“ For what does it matter to metaphysics whether by association sensations suggest ideas, and so give rise to ideas of substance and causation a posteriori, or synthetic unity of consciousness combines sensations by a priori notions of substance and causation into objects which are merely mental phenomena of experience, when it is at once allowed by the followers of Hume and Kant alike that reason in any logical use has no power of inferring things beyond the experience of the reasoner? ”

“ What kind of metaphysics, then, follows from this compound of psychology and epistemology? As with Kant against Hume, so with Wundt against Mach and Avenarius, the world we know will contain something more than mere complexes of sensations, more than pure experience: with Wundt it will be a world of real causes and some substances, constituted partly by experience and partly by logical thinking, or active inner will. But as with Kant, so with Wundt, this world will be only the richer, not the wider, for these notions of understanding ”

“ This exaggeration of the real fact of the will to think ignores throughout the position of little man in the great world and at the mercy of things which drive him perforce to sense and from sense to thought. It is a substitution of will for evidence as ground of assent, and a neglect of our consciousness that we often believe against our will (e.g. that we must die) , often without even an impulse to believe, often without taking any interest, or when taking interest in something else of no importance. ”

“ Science, says the materialist, proves that all known things are material phenomena. Yes, rejoins Lange, but Kant has proved that material are merely mental phenomena; so that the more the materialist proves his case the more surely he is playing into the hands of the idealist—an answer which would be complete if it did not turn on the equivocation of the word “phenomenon,” which in science means any positive fact, and not a mere appearance, much less a mental appearance, to sense and sensory experience. ”

“ By inference we know that things, such as the farther side of the moon, which neither are, nor have been, nor can be, present to an experiencing subject on the earth, nevertheless exist. But, on the hypothesis that knowledge contains no inferences beyond experience, it follows that all the objects of knowledge, being objects of experience, are, or have been, or can be, present to an experiencing subject. ”

“ To understand Wundt is to discover what a mess modern psychology has made to metaphysics. To understand phenomenal idealism in Germany is to discover what a narrow world is to be known from the transcendental idealism of Kant shorn of Kant’s inconsistencies. To understand noumenal idealism in Germany and the rise of metaphysical idealism in modern times is to discover that psychological is the origin of all metaphysical idealism. If we perceive only what is mental, all that we know is only mental. But who has proved that psychological starting-point? ”

“ Nor does he see that a man is conscious not of idea, feeling, will, experience, but of something conceiving, feeling, willing and experiencing, which he gradually learns to call himself, and that he is never conscious of doing all this “minding” without his body. If, then, these mental operations were merely actuality, they would be actuality of a man’s bodily substance. ”

“ It is not necessary for him to follow Schopenhauer, Hartmann and Fechner in endowing the material universe with will or any other mental operation, because his phenomenalism already reduces inorganic nature to mere objects of experiencing subjects. Wundt’s voluntarism takes a new departure, in which, however, he was anticipated by the paradox of Descartes: that will is required to give assent to anything perceived (Principia philosophiae, i. 34) . Wundt supposes not only that all organisms have outer will, the will to act, but also that all thinking is inner will the will to think. ”

“ He cannot allow any inference of things beyond ideas. His psychology poisons his logic.
In his logic, and especially in his epistemology, Wundt appears as a mediator between Hume and Kant, but with more leaning to the latter. While he regards association as lying at the basis of all knowledge, he does not think it sufficient, and objects to Hume that he does not account for necessity, nor for substance and causation as known in the sciences. He accepts on the whole the system of synthetic understanding which Kant superimposed on mere association. ”

“ The “empirio-criticism” of R. Avenarius (q.v.) is the hypothesis of the inseparability of subject and object, or, to use his own phraseology, of ego and environment, in purely empirical, or a posteriori form. It is like “immanent philosophy,” in opposing experience to the transcendent; but it also opposes experience to the transcendental, or a priori. Empirio-Criticism. It opposes “pure experience” to “pure reason,” while it agrees with Kant’s limitation of knowledge to experience. Avenarius held a view of knowledge very like that of Mach’s view of the economy of thinking. ”

“ Sensation, as Aristotle said, is not of itself: it is the apprehension of a sensible object in the organism. I perceive pressure, heat, colour, sound, flavour, odour, in my five senses. Having felt reciprocal pressures in touch, I infer similar pressures between myself and the external world. ”

“ On the other hand, as the speculative systems of noumenal idealism, starting from Fichte, succeeded one another, like ghosts who “come like shadows, so depart,” without producing conviction, and often in flagrant opposition to the truths of natural science, and when, in consequence, a wave of materialism threatened to submerge mind altogether by reducing it to a function of matter, many philosophers began to despair of the ambitious attempts which had been made to prove that there is a whole world of mind beyond phenomena, as the noumenalists had supposed. ”

“ In truth there is no sound answer to Materialism, except that, besides bodily substance, psychical substance is also necessary to explain how man performs mental actualities consciously (see case Physical Realism, ch. v.) . Wundt, however, has satisfied himself, like Fechner, that there is no real opposition of body and soul, and concludes, in accordance with his own phenomenalism, that his body is only an object abstracted from his unitary experience, which is all that really is of him. ”

“ But, using substance as he does always in the Kantian sense of permanent substratum beneath changing phenomena, and never in the Aristotelian sense of any distinct thing, he proceeds to make distinctions between the applications of causality and of substance. Even in the physical, he confines substance to matter, or what Aristotle would call material causes, thus makes its power to be merely passive, and limits substantial causality to potential energy, while he supposes that actual causality is a relation not of substances but of events. ”

“ No real advance in metaphysics can take place, and natural science itself is in some danger, until the true history of the evidences of the laws of mechanical force is restored; and then it will soon appear that in the force of collision what we know is not material points determining one another’s opposite accelerations, but bodies by force of impenetrable pressure causing one another to keep apart. ”

“ Wundt, starting from a psychology of unitary experience, deduces a consistent metaphysics of no inference of things transcending experience throughout—or rather until he came to the very last sentence of his System der Philosophie (1889) , where he suddenly passes from a necessity of “ideals” (Ideen) , to a necessity of “faith” (Glauben) , without “knowledge” (Wissen) . He forgets apparently that faith is a belief in things beyond ideas and ideals, which is impossible in his psychology of judgment and logic of inference. The fact is that his System may easily seem to prove more than it does. ”

“ Wundt accepts Fichte’s theory of the actuality, and Fechner’s synechological view, of the soul. Taking substance entirely in the sense of substrate, he argues that there is no evidence of a substantial substrate beneath mental operations; that there is nothing except unitary experience consisting of ideas, feelings, volitions, and their unity of will; and that soul in short is not substantia, but actus. He does not see that this unity is only apparent, for men think not always, and will not always. ”

“ If knowledge is experience of ideas distinguished by inner will of apperception into subject and object in inseparable connexion, if the starting-point is ideas, if judgment is analysis of an aggregate idea, if inference is a mediate reference of the members of an aggregate of ideas to one another, then, as Wundt says, all we can know, and all reason can logically infer from such data, is in our ideas, and consciousness without an object of idea is an abstraction ”

“ Thus they were thrown back on the limits of human knowledge prescribed by Kant, but purged of the unknown thing in itself by Fichte. Phenomenal idealism is the Kantian contention that Nature, as known to science, is phenomena of experience. ”

“ Apperception in general thus becomes activity of inner will, constituting the process of attention, passive in the form of impulsive will required for association, and active in the form of decisive will required for understanding and judgment. Now, beneath these confusing phrases the point to be regarded is that, in Wundt’s opinion, though we can receive sensations, we cannot think at all beyond sense, without some will. ”

“ He comes near to Hume’s substitution of succession of phenomena for real causality. He holds, like Hume, that nothing is real except our sensations and complexes of sensory elements; that the ego is not a definite, unalterable, sharply bounded unity, but its continuity alone is important; and that we know no real causes at all, much less real causes of our sensations; or, as he expresses it, bodies do not produce sensations, but complexes of sensations form bodies. ”

“ In a word, Mach and Kirchhoff agree that force is not a cause, convert Newtonian reciprocal action into mere interdependency, and, in old terminology, reduce mechanics from a natural philosophy of causes to a natural history of mere facts. ”

“ The conclusion that reason in transcending experience can show no more than the necessity of “ideals” is the only conclusion which could follow from Wundt’s phenomenalism in psychology, logic, and epistemology. ”

“ It is indeed difficult to assign any rational place to the empirio-criticism of Avenarius. It is materialistic without being materialism; it is realistic without being realism. Its rejection of the whole relation of physical and psychical makes it almost too indefinite to classify among philosophical systems. ”

“ On the assumption, then, that time and space are not objects, but systems, of sensations, he concludes that a body in time and space is “a relatively constant sum of touch-and-light-sensations, joined to the same time-and-space-sensations,” that each man’s own body is included in his sensations, and that to explain sensations by motions would only be to explain one set of sensations from another. In short, sensations are elements and bodies complexes of these elements. ”

“ His second position is his voluntarism. He agrees with Schopenhauer that will is the fundamental form of the spiritual. He does not mean that will is the only mental operation; for he recognizes idea derived from sensation, and feeling, as well as will. Moreover, he contends that we can neither have idea without feeling and will, nor will without idea and feeling; that idea alone wants activity, and will alone wants content; that will is ideating and activity (vorstellende Thätigkeit) , which always includes motives and ends and consequently ideas. ”

“ He considered that the whole hypothesis that an outer physical thing causes a change in one’s central nervous system, which again causes another change in one’s inner psychical system or soul, is a departure from the natural view of the universe, and is due to what he called “introjection,” or the hypothesis which encloses soul and its faculties in the body, and then, having created a false antithesis between outer and inner, gets into the difficulty of explaining how an outer physical stimulus can impart something into an inner psychical soul. ”

“ But the idealists are only too glad to get any excuse for denying bodily substances and causes; and, while Leibnitz supplied them with the fancied analysis of material into immaterial elements, and Hume with the reduction of bodies to assemblages of sensations, Mach adds the additional argument that bodily forces are not causes at all. In Great Britain Mach’s scepticism was welcomed by Karl Pearson to support an idealistic phenomenalism derived from Hume, and by Ward to support a noumenal idealism derived from Lotze. ”

“ Sir Christopher Wren made many experiments before the Royal Society, which were afterwards repeated in a corrected form by Sir Isaac Newton in the Principia, experimentally proving that bodies of ascertained comparative weights, when suspended and impelled against one another, forced one another back by impressing on one another opposite changes of velocity inversely as their weights and therefore masses; that is, by impressing on one another equal and opposite changes of momentum. ”

“ He agrees with Fechner that physical process of nerve and psychical process of mind are really the same psychophysical process as appearing on the one hand to an observer and on the other hand to one’s own consciousness; and that physical phenomena only produce physical phenomena, so that those materialists and realists are wrong who say that physical stimuli produce sensations. ”

“ What, then, is this pure experience? “Every human individual,” says he, “originally accepts over against him an environment with manifold parts, other individuals making manifold statements, and what is stated in some way dependent upon the environment.” Statements dependent upon the environment are what he means by pure experience. At first this starting-point looks like dualistic realism, but in reality the author only meant dualism within experience. ”

“ But whereas Fechner and Paulsen hold that all physical processes are universally accompanied by psychical processes which are the real causes of psychical sensations, Riehl rejects this paradox of universal parallelism in order to fall into the equally paradoxical hypothesis that something or other, which is neither physical not psychical, causes both the physical phenomena of matter moving in space and the psychical phenomena of mind to arise in us as its common effects. ”

“ When Fichte had rejected the Kantian soul in itself and developed the Kantian activity of apperception, he considered that soul consists in constructive activity. Fechner added that the soul is the whole unitary spiritual process manifested in the whole unitary bodily process without being a substance. ”