Thomas Theorem

The Thomas theorem is a proposition in sociology formulated in 1928 by William Isaac Thomas and Dorothy Swaine Thomas, stating that if people define situations as real, those situations are real in their consequences. In other words, it is a person's interpretation of a situation, not any objectively correct interpretation of it, that causes the action that follows, so that a person's subjective perception of events shapes their behavior regardless of whether that perception is accurate. Despite its name, the Thomas theorem is not a theorem in the mathematical sense, but a foundational proposition describing how belief and interpretation drive human action.