The apparent contradiction that, although water is generally more useful than diamonds, diamonds command a higher price in the market.

A paradox about a person's expectations about the timing of a future event which they are told will occur at an unexpected time. It is based on the idea that a prisoner, told that he will be hanged on a day unknown to him, concludes that "I cannot be hanged on Friday because if I haven't been hanged by the end of Thursday then it would no longer be a surprise", and so on backwards through the week.

A paradox of deontic logic, whereby the plausible statements (i) if you murder, you ought to murder gently, (ii) you do commit murder, and (iii) to murder gently you must murder imply the less plausible statement (iv) you ought to murder.

An apparent paradox in probability theory, illustrated by various questions about the probability of a child within a family being of a particular sex.

(economics) The paradox raised by a particular (theoretical) lottery game that leads to a random variable with infinite expected value (i.e. infinite expected payoff) but nevertheless seems to be worth only a very small amount to the participants.

plural of St. Petersburg paradox

(set theory) The paradox that supposing the existence of a set of all ordinal numbers leads to a contradiction; construed as meaning that it is not a properly defined set.

A hypothetical problem dealing with the notion of infinity. Given an empty vase and an infinite supply of balls, an infinite number of steps are performed, such that at each step 10 balls are added to the vase and one ball removed from it. The question is then posed: how many balls are in the vase when the task is finished?

A philosophical problem related to Benardete's paradox, but involving countably many Grim Reapers, each of which will kill the person in question at a certain time (if still alive), taking a certain period of time to do it.

The phenomenon that people can sometimes recover more quickly from more intense emotions or pain than from less distressing experiences, tentatively attributed to the fact that only the more intense states trigger psychological defense processes.