I’ve been reading up on antitrust, and just came across Bertrand’s Paradox: that a market with two firms selling identical products will be competitive. It’s the starting point for trying to give a theory of cartels; you have to explain why the cartel members don’t fall into the trap of undercutting each other until they reach the competitive price. But as soon as I saw the name, I thought, Bertrand’s Paradox, isn’t that the one about the cartel consisting of all firms that aren’t part of a cartel?
(Bonus: There are actually three Bertrand’s Paradoxes, all named after the same guy. Not one is actually a paradox.)