# Tautology A **tautology** is something where by definition you cannot derive any interesting conclusions. For instance, $A=A$ is a tautology because you gain nothing from that statement—it is empty. A tautology has zero [Logical Content](Logical%20Content.md). In a logical sense, a tautology is a statement that’s true in all possible worlds—it can’t possibly be false, because it’s true by virtue of its *structure*, not its *content*. In a broader, philosophical or conceptual sense, a tautology is a statement where the predicate is contained in the subject. It doesn’t tell you anything new — it just unpacks the concept. --- Date: 20250102 Links to: Tags: References: * []()