This book offers a radically new interpretation of the entire philosophy of J. G. Fichte by showing the impact of nineteenth-century psychological techniques and technologies on the formation of his theory of the imagination—the very centerpiece of his philosophical system. By situating Fichte’s philosophy within the context of nineteenth-century German science and culture, the book establishes a new genealogy, one that shows the extent to which German idealism’s transcendental account of the social remains dependent upon the scientific origins of psychoanalysis in the material techniques of Mesmerism. The book makes it clear that the rational, transcendental account of spirit, imagination, and the social has its source in the psychological phenomena of affective rapport. Specifically, the imagination undergoes a double displacement in which it is ultimately subject to external influence, the influence of a material technique, or, in short, a technology.