A more formidable apprehension is the one that there will slip in, under the name of physiological psychology, not a science, but a doctrine, and this—to call things by their right names—the materialistic doctrine. This objection should be examined to the bottom; it is important to have it removed, not only in the interests of sound thought, but also in those of the science which is concerned. Nothing could be more fatal to the future of this science than to give it a materialistic significance.
In principle, psycho-physiological science is neither materialistic nor spiritualistic. It is, or ought to be, exclusively experimental and scientific. Its disinterested character in this respect is proved by the fact, which has not been sufficiently insisted on, that it was founded by men of spiritual belief: the spiritualist Descartes; after him the mystic Malebranche; and, succeeding them, Charles Bonnet, of Geneva, the most religious man of the eighteenth century. Among contemporary German psychologists, as named by M. Ribot, are Lotze, an avowed believer in spirit, who has revived Leibnitzianism in Germany; Helmholtz, the great physicist, is a Kantian, as also is Wundt, the chief of the school, who declares that physiology can account for the inferior but not for the superior faculties of the human mind; Fechner, the discoverer of the law that bears his name, is an illuminate far more spiritual than materialistic; and Weber is a pure physicist, indifferent as between metaphysical schools. Thus, not one of the most authoritative masters of the new science in Germany is a materialist. The same can not be said of all the physiologists who are occupied with these questions; but the science itself is indifferent as between the two doctrines, and can associate itself with either. Yet, to be just, and not to hold to appearances only, it is clear that a science which occupies itself with the physiological conditions of thought, or with the part played by matter in the operations of the mind, will always have a color of materialism. If Descartes had only written the first part of the "Treatise on the Passions," in what could this treatise be distinguished from Lamettrie's "Homme-Machine"? Suppose, now, that in consequence of the multiplication of objects of study, and through the division of labor, an author should limit his studies to the first order of researches, without adding the corrective, as Descartes did in the third part of the "Passions," should that make him pass as a materialist? Certainly not. All that we can ask of him is to leave such questions open.
A second right that can not be denied to psycho-physiology is that of establishing and affirming facts, whether or not they be agreeable to this or that doctrine. For example, the fact of hypnotic suggestion recently brought to light has a frightful appearance to many minds, who believe that it involves the overthrow of
