Have any of you ever heard of the two-envelope paradox? It’s a paradox so important that Wikipedia manages to have two articles on it: Two envelopes problem and Envelopes paradox. The only thing that puzzles me about it is that I’m having trouble seeing how it’s a paradox — unlike, say, the Monty Hall problem, the naive answer is the correct one.

An easy-to-read article on mathematics in biology.