Paradoxes
Within any scenario where only "yes" or "no" answers are accepted, a person who we know is consistently lying would "paradoxically" be a source of truth if "yes" is sometimes the correct answer. There are many such paradoxes, the most famous being known as the liar paradox, commonly expressed as "This sentence is a lie," or "This sentence is false." The so-called Epimenides paradox ("All Cretans are liars," as stated by Epimenides the Cretan) is a forerunner of this, though its status as a paradox is disputed. A class of related logic puzzles are known as knights and knaves, in which the goal is to determine who, in a group of people, is lying and who is telling the truth.
Read more about this topic: Liar
Famous quotes containing the word paradoxes:
“This is one of the paradoxes of the democratic movement—that it loves a crowd and fears the individuals who compose it—that the religion of humanity should have no faith in human beings.”
—Walter Lippmann (1889–1974)
“Though your views are in straight antagonism to theirs, assume an identity of sentiment, assume that you are saying precisely that which all think, and in the flow of wit and love roll out your paradoxes in solid column, with not the infirmity of a doubt.”
—Ralph Waldo Emerson (1803–1882)
“The way of paradoxes is the way of truth. To test Reality we must see it on the tight-rope. When the Verities become acrobats we can judge them.”
—Oscar Wilde (1854–1900)