But I know I had a growing feeling in the later years of my work at the subject that a good mathematical theorem dealing with economic hypothesis was very unlikely to be good economics: and I went more and more on the rules – (1) Use mathematics as a shorthand language, rather than as an engine of inquiry. (2) Keep to them till you have done. (3) Translate into English (4) Then illustrate by examples that are important in real life (5) Burn mathematics (6) If you can’t succeed in 4, burn in 3.

–Marshall wrote to Bowley, 1906

The aim of language is to say something — and not merely about the language itself. Mathematical social science is, foremost, social science. If it is bad social science (i.e., empirically false), the fact that it is good mathematics (i.e., logically consistent) should provide little comfort

(Herbert A. Simon, 1954)