Fritz Machlup

But you are asking me how did the Austrians distinguish their own economics from others in the 1920s and here is my list. One, methodological individualism. Two, methodological subjectivism. Three, marginalism. Four, individual tastes and preferences, that is, subjective valuations of goods and services determine the demand for these goods and services. Five, opportunity costs (Wieser’s law). Six — and this is something that Menger and Wieser did not accept, but in the twenties we did–the time structure of consumption and production (Bhm-Bawerk’s time preference). Now these, I would say, were the things we regarded as the most important.

— Fritz Machlup, Austrian Economics Newsletter [1980]