…a seemingly absurd or contradictory statement or proposition which when investigated may prove to be well founded or true…
…the apparent paradox arising from relativity theory that if one of a pair of twins makes a long journey at near the speed of light and then returns, he or she will have aged less than the twin who remains behind…
…the apparent paradox that if stars are distributed evenly throughout an infinite universe, the sky should be as bright by night as by day, since more distant stars would be fainter but more numerous. This is not the case because the universe is of finite age, and the light from the more distant stars is dimmed because they are receding from the observer as the universe expands…
…a logical paradox stated in terms of set theory, concerning the set of all sets that do not contain themselves as members, namely that the condition for it to contain itself is that it should not contain itself…
