In rhetoric, a tautology is an argument or proposition which is self-proving. The claim as stated is logically irrefutable (cannot be wrong). This hides the lack of evidence or valid reasoning supporting the conclusion.
In effect, the meaning is repeated, usually in terms which appear to be different. It is not just repetition. Repetition intended to emphasize a certain aspect of the word does not count as a tautology. For example, saying "free gift" may not be a tautology if the speaker wishes to emphasize that there are no terms and conditions, no fine print, and that he does not wish anything in return. Generally, unintentional and redundant repetition is considered a tautology.
Basically, it is saying the same thing twice, but you might say it using different words, i.e. You might say "We are reversing backwards". This is tautology because you have already said that you are moving backwards, but it has been repeated mistakenly.
Sometimes, the tautology is not easy to see,
- Because it is part of an acronym; examples HIV Virus (The V in HIV stands for virus), RAID array (The A in RAID)
- Because languages are different: examples Sahara desert (Sahara means desert)
More examples[change | change source]
- The Tenth Amendment to the US Constitution: In New York v. United States, Supreme Court Justice Sandra Day O'Connor stated, "The Tenth Amendment likewise limits the power of Congress, but this limit is not derived from the text of the Tenth Amendment itself, which, as we have discussed, is essentially a tautology". O'Connor reasoned that the Tenth Amendment repeated what was already in the structure of the Constitution. When the States consented to the Constitution they expressly delegated certain powers to the Federal government. What was not given was necessarily retained by the states.
- The phrase "A is A", often mistakenly attributed to Aristotle, was a favorite of Ayn Rand. The idea frequently appears in her philosophy, especially as written in her novel Atlas Shrugged.
- The phrase A is B because A is B.
- In his book Mostly Harmless, Douglas Adams used the phrase, "Anything that happens, happens. Anything that in happening causes something else to happen, causes something else to happen. Anything that in happening happens again, happens again. Though not necessarily in that order."
- In Sunni interpretation of the first half of the shahada, the Islamic profession of faith may be translated as "...there is no god but God." The entire Islamic faith, some Muslims contend, can be derived from the deep contemplation of this apparent tautology. However the shahada is uttered in the Arabic language, fluent speakers of which understand the difference between "god" (Ilah إلاه; often translated as meaning "deity [worthy of worship]") and "God" (Allah الله; the standard Arabic word for "[the one] God").
- Richard B. Frank's recent history of the end of the Pacific War is titled Downfall: The end of the Imperial Japanese Empire. By definition, an empire is imperial.
- Comedian Mitch Hedberg joked about a tautological advertisement for a boxing match: "It said, It's a fight to the finish! (pause) That's a good place to end."
- The TV Show NCIS Was originally going to be called Naval NCIS. NCIS stands for Naval Criminal Investigative Service.