> Probability-wise I just mean there's a 2/8 chance that it's one of these pawns. Right—there's a 2 in 8 chance that the assassin is one of those pawns, and a

> Probability-wise I just mean there's a 2/8 chance that it's one of these pawns. Right—there's a 2 in 8 chance that the assassin is one of those pawns, and a 1 in 2 conditional probability, given that one of them is the assassin, that the one you pick is the assassin; so, by 'deconditioning', a 1 in 8 chance overall. (I think it might make this more plausible—just in terms of probability, not a better rule—to imagine that the rule is changed so that the assassin has to be one of the pawns who can check the king. Then the probability of one of those pawns being the assassin is 100%, by fiat; but you've still only got a 50% chance of picking that one.)