Kropotkin Petr Alekseevich (1842–1921), Russian geographer, geologist, naturalist, and philosopher, best remembered for his anarchism and his defense of mutual aid as a factor of evolution. Traveling extensively in Siberia on scientific expeditions (1862–67), he was stimulated by Darwin’s newly published theory of evolution and sought, in the Siberian landscape, confirmation of Darwin’s Malthusian principle of the struggle for survival. Instead Kropotkin found that underpopulation was the rule, that climate was the main obstacle to survival, and that mutual aid was a far more common phenomenon than Darwin recognized. He soon generalized these findings to social theory, opposing social Darwinism, and also began to espouse anarchist theory. See also ANARCHISM , DAR- WINISM , RUSSIAN PHILOSOPHY. P.T.G.