Alfred Binet begins his inquiry by interrogating the traditional philosophical divide between mind and matter, arguing that ordinary distinctions vanish upon close analysis. He establishes that our knowledge of the external world is fundamentally limited to sensations, which serve as the sole intermediary between unknown material causes and our cognitive faculties. Consequently, the mechanical and kinetic theories of matter put forward by physicists must be treated merely as conceptual symbols rather than absolute reflections of underlying reality. Binet extends this rigorous scrutiny to the definition of mind, systematically dissecting sensations, images, emotions, and the act of will.
He rejects the notion that the consciousness is an immaterial spiritual substance acting independently, proposing instead that consciousness and its material object form an inseparable correlative union. Throughout the text, the author navigates between the extremes of idealism and materialism, ultimately arguing against the principle of absolute heterogeneity between physical and mental phenomena. He contends that psychological laws and the operations of reasoning share a structural continuity with the physical world, viewing cognition as an evolved instrument of biological preadaptation. Finally, Binet addresses the union of the soul and the body, critiquing spiritualism, materialism, and parallelism. He concludes by presenting a provisional working hypothesis that accounts for both the conscious and unconscious functions of the nervous system, reconciling physical determinism with the selective, revealing nature of consciousness.
