§ 2. The Science of the Soul
As a distinct science, psychology owes its origin to Aristotle, whose “Peri Psyches” is, in all probability, the first formal treatise on the subject. Through his father, Nichomachus, who was court physician to Philip of Macedon, he became acquainted, at an early age, with biological lore in the form of such medical botany, anatomy, and physiology as were commonly known in prescientific days. Subsequently, his celebrated pupil, Alexander the Great, placed at his disposal a vast library, together with extensive opportunities for biological research. This enabled the philosopher to criticize and summarize the observations and speculations of his predecessors in the field, and to improve upon them by means of personal reflection and research. In writing his psychology, he was naturally forced to proceed on the basis of the facts discoverable by internal experience (introspection) and unaided external observation. Of such facts as are only accessible by means of instrumentation and systematic experimentation, he could, of course, know nothing, since their exploration awaited the advent of modern mechanical and optical inventions. But the factual foundation of his treatise, though not extensive, was solid, so far as it went, and his selection, analysis, and evaluation of the materials at hand was so accurate and judicious, that the broad outlines of his system have been vindicated by the test of time, and all the results of modern experimental research fit, with surprising facility, into the framework of his generalizations, revision being nowhere necessary save in nonessentials and minor details. Wilhelm Wundt, the Father of Experimental Psychology, pays him the following tribute: “The results of my labors do not square with the materialistic hypothesis, nor do they with the dualism of Plato or Descartes. It is only the animism of Aristotle which, by combining psychology with biology, results as a plausible metaphysical conclusion from Experimental Psychology.” (“Grundzüge der physiologischen Psychologie,” 4te Auflage, II, C. 23, S. 633.)
Literally translated, the title of Aristotle’s work signifies a treatise concerning the soul. It set a precedent for the scholastic doctors of the thirteenth century, and de anima became with them a technical designation for all works dealing with this theme. In the sixteenth century the selfsame usage was embalmed in the Greek term psychology, which was coined with a view to rendering the elliptic Latin title by means of a single word. Melanchthon is credited with having originated the term, which, in its original use as well as its etymology, denoted a science of the psyche or soul.
Towards the close of the seventeenth century, however, the meaning of the term in question began to undergo a marvelous evolution, of which the end is not yet. The process was initiated by Descartes, under whose auspices psychology was changed from a science of the soul into a science of the mind. Then, under the influence of Hume and Kant, the noumenal mind disappeared, leaving only phenomenal consciousness. Recently, with the advent of Watson, even consciousness itself has been discarded and psychology has become a science of behavior. And here, for the time being, at any rate, the process has come to a stop, just one step short of complete nihilism. Woodworth quotes the following waggish comment: “First psychology lost its soul, then it lost its mind, then it lost consciousness; it still has behavior of a kind.” (“Psychology, the Science of Mental Life,” p. 2, footnote.) This gradual degeneration of psychology from animism into behaviorism is one of the greatest ironies in the history of human thought. All of this, however, was latent in the corrosive Cartesian principle of “scientific doubt.” Facilis descensus Averni! It is easy to question the validity of this or that kind of human knowledge, but difficult to arrest, or even foresee, the consequences which the remorseless logic of scepticism portends.
Disintegration set in, as has been said, when Descartes substituted his psychophysical dualism of mind and matter for Aristotle’s hylomorphic dualism of soul and body. The French philosopher, in an appendix to his “Meditations,” which dates from 1670, expressly rejects the Aristotelian term of soul or psyche, and announces his preference for mind or spirit, in the following words: “The substance in which thought immediately resides is here called mind (mens, esprit). I here speak, however, of mens (mind) rather than anima (soul), for the latter is equivocal, being frequently applied to denote what is material” (“Reply to the Second Objections,” p. 86). Henceforth psychology ceased to be a science of the soul, and became, instead, a science of the mind.
Descartes, one must bear in mind, divided the universe into two great realms of being, namely: the conscious and the unconscious, the psychic world of mind and the physical world of matter, unextended substance which thinks and extended substance which moves. In man these two substantial principles were conceived as being united by the tenuous link of mere contact, the spirit or mind remaining separate from, and unmingled with, its material partner, the body. The main trouble with this dualism is that it draws the line of demarcation at the wrong place. Reason and sense-consciousness are bracketed together above the line as being equally spiritual; physiological processes and processes purely physicochemical are coupled below the line as being equally mechanical. Now, when a brain-function such as sense-perception is introduced, like another Trojan Horse, into the citadel of spiritualism, it is a comparatively easy task for materialism to storm and sack that citadel by demonstrating with a thousand neuro-physiological facts that all sensory functions are rigidly correlated with neurological processes, that they are, in short, functions of the nervous system, and therefore purely material in nature. On the other hand, once we retreat from the trench of distinction between the processes of unconscious or vegetative life and the physicochemical processes of the inorganic world, that moment we have lost the strategic position in the conflict with mechanism, and nothing avails to stay its triumphant onrush. Hence, from first to last, it is perfectly clear that the treacherous psychophysical dualism of Descartes has done far more harm to the cause of spiritualism than all the assaults of materialism. There is a Latin maxim which says: Extrema sese tangunt—“Extremes come in contact with each other.” The ultraspiritualism of Descartes by confounding spiritual, with organic consciousness, leads by the most direct route to the opposite extreme of crass materialism.
Aristotle’s dualism of matter and form, which is but a physical application of his transcendental dualism of potency (dynamis) and act (entelechy), is very different from the Cartesian dualism of the physical and the psychic. According to the Aristotelian view, as we have seen in the last chapter, all the physical entities or substantial units of nature (both living and inorganic) are fundamentally dual in their essence, each consisting of a definitive principle called entelechy and a plastic principle called matter. Entelechy is the integrating determinant, the source of the unit’s coherence and of its differentiation from units of another type. Matter is the determinable and quantifying factor, in virtue of which the unit is potentially-multiple and endowed with mass. In the electro-chemical reactions of non-living substances (synthesis, analysis, and transmutation), entelechy is the variant and matter is the constant; in the metabolic activities of living substances (assimilation and dissimilation), matter is the variant and entelechy is the constant. This persistent entelechy of the living unit or organism is what Aristotle terms the psyche or soul. The latter, therefore, may be defined as the vital principle or primary source of life in the organism.
But in using such terms as “soul” and “vital principle” we are employing expressions against which not merely rabid mechanists, but many conservative biologists as well, see fit to protest. The opposition of the latter, however, is found on closer scrutiny to be nominal rather than real. It is the name which offends; they have no objection to the thing signified. Wilson, to cite a pertinent example, rejects as meaningless all such terms as “vital principle,” “soul,” etc. “They are words,” he avers, “that have been written into certain spaces that are otherwise blank in our record of knowledge, and as far as I can see no more than this.” (“Biology,” p. 23, 1908.) Yet he himself affirms again and again the existence of the reality which these terms (understood in their Aristotelian sense) denote. In discussing the relation of the tissue cell to the multicellular body, for instance, he speaks of “a formative power pervading the growing mass as a whole.” (“The Cell,” 2nd ed., p. 59), and, in his recent lecture on the “Physical Basis of Life,” he makes allusion to “the integrating and unifying principle in the vital processes.” (Science, March 9, 1923, p. 284.) It would seem, therefore, that Wilson’s aversion to such terms as soul and vital principle is based on the dynamic sense assigned to them by the neo-vitalists, who, as we have seen, regard the vital principle as a force sui generis or a unique agent, which operates intrusively among physicochemical factors in the rôle of an active or efficient cause of vital functions. That such is really the case, appears from his rhetorical question: “Shall we then join hands with the neo-vitalists in referring the unifying and regulatory principle to the operation of an unknown power, a directive force, an archæus, an entelechy or a soul?” (Loc. cit., p. 285—italics mine.) The objection, however, does not apply to these terms used in their Aristotelian sense. In the philosophy of the Stagirite, the soul, like all other entelechies, is a cause in the entitive, but not in the dynamic, order of things. Its efficacy is formal, not efficient. It is not an agent, but a specifying type. The organism must be integrated, specified, and existent before it can operate, and hence its integration and specification by the soul is prior to all vital activity. The soul is a constituent of being and not an immediate principle of action. The soul is not even an entity (in the sense of a complete and separate being), but rather an incomplete entity or constituent of an entity. It takes a complete entity to be an agent, and the soul or vital entelechy is not an independent existent, which is somehow inserted into the organism, but an incomplete being which has no existence of its own, but only coexistence, in the composite that it forms with the organism. Nor is there any such thing as a special vital force resident in the organism. The executive factors in all vital operations of the organic order are the physicochemical energies, which are native to matter in general. These forces, as we have seen, receive a reflexive orientation and are elevated to a higher plane of efficiency by reason of their association with an entelechy superior to the binding and type-determining principles present in inorganic units, but they are not supplanted or superseded by a new executive force. Wilson’s fear, therefore, that the experimental analysis of life is discouraged by vitalism, inasmuch as this conception subtracts something from the efficiency of the physicochemical forces, is groundless in the case of hylomorphic vitalism, but is well-founded in the case of such systems as the neo-vitalism of Driesch and the spiritualism of Descartes.
Summing up, therefore, we may say that the soul, like other entelechies, is consubstantial with its material substrate, the body. True it is more autonomous than are the inflexible entelechies of inorganic nature, inasmuch as it is independent of any given atom, molecule, or cell in the organic aggregate. Such a degree of freedom, for example, is not possessed by the most complex molecules, which show no other flexibility than tautomerism, even this small readjustment involving a change in their specificity. But this autonomy does not preclude the essential dependence of the soul upon the body. Generally speaking, the soul is incapable of existence apart from its total substrate, the organism. We say, generally speaking, because, as previously intimated, an exception must be made in the case of the human soul, which, being, as we shall see, a self-subsistent and spiritual entelechy, is by itself, apart from its material substrate, a sufficient subject of existence, and is therefore capable of surviving the dissolution of its complementary principle, the organism. Nevertheless, even in man, the soul forms one substance with the organism, and the organism participates as a coëfficient factor in all his vital functions, both physiological and psychic, excluding only the superorganic or spiritual functions of rational thought and volition, whose agent and recipient is the soul alone. In man, then, soul and body unite to form a single substance, a single nature, and a single person. Apart from the body, the human soul is, indeed, a complete entity, in the sense that it is capable of subsistence (independent existence), but, in another sense, it is not a complete entity, because apart from the body it cannot constitute a complete nature or complete personality. It is this essential incompleteness of the discarnate human soul that forms the natural basis of the Christian doctrine of the Resurrection of the Dead.
Here, however, it is important to note the difference between the hylomorphic spiritualism of Aristotle and the psychophysical spiritualism of Descartes. By the latter all conscious or physic functions are regarded as spiritual. The former, however, recognizes the fundamental difference which exists between the lower or animal, and the higher or rational functions of our conscious life. Sense-perception and sensual emotion belong to the former class, and must be regarded as organic functions, whose agent and subject is neither the soul alone nor the organism alone, but the soul-informed organism or substantial composite of body and soul. Rational thinking and willing, on the contrary, are classified as superorganic or spiritual functions, inasmuch as they exclude the coägency of the organism and have the soul alone for their active cause and receptive subject.
The soul, in fine, is the formal principle or primary source of the threefold life in man, namely, the metabolic life, which man shares with plants, the sentient life, which he shares with animals, and the rational life, which is uniquely human. The human soul is often spoken of as the mind. In their dictionary sense, both terms denote one and the same reality, namely, the human entelechy or vital principle in man, but the connotation of these terms is different. The term soul signifies the vital principle in so far as it is the primary source of every kind of life in man, that is, vegetative, sentient, and rational. The term mind, however, connoting conscious rather than unconscious life, signifies the vital principle in so far as it is the root and ground of our conscious life (both sentient and rational). Here, however, the distinction is of no great moment, and the terms may be regarded as synonymous. The definitions which we have given are, of course, blasphemous in the ears of our modern neo-Kantian phenomenalists, whose preference is for a functional, rather than a substantial, mind or soul; but we will pay our respects to them later.
It is clear, however, from what has been said, that, for evidences of the superiority and spirituality of the human soul, we must recur, not to the external manifestations of our nutritive life, but to the internal manifestations of our conscious life. The latter are wholly inaccessible to the external senses and perceptible only to the intuition of consciousness, introspection, or internal experience, as it is variously called. All our self-knowledge rests on the basis of introspection, and without it the science of psychology would be impossible. In fact, not only psychology, but the physical sciences as well, depend for their validity on the testimony of consciousness; for the external world is only knowable to the extent that it enters the domain of our consciousness. Recently, as we have seen, a tendency to discredit internal experience has arisen among materialistic extremists. This “tendency,” to quote the words of Keyser, “most notably represented by the behaviorist school of psychologists (like Professor Watson, for example), is manifest in the distrust of introspections as a means of knowledge of mental phenomena and in the growing dependence of psychology upon external observation of animal and human behavior and upon physiological experiment, as if matter were regarded ‘as something much more solid and indubitable than mind’ (Bertrand Russell).”—C. J. Keyser, Science, Nov. 25, 1921, p. 520. Since, however, all our knowledge depends on the validity of consciousness, such a tendency is suicidal and destructive of all science, whether physical or psychological. The attempts, therefore, of mechanists, like Loeb, and behaviorists, like Watson, to dispense with consciousness overreach themselves. For how can the mechanists know that there are such things as tropisms, tactisms, or reaction-systems, how can the behaviorist study such things as “situations,” “adjustments,” and S-R-bonds, how can the materialist become aware of the existence of molecules and atoms, except through the medium of their own conscious or psychic states? States of matter can be known only by means of states of mind, and the former, therefore, cannot be any more real than the latter. “What, after all,” asks Cardinal Mercier, “is a fact of nature if the mind has not seized, examined, and assimilated it? True, the information of consciousness is often precarious. For this reason we do well to aid and control it by scientific apparatus. These apparatus, however, can only aid, never supplant, introspection. The telescope does not replace the eye, but extends its vision.” (“Relation of Exp. Psych. to Philosophy,” pp. 40, 41—Trans. of Wirth.)