The physical explanation of the vital processes and the rejection of Palavitalism were general in the last third of the nineteenth century. This was due most of all to the great advance in experimental physiology, which Carl Ludwig and Felix Bernard led as regards the animal body, and Julius Sachs and Wilhelm Preyer for the plant. While these and other physiologists used the remarkable results of modern physics and chemistry in the experimental study of the vital functions, and sought to determine their complicated course in terms of mass and weight and formulate their discoveries as mathematically as possible, they brought a great number of the wonders of life under the same fixed laws that were recognized in the physics and chemistry of the inorganic world. On the other hand, vitalism met with a powerful opponent in Charles Darwin, who solved, by his theory of selection, one of the most obscure biological problems, the constantly repeated question: How can we give a mechanical explanation of the orderly structures of the living being? How was this ingenious machine of the animal or plant body unconsciously produced by natural means, without supposing that some intelligent artificer or creator had deliberately designed and produced it?

The further development of Darwin's theory of selection in the last four decades, and the increasing support which has been given to the theory of descent in the great advance of ontogeny, phylogeny, comparative anatomy, and physiology, did much to establish the monistic conception of life. It took the shape more and more of a definite anti-vitalism. Hence it is strange to find that in the course of the last twenty years the old vitalism that everybody had thought dead has lifted up its head once more, though in a new and modified form.[4] This modern vitalism comprises two essentially different tendencies.

The partisans of the modern vital force are divided into two groups, which may be designated the sceptical and the dogmatic. Sceptical Neovitalism was first formulated by Bunge, of Basle (1887), in the introduction to his Manual of Physiological Chemistry. While he granted the possibility of a full explanation of one part of the vital phenomena by mechanical causes, or the physical and chemical forces of lifeless nature, he rejected it for the other half, especially for psychic activities. He insists that the latter cannot be explained mechanically, and that there is nothing analogous to them in inorganic nature; only a supra-mechanical vital force can produce them, and this is transcendental and beyond the range of scientific inquiry. Much the same was said later by Rindfleisch (1888), more recently by Richard Neumeister in his Studies of the Nature of Vital Phenomena (1903), and by Oscar Hertwig in the lecture on "The Development of Biology in the Nineteenth Century," which he delivered at Aachen in 1900.

This sceptical Neovitalism is far surpassed by the dogmatic system, the chief actual representatives of which are the botanist Johannes Reinke and the metaphysician Hans Driesch. The vitalist writings of the latter, which are devoid of any grasp of historical development, have gained a certain vogue through the extraordinary arrogance of their author and the obscurity of his mystic and contradictory speculations. Reinke, on the other hand, has presented his transcendental dualism in clever and attractive form in two works which deserve notice on account of their consistent dualism. In the first of these, The World as Reality (1899), Reinke gives us "the outline of a scientific theory of the universe." The second work (1901) has the title, Introduction to Theoretical Biology. The two works have the same relation to each other as my Riddle of the Universe and the present supplementary volume. As our philosophic convictions are diametrically opposed in the main issues, and as we both think ourselves consistent in developing them, the comparison of them is not without interest in the great struggle of beliefs. Reinke is an avowed supporter of dualism, theism, and teleology. He reduces all the phenomena of life to a supernatural miracle.

Second Table

ANTITHESIS OF THE MONISTIC AND DUALISTIC THEORIES OF ORGANIC LIFE

Monistic Theory of Life
(Biophysics)		 Dualistic Theory of Life
(Vitalism)
1. The phenomena of life aremerely functions of plasm,determined by the physical,chemical, and morphologicalcharacter of theliving matter.1. The phenomena of life arewholly or partly independentof the plasm, anddetermined by a specialimmaterial force, the vitalforce (vis vitalis).
2. The energy of the plasm (asthe sum-total of the forceswhich are connected withthe living matter) is subjectto the general laws ofphysics and chemistry.2. The energy of the plasm iswholly or partly subjectto the immaterial vitalforce, which controls anddirects the physical andchemical forces of theliving matter.
3. The obvious regularity of thevital processes and theorganization they produceare the outcome of naturalevolution; their physiologicalfactors (heredityand adaptation) are subjectto the law of substance.3. The general regularity in theorganization and in thevital processes it accomplishesis the outcome ofconscious creation; it canonly be explained by intelligentimmaterial forceswhich are not subject tothe law of substance.
4. All the various functionshave thus been mechanicallyproduced, orderlystructures having beencreated by adaptation andtransmitted to posterityby heredity.4. All the various functions oforganisms have been producedby design, thehistorical evolution (orphyletic transformation)being directed to a preconceivedideal end.
5. Nutrition is a physico-chemicalprocess, the metabolismof which has ananalogy in inorganic catalysis.5. Nutrition is an inexplicablemiracle of life, and cannotbe understood by chemicaland physical processes.
6. Reproduction is a mechanicalconsequence of transgressivegrowth, analogousto the elective multiplicationof crystals.6. Reproduction is an inexplicablemiracle of life,without any analogy ininorganic nature.
7. The movement of organismsis, in every form, notessentially different fromthe movements of inorganicdynamos.7. The movement of organismsis an inexplicable metaphysicalmiracle of life,specifically different fromall inorganic movements.
8. Sensation is a general formof the energy of substance,not specifically differentin sensitive organisms andirritable inorganic objects(such as powder, dynamite).There is no suchthing as an immaterialsoul.8. The sensation of organismscan only be explained byascribing a soul to them,an immaterial, immortalbeing that only dwells fora time in the body. Afterdeath this spirit lives anindependent life.

III