Ludwig Josef Johann Wittgenstein (26 April 1889 — 29 April 1951) was an Austrian-British philosopher who worked primarily in logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language.Described by Bertrand Russell as "the most perfect example I have ever known of genius as traditionally conceived, passionate, profound, intense, and dominating", he helped inspire two of the twentieth century's principal philosophical movements: the Vienna Circle and Oxford ordinary language philosophy. According to an end of the century poll, professional philosophers in Canada and the U.S. rank both his Tractatus Logico-Philosophicus and Philosophical Investigations among the top five most important books in twentieth-century philosophy, the latter standing out as "...the one crossover masterpiece in twentieth-century philosophy, appealing across diverse specializations and philosophical orientations". Wittgenstein's influence has been felt in nearly every field of the humanities and social sciences, yet there are widely diverging interpretations of his thought.
