What is usually understood by proponents and critics alike as orthodox Marxian economic determinism has been officially repudiated in Soviet Russia since 1929, when the continuity of a voluntarist historical theory with Marxian ideas was deliberately stressed by Stalin. This was possible because Marxism "is shot through with dualism." Marxian determinism had, previous to the Stalin era, been qualified in three basic ways: 1) by Lenin's assertion that consciousness and willful action could decisively alter social circumstances; 2) by Engels's analysis of the operation of individual wills and the essentially "statistical nature of the laws of social causation"; 3) by Engels's underscoring of the notion that the revolution is a "leap to freedom.