary) universal laws was challenged. Many of the best candidates for laws contain too many exceptions to be called bona fide laws of nature, or they apply in ideal rather than real settings. In life sciences, cognitive science, psychology and social science, the traditional concept of law was found problematic. Then, a fundamental question is, what does the explanatory work in many sciences, if not laws?
One answer is mechanism-based explanation (MBEs). MBEs, especially in the new mechanistic philosophy, are often distinguished from law-based explanations. In this short course, professor William Bechtel discusses what are mechanisms.
About the Lecturer
Professor William Bechtel is a professor of philosophy in the Department of Philosophy and the Science Studies Program at the University of California, San Diego. He was a Professor of Philosophy at Washington University in St. Louis from 1994 until 2002 [1]. Bechtel was also the chair of the Philosophy Department from 1999 until 2002 and was heavily involved with the Philosophy-Psychology-Neuroscience program, serving at different times as Assistant Director and Director. Before that, he was at Georgia State. Bechtel earned his PhD from the University of Chicago and his BA from Kenyon College.
Bechtel's work in philosophy has focused on the philosophy of the life sciences. In particular, he has worked on cell biology, biochemistry, neuroscience, and cognitive science. Bechtel advocates a mechanistic approach to philosophy of science, taking the view that phenomena are often explained by specifying mechanisms. He argues that although this is more naturally in accordance with the actual methodology of life scientists, it contrasts with the traditional model of deduction from laws supported by mainstream philosophy of science.