In college, except for the obligatory courses, I avoided science, math, and accounting - all the normal preparations for business. I was on the arts side of school, and along with the usual history, psychology, and political science, I also studied metaphysics, epistemology, logic, religion, and the philosophy of the ancient Greeks [at Boston College].
As I look back on it now, it's obvious that studying history and philosophy was much better preparation for the stock market than, say, studying statistics. Investing in stocks is an art, not a science, and people who've been trained to rigidly quantify everything have a big disadvantage. If stockpicking could be quantified, you could rent time on the nearest Cray computer and make a fortune. But it doesn't work that way. All the math you need in the stock market (Chrysler's got $1 billion in cash, $500 million in long-term debt, etc.) you get in the fourth grade.
Logic is the subject that's helped me the most in picking stocks, if only because it taught me to identify the peculiar illogic of Wall Street.
One Up On Wall Street. Peter Lynch (New York: Simon and Schuster, 2000), p. 49-50.