 Although some contemporary philosophers have argued that Mill’s method a priori is largely defensible (Bhaskar 1975, Cartwright 1989, and Hausman 1992), by the middle of the Twentieth Century Mill’s views appeared to many economists out of step with their understanding of contemporary philosophy of science. Without studying Mill’s text carefully, it was easy for economists to misunderstand his terminology and to regard his method a priori as opposed to empiricism. Others took seriously Mill’s view that the basic principles of economics should be empirically established and found evidence to cast doubt on some of the basic principles, particularly the view that firms attempt to maximize profits (Hall and Hitch 1938, Lester 1946, 1947). Methodologists who were well-informed about contemporary developments in philosophy of science, such as Terence Hutchison (1938), denounced “pure theory” in economics as unscientific.