Carl Hempel (1905-1997) was one of the best-known philosophers of science in the latter half of the 20th century, and his account of explanation is one of the things for which he is best known. We will be spending two days on it. This assignment concerns explanation in the physical sciences; on Wed. we will look at Hempel’s argument that the same model of explanation applies in other areas, in particular to historical explanation.

Hempel’s collaborator, Paul Oppenheim (1885-1977), has an unusual biography: he was a chemist and businessman who left business in his late 40s—this was in the early 1930s when the Nazis came to power—and, for the rest of his life—more than 40 years—lived as an independently wealthy scholar, who was a friend of philosophers and scientists—among them, Einstein—and who offered support to younger scholars, like Hempel, who collaborated with him on philosophical work.

The account of explanation that Hempel and Oppenheim describe is commonly referred to as the “deductive-nomological” or “D-N” model of explanation. That label reflects the fact that it accounts for explanation in terms of deduction and laws (nomological means something like ‘relating to laws’). The key thing you need to do in reading §§1-3 is to see how Hempel does try to account for explanation in those terms (and, of course, whether you think he succeeds).

The other portion of the paper we will discuss (i.e., §6), concerns the idea of a law. Hempel and Oppenheim will begin with the idea of a generalization and attempt to add just the right further requirements to capture laws in the sense required for his account of explanation. You should follow his efforts and consider whether he succeeds.

(You might take some things the authors say about the common use of the term ‘law’ with a grain of salt. For example, what he refers to as “Bode’s general formula” is in fact commonly referred to as “Bode’s law” or “the Titius-Bode law” even though it is not commonly believed to be true and perhaps not even “law-like” in the sense Hempel discusses. Incidentally, it’s worth looking up Bode’s law on line; it is a good example to have mind in connection with a number of issues.)