W. I. Thomas Biography

William Isaac Thomas (August 13, 1863 – December 5, 1947) was an American sociologist. With the help of Polish sociologist Florian Znaniecki, W.I. Thomas developed innovative work on the sociology of migration. Thomas then went on to formulate a fundamental principle of sociology, known as the Thomas theorem. Through his theorem, Thomas contended that, "If men define situations as real, they are real in their consequences".