same is true of molecules or mass-particles, which consist of two or more atoms.[1] But these elementary psychical activities which are attributed to the atoms are unconscious processes. Consciousness and soul-life are not identical terms; consciousness forms but a part of soulphenomena; the largest part of the latter is unconscious,[2] There is no immaterial substance; experience never reveals such a thing, no force that is not bound to matter, no form of energy that is not mediated by movements of matter.
There is no difference between organic and inorganic nature. All phenomena are explained by physico-chemical forces in each realm. The doctrine of the vitalists is absurd. The peculiar chemical-physical properties of carbon—particularly of the carbon compounds—are the mechanical causes of the peculiar movements which distinguish the organic from the inorganic world. Life, in other words, is the product of inorganic nature, the living plasm originated from inorganic carbon compounds,[3] The universe is a unity, all natural forces are one. All the phenomena of organic life are subject to the universal law of substance, as much so as inorganic phenomena.
The higher forms of life are developed from the lower in accordance with the principles of the theory of evolution as advanced by Darwin. That man is descended from the higher apes is now an absolutely proved fact. The idea of purpose, the teleological explanation, which was eliminated from physical science long ago, can not be accepted in biology. The theory of natural selection proposed by Darwin explains the origin of so-called purposive organisms by purely mechanical causes. There is no purposive impulse discoverable anywhere in organic life; everything is the necessary result of the struggle for existence, which acts as a blind regulator and not as a foreseeing God, and which causes the transformation of organic forms by the reciprocal action of the laws of heredity and adaptation. Nor is there any such purposiveness in our moral life or in history, individual or racial. Mechanical causality explains everything.
We turn now to Haeckel's philosophy of soul, to which he devotes one third of the entire space of the 'Weltraethsel.'[4] The soul is a natural phenomenon; hence psychology is a branch of natural science, particularly of physiology. The so-called psychologists are ignorant of anatomy and physiology, hence the largest part of psychological literature is to-day worthless waste paper. The prevalent conception of soul life regards soul and bod)' as two different beings, says Haeckel, and this view has nothing to stand on. Soul life is a sum total of vital
