Any philosophy that can be put in a nutshell belongs there.

Rickey’s quip is a warning against overconfident simplification. A “philosophy” is meant to grapple with complexity—human motives, ethics, uncertainty, and competing goods. If it fits neatly into a slogan, Rickey implies, it is likely too thin to guide real decisions and therefore “belongs” in a nutshell: a small, self-contained object with limited use. The line also pokes at the temptation to treat aphorisms as wisdom. In leadership and sport—domains Rickey knew well—easy formulas can sound decisive, but they often fail under pressure, where judgment requires nuance, context, and a willingness to revise one’s principles in light of reality.