Psychophysical Problem

in the broad sense, the question of the relation of mental phenomena to physical phenomena; in the narrow sense, the question of the correlation between mental and physiological (neurohumoral) processes.

In ancient Greek natural philosophy, attempts were made to prove that the psyche is dependent on external nature and the life of the body. The psychophysical problem was intensively taken up in more recent times, when 17th-century philosophy adopted a mechanistic view of the world and mental phenomena came to be regarded as inseparable from the body and subordinate to laws that hold for the entire universe. Two versions of a solution to the psychophysical problem that appeared in the 17th century greatly influenced subsequent philosophical and scientific thought; the psychophysical interaction of R. Descartes and the psychophysical parallelism of G. W. von Leibniz. According to Descartes, a living body is something of a machine, whereas consciousness (thought, volition), a substance distinct from the body, is both influenced by the body (in sensations, emotions, and so on) and capable of acting on it (in a volitional effort, for example).

The theory of the interaction of the mental and the physical was rejected by those who believed in the inseparability of consciousness and the brain, both from the idealist (Leibniz, N. de Malebranche) and materialist (D. Hartley) standpoints. The idea of interaction was contrasted with the principle of parallel occurrence of mental and physical processes. This principle became very popular in the 19th century, when the discovery of the law of the conservation of energy made it impossible to regard consciousness as a special force capable of changing the behavior of the organism at will. Moreover, Darwinism required the psyche to be regarded as an active factor regulating the vital processes. This requirement was erroneously reflected in new versions of psychophysical interaction formulated by W. James. According to Mach’s interpretation, which became widespread in the late 19th and early 20th centuries, the soul and body are constructed from the same elements (sensations); one must therefore speak not of the relations between real processes—physiological and mental—but about different complexes of sensations. This idealist conception was criticized by V. I. Lenin in his Materialism and Empiriocriticism.

Dialectical materialism solves the psychophysical problem by treating the psyche as an active reflection of reality that arises during the interaction of highly organized living systems with the external world. The psyche is inseparable from this process, in which it performs a regulatory function.