Tadeusz Kotarbiński, a Polish philosopher and logician, was born in Warsaw in 1886. He studied philosophy and the classics at the University of Lvov, where he obtained his doctorate in 1912. He began teaching at the University of Warsaw in 1918 and soon became perhaps the most influential philosophy teacher in Poland. His enlightened views, integrity, public spirit, and social zeal frequently brought him into conflict with established opinions and with the government, both before and after World War II. Admired by many and respected by all, Kotarbiński commanded a unique position of moral and intellectual prestige in his country. He was a member of the Polish Academy of Science and of the International Institute of Philosophy, and he was for a long time chairman of both bodies. He held an honorary doctorate from the Université Libre in Brussels and was...