MOLESCHOTT, JAKOB. – Dutch physiologist and physician, b. in s-Hertogenbosch on 9 April 1822, d. in Rome on 20 May 1893. He first taught in Heidelberg (1847–54), where he was opposed because of his materialistic orientation, and then in Zurich. There, having become known to F. De Sanctis, Minister of Education, he was appointed professor at the University of Turin (1861); he subsequently taught in Rome (from 1879). He was a senator of the Kingdom of Italy.
He conducted scientific research on the phenomena of nutrition and metabolism in plants and animals (Physiologie des Stoffwechsels in Pflanzen und Tieren, Erlangen 1851; Untersuchungen zur Naturlehre des Menschen und der Tiere, 13 vols., Frankfurt, then Giessen 1857–85),
etc., and on human physiology (the theory of cardiac innervation). His fundamental work Der Kreislauf des Lebens (Maganza 1852) marks the transition from the philosophy of nature, inspired by Romanticism, to the materialistic conception of the world as a system of force and matter, in which M. influenced Büchner (v.). Unlike the dogmatic materialists, M. still admits with Kant that the space and time in which the world presents itself are subjective; but their content, the substance concealed between physical phenomena and psychic phenomena, is for him matter, not spirit. Consciousness itself has the brain as its organ, nor does it possess any reality apart from II. The material world is governed by a continuous circulation of forces, of the various types and orders of existence, which assist one another and transform into one another. Thus the reciprocal relations between nature and society, between race and environment, preserve man’s life. These quite naïve views were compared by contemporaries to the scholastic metaphysics of substances and to medieval hylomorphism (v.): but they do not transcend the materialistic method.