In these days of moral ambiguity and intellectual uncertainty, logical puzzles are one of the last non-trivial areas where we can say things with certainty.The formidable and famous Two Envelope Paradox is a simple but very challenging conundrum, one that the philosophers are still arguing about.
An elementary but tricky three card puzzle
The disappearing 13th man visual puzzle
Lateral thinking: a medley of short puzzles.
Bertrand's Paradox in simple probability.
Newcomb's Paradox: the philosophers are still arguing about this one.
The Monty Hall Puzzle: a difficult puzzle on probability.
The Liar's Paradox: a classical Greek paradox that tormented and inspired Bertrand Russell.
Birds of diverse feathers: a difficult multiple-choice test devised by Tad Boniecki.
A ternary duel: whom would you shoot first?
Proof that 2 = 1 and other mathematical foolishness.
U2 in a hurry: can you maximise their bridge crossing capability?
The Prisoners' Dilemma: a famous decision paradox.
The St Petersburg Puzzle: an infinitely expensive gamble.
The Sleeping Beauty Problem is a difficult but elementary problem in probability.
If all the above were too easy then have a go at the Millenium Problems.