Content-Type: text/html

# Liar paradox

HomePage | RecentChanges | Preferences
You can edit this page right now! It's a free, community project

The liar paradox, attributed to the Greek philosopher [Eubulides of Miletus]? who lived in the fourth century BC, is the statement

  I am lying now.

or more succinctly

  This statement is false.

As opposed to the Epimenides paradox, this is a true paradox: assuming that the statement is true, then it must be false; assuming it is false, then it must be true. No truth value can be consistently assigned to the statement.

The proof of Goedels Incompleteness Theorem essentially consists in a formally correct formulation of a variation of this paradox in the context of a sufficiently strong [axiomatic system]?.

To avoid having a sentence refer to its own truth value, one can also construct the paradox

  The following sentence is true.
  The preceding sentense is false.

HomePage | RecentChanges | Preferences
You can edit this page right now! It's a free, community project
Edit text of this page | View other revisions
Last edited August 2, 2001 5:36 pm (diff)
Search: