This article focuses on the influence of American-born modern dancer, Isadora Duncan, on modernist performance. In her 1927 autobiography, Duncan declares that she must place a motor in her soul before every performance and she consistently positions her choreography at the juncture of motorized movement and soulful expression. Her efforts to reimagine spirit through machine processes are shared by many key figures of modernism, including the Russian director Constantin Stanislavski, but her influence on modernist performance has not been recognized. Her theories are dismissed, primarily due to her use of terms associated with Victorianism (soul, inner self, and human spirit). Duncan's conjuncture of metaphysical and materialist thought is actually a dominant feature of twentieth-century art, shared by such diverse movements as Italian futurism, the Moscow Art Theatre's innovations in drama, Greenwich Village Radicalism, and U.S. feminism. Duncan repeatedly figures her fundamental movement principles through the symbol of the motor. First, the motor's ability to move several objects suggests the possibility of representing a multiplied body, an interest she shared with several futurists. The constant, tireless motion of the motorized machine also offers the ideal of continuous dance movements that appear to be executed effortlessly, without the intervention of the will, a concept she derives from Friedrich Nietzsche.