The ascendancy of French political power supported literary success and scientific achievement. Investigators such as Lagrange, Laplace, and Lavoisier gave mathematical and empirical support to modern chemistry, physics, and biology. In parallel, philosophical discourses on psychology led to a reinterpretation of Descartes’ formulation to focus on sensation. Condillac, Bonnet, and La Mettrie argued for the equation of mental operations and sensory input, with the result that they reduced psychology to sensation. Helvétius and Cabanis attempted to back off from such extremism by asserting the mediating role of a central ego, although both remained committed to sensory physiology. Biran and Comte recognized the consequences of reducing psychology to mere sensory physiology, but each worked out separate solutions. Biran rejected sensationalism as inadequate, suggesting an individual psychology based on consciousness and the will. In contrast Comte ultimately accepted sensationalism and dismissed psychology. For him, the individual person should properly be studied by physiology; the individual behaving in a group is the province of sociology. Comte, however, advocated a spirit of objective observation that was eventually useful to psychology. Thus, the successors to Descartes in France left psychology in a somewhat tenuous position, removed from recognition as a formal discipline.

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