nLab
paradox

Paradoxes

Idea

A paradox is an example of reasoning that seems perfectly valid on first sight, but which results in a contradiction or inconsistency. For example:

The following statement is false.

The previous statement is true.

Either sentence alone seems perfectly reasonable, and could meaningfully be said in another context; but together they form a paradox. It is not just that the sentences contradict each other (in which case one or both might simply be false); but the existence of the sentences contradicts the assumption that they are meaningful at all (at least using classical logic).

Examples

From logic and foundations

From natural science

In physics:

Revised on September 11, 2013 20:37:49 by Urs Schreiber (145.116.131.249)