(set theory) A demonstration of a surprising property of infinite sets. Some positive integers are squares while others are not; therefore, all the numbers, including both squares and non-squares, must be more numerous than just the squares; yet for every square there is exactly one positive number that is its square root, and for every number there is exactly one square; hence, there cannot be more of one than of the other.

(fluid dynamics) The contradiction that, for incompressible and inviscid potential flow, the drag force is zero on a body moving with constant velocity relative to the fluid.

plural of paradox of fiction

(philosophy) The paradox that (i) people have emotional responses to fictitious events, and (ii) one must believe that something truly exists in order to be emotionally moved by it, but (iii) nobody who considers an event to be fictitious can also believe it to be real.

A paradox that occurs in naive set theory or naive logics, and allows the derivation of an arbitrary sentence from a self-referring sentence and some apparently innocuous logical deduction rules.

Synonym of Curry's paradox

(economics) A paradox of economics, stating that an increase in autonomous saving leads to a decrease in aggregate demand and thus a decrease in gross output which will in turn lower total saving: narrowly speaking, total saving may fall because of individuals' attempts to increase their saving, and, broadly speaking, increase in saving may be harmful to an economy.

plural of paradox of thrift

plural of twins paradox

plural of clock paradox