INTRODUCTION

Moritz Schlick, Hans Reichenbach, Rudolf Carnap, Philipp Frank, Herbert Feigl, and Carl Hempel all studied physics at university. Relativity theory and quantum theory, the two revolutionary developments of twentieth-century physics, happily coincided with the rise and consolidation of logical empiricism. Yet the designation “philosophy of physics” was little used by the logical empiricists themselves, while, with notable exceptions, they produced little of what is currently understood under that head, viz., detailed investigations into particular aspects or interpretations of physical theories. Certainly, there are important works of Reichenbach's, a few of Schlick's, mostly from his pre-Vienna days, and one or two others, recognizably belonging to philosophy of physics. Nonetheless, it is something of an anachronism to speak of logical empiricism's “philosophy of physics”.

One reason is that logical empiricist orthodoxy allotted but a narrow window to the legitimate practice of “scientific philosophy”. Carnap's 1934 declaration that “we pursue Logical Analysis but no Philosophy” is perhaps characteristic (Carnap 1934a, 28, emphasis in original). Frank, a working physicist, warned that philosophical deliberation continually posed the threat of becoming an “opium for science” (Frank 1932, viii/1998, 11), and that the very meaning of the term “philosophy of natural science” was to be sharply demarcated from all manner of “school philosophy”.