In philosophy and logic, the liar paradox or liar's paradox (pseudomenon in Ancient Greek) is the statement "this sentence is false." Trying to assign to this statement a classical binary truth value leads to a contradiction (see paradox).
If "this sentence is false" is true, then the sentence is false, which would in turn mean that it is actually true, but this would mean that it is false, and so on ad infinitum.
Similarly, if "this sentence is false" is false, then the sentence is true, which would in turn mean that it is actually false, but this would mean that it is true, and so on ad infinitum.
Read more about Liar Paradox: History, Explanation of The Paradox and Variants, Logical Structure of The Liar Paradox, In Popular Culture
Famous quotes containing the words liar and/or paradox:
“The trouble with lying and deceiving is that their efficiency depends entirely upon a clear notion of the truth that the liar and deceiver wishes to hide. In this sense, truth, even if it does not prevail in public, possesses an ineradicable primacy over all falsehoods.”
—Hannah Arendt (1906–1975)
“The conclusion suggested by these arguments might be called the paradox of theorizing. It asserts that if the terms and the general principles of a scientific theory serve their purpose, i. e., if they establish the definite connections among observable phenomena, then they can be dispensed with since any chain of laws and interpretive statements establishing such a connection should then be replaceable by a law which directly links observational antecedents to observational consequents.”
—C.G. (Carl Gustav)