Today is the 142nd birthday of famous philosopher/mathematician Bertrand Russell. He is the one who undermined the indisputability of logic by posing his famous Paradox, which I drew in my book Science: a Discovery in Comics as follows:
If you really want to get into Bertrand Russell though, you should read Logicomix, which is an excellent graphic novel about Russell’s life and work, as well as about the making of a graphic novel about logic.

The point of Russell’s Paradox is that it is unsolvable, and therefore questions the base of logic – but if this were a riddle, I’d answer that the barber must be a woman.
(which goes to prove, I guess, that in the nineteenth century the idea of a woman shaving men’s beards went against all logic)