Definition of tautology

The word "tautology" originated from the Greek words "tauto" meaning "the same" and "logos" meaning "discourse" or "reason". In the 17th century, it was first used in English to describe a statement that is always true by definition, but provides no new information. For example, "all bachelors are unmarried" is a tautology because being unmarried is a characteristic that defines being a bachelor. Initially, the term was used to criticize Aristotelian logic for relying too heavily on circular reasoning. Over time, the term expanded to include any redundant or unnecessary statement, often used to highlight errors in argumentation or to challenge overly simplistic or vacuous statements. Today, tautologies are recognized as a common fallacy in logic and rhetoric, and are often used to illustrate the importance of clear and concise communication.