Often the best way to make sure you’re being logical is to express your arguments mathematically. Early in this century, the eminent economist Alfred Marshall offered this advice to his colleagues: when confronted with an economic problem, first translate into mathematics, then solve the problem, then translate back into English and burn the mathematics.

Steven Landsburg, More Sex Is Safer Sex: The Unconventional Wisdom of Economics, New York, 2007, p. 174