Thorstein Bunde Veblen

(Norwegian-American sociologist and economist, 1857–1929). Veblen was the founder, along with John R. Commons, of the Institutional economics movement. He is most famous for his book The Theory of the Leisure Class (1899), a satirical critique of the American economy in which the now conspicuous concepts of "conspicuous consumption", "conspicuous leisure" and "conspicuous waste" were introduced. Unlike the neoclassical economics that was emerging at the same time, Veblen described economic behavior as socially rather than individually determined and saw economic organization as a process of ongoing evolution.

Paul Johannes Tillich

(German-born American theologian and philosopher, 1886–1965). Tillich was one of the most influential Protestant theologians of the twentieth century, particularly after World War II. A popular speaker and preacher, Tillich is best known for his "method of correlation", a systematic theology that sought fresh Christian answers to the deep existential questions of the age. He is the author of The Protestant Era, Systematic Theology (three volumes), The Courage to Be, and Dynamics of Faith.

Henry David Thoreau

(American naturalist and writer, author of "Resistance to Civil Government", 1817–1862).

Alfred Tarski

(Polish-born American logician, mathematician, and philosopher of logic, 1902–1983). Author of Logic, Semantics, Metamathematics. Tarski is famous for his investigations, conducted in the 1930s while still in Poland, into the notions of truth and consequence, the results of which profoundly influenced later analytic philosophy.

Leo Strauss

(German-born Jewish-American political philosopher; 1899–1973). Strauss asserted that political philosophy began with the execution of Socrates by the State.

Wilfrid Stalker Sellars

(American philosopher, 1912–1989). One of the great systematic philosophers of his generation; author of Empiricism and the Philosophy of Mind (in which he concludes that classical empiricism is a myth) and Philosophy and the Scientific Image of Man.

John Rogers Searle

(American philosopher, 1932–). Searle is a prominent and often controversial contributor to philosophy of language and philosophy of mind; he is also noted for the account of social reality he gives in The Construction of Social Reality (1997). Searle's books are written in a clear, conversational style, a factor that contributes to his wide readership among lay-people. His early work was in speech act theory, where he elaborated and contributed new elements to John Austin's work in the field. Searle's philosophy of mind comprises three major components: a critique of computationalism and strong AI (the "Chinese Room Argument"), a theory of intentionality, and a theory of consciousness. Searle believes consciousness to be defined by first-person subjective experience, and thus irreducible to third-person objective description (based on neural states, for example); to attempt such a description is to immediately jettison the subject under consideration (consciousness). Searle also supposes consciousness to be an emergent property of brain processes and a function of brain biology. Searle's books include Intentionality: An Essay in the Philosophy of Mind (1983), The Rediscovery of the Mind (1992), The Mystery of Consciousness (1997), Rationality in Action (2001), and Mind: A Brief Introduction (2004).