Popular Science Monthly/Volume 25/June 1884/Physiology versus Metaphysics


"The laboratory is the forecourt of the temple of Philosophy; and whoso has not offered sacrifices and undergone purification there, has little chance of admission into the sanctuary."—Huxley, "Life of Hume."

"It was the glory of Hippocrates to have brought Philosophy into Medicine, and Medicine into Philosophy."—Auctor (?).

"Attendre et espérer" (To wait and hope).—Dumas, "Monte Cristo."

FEW physiologists, mixing in general society, can have failed to notice how common it is to hear their psychological brethren (if referred to at all) stigmatized as atheists; and this alike in coteries distinguished for pugnacious religious dogmatism, and in social circles where indifferentism marks the prevailing tone of thought. The acrimony with which the charge is made apparently increases, on the one hand, in the direct ratio of the bigotry or religious fervor, and, on the other, in the inverse ratio of the scientific enlightenment of different speakers. Furthermore, in certain cliques a shrewd suspicion seems to have arisen that, as any whole includes its parts, physiology in general (nay, even medical science at large) is chargeable with the delinquencies of its cerebral department, and is hence condemned by these judges as a representative in its entirety of atheistic proclivity and purpose. An illustration in point may be found in the columns of the leading daily journal, wherein the reviewer of the volumes of Bain, Bastian, and Luys on Mind, Body, and Brain, "need scarcely say that in all three works the physiological (some would say materialistic) aspects of the subject are strongly insisted upon."[1] No doubt some would say so, and thence at a bound jump to the conclusion (a foregone one with all who use the word "materialist" in an adverse sense) that all these authors are "atheists." In point of fact, the masses are hardly wiser in their estimate of medical belief than two centuries ago, when lay smartness and ignorance combined had fashioned the libelous apothegm, "Ubi tres medici, ibi duo athei"[2](where three doctors are, there are two atheists).

Now, metaphysical psychologists, though inquiring as boldly from their point of view into the genesis of mind, have contrariwise, with rarest exceptions, escaped and continued to escape this form of social obloquy. Whence comes this diversity of judgment? Are physiologists thus penalized because they have shown that a certain definite, if subordinate, part is played by physics and chemistry in the complex act of evolving thought, and because they have thus, at least partially, succeeded in wrenching this branch of philosophy from the nerveless grasp of the pure introspectionist? Has the success of cerebral physiology in the surface-penetration of some of the secrets of thought-production led to its condemnation? Should those secrets, in obedience to theological casuistry, be allowed to linger on in primitive obscurity, as though the earnest use of our divinest gift, intellect, were not the most fitting and the most grateful form of homage to the all-bounteous Giver? If our science toils on in humble but trusting hope to fathom on material lines the mechanism of our mental operations, is its pursuit antagonistic to belief in an Almighty First Cause?[3] Is there really any fair ground for the inference, that because physiology strives to trace out and interpret the conditions of the connection between brain-substance and mind—ergo, those who labor in its field are of necessity atheists? The inquiries seem to deserve an answer. Let us, then, see to what the teachings of physiology in this direction really amount. Let us try to determine whether (conflicting though they may prove with the postulates of various narrow and sectarian systems of theology) those teachings really antagonize any formal or essential principle of deistic faith, whether, though confessedly open to the charge of "heresy" (that charge so dear to sacerdotalism),[4] they do not escape even the suspicion of that treason against nature, atheism?[5]

We must prelude the inquiry into the direct work of physiology by a very rapid glance at the notions advanced by metaphysicians and theologians on the nature of mind and generation of thought. Our task throughout will be merely one of historical and very occasionally critical review. We lay no claim to originality of doctrine, but shall merely attempt in simple fashion to popularize knowledge, which, alike from its nature and from the manner of its handling, has been essentially limited to the few.

1. Now, metaphysicians (they who profess their ability to formulate an a priori theory of the ultimate elements of knowledge and nature of things) have held, as a class, that the act of thinking is in all its stages and all its factors a non-material process. And it does not involve any serious error to maintain that the formula under which this doctrine obtained the widest acceptance by philosophy, while it best satisfied the craving of ordinary people for some insight into the nature of their mental operations, originated with Descartes. And this philosopher's well-known formula assumed: there exists a spiritual, non-extended, indivisible substance, an objective, immortal entity, superadded to and independent of brain, which thinks, feels, and wills—a substance cognizable by self-consciousness alone, and which is in fact the "thinking principle" or proper "soul." Mind thus becomes absolutely and wholly an extra-cerebral product, and the possible offspring of activity on the part of the "soul" alone. The purely hypothetical character of this doctrine, the feeble, in some sense half-hearted, support given it by its originator, its incompatibility with every-day experiences of cerebral disease, and its proving a hopeless puzzle to cultured people, at once endowed with the critical faculty and unbiased by prejudice, all alike failed to shake its supremacy, and for long years it held sway, not as a makeshift, provisional, mere scholastic formula, but as an established primary truth. And all this, though Descartes himself, in the following words, honestly avowed his disbelief in the surety of his own doctrine: "Je confesse," he writes, "que par la seule raison naturelle nous pouvons faire beaucoup de conjectures sur l'âme et avoir de flatteuses espérances, mais non pas aucune assurance"[6] (I confess that by natural reason we can make many conjectures about the soul, and have flattering hopes, but no assurance).

Meanwhile, as mind was thus made a product of the soul, the question at once arose by necessary involution. What in turn was the soul? Now, in all probability, no more startling chapter figures in the history of philosophy than that chronicling the varied efforts made at furnishing a sufficing reply to this query. From the days of Plato to our own, metaphysicians seem to have lost themselves in a maze of conjectures, too often, unfortunately, no less dogmatic in tone than vague and unsatisfactory in essence. Yet be their failures, while unflinchingly registered, freely forgiven; the obscurity of the problem to be solved, coupled with the imperfection of the instrument selected for its solution, has ever proved an obstacle to success, even when that instrument has been handled by the deepest thinkers and most devoted searchers after truth.

Thus, setting aside the profanum vulgus of illogical and inaccurate writers, with whom the word is but a word, carrying with it no inkling even of definite signification, we find that with some philosophers the soul is a local, with others a universal, existence; by some limited to man, by others conceded to the lower animals; with certain thinkers an essence, with others a substance, with a third group a principle; with some an immaterial essence without form or extension, with others immaterial, yet possessed of these attributes of matter; with the majority a simple, with the minority a compound, existence, and with a small fraction of the latter a tripartite body, of which each division is again subdivided into three; with this sect a something contained in the body, with that a something containing it; with Aristotle an equivalent of "all the functions, sentient and nutritive, of living bodies up to the highest attributes of intellect," the "rational soul" being especially seated in the heart;[7] with the Neo-Platonists an "image or product of reason," producing in turn the corporeal; with Descartes the "spiritual substance," or "principle" just referred to, provided with a habitat in the pineal gland, a home exchanged by others for the ventricles, the corpora striata, the white substance of the hemispheres, their cortex, the plexus choroides, the dura mater, the heart, and the blood; with Locke a spiritual essence or a material substance—he could not "fixedly determine" which; with certain philosophers a something pre-existent from all time, with others evolved pari passu with the organism it inhabits; in the opinion of one group of school-men perishing with the associated body, in that of a second wholly immortal, in that of a third mortal in the main, but in one of its parts immortal. Further, philosophers who maintained each soul was formed specially for its own individual organism, varied in all conceivable ways as to the time and place of union of the two, while the parallel difficulty followed in settling the precise moment of somatic death at which separation of the two must occur.[8]

The vast majority of these speculators recoiled from the presumptuous task of attempting to define the actual composition of the soul, a few only of the most wildly transcendental satisfying themselves that it consisted of "a drop of ether," of a "globule or spark of heat or light," of an "animated vapor," etc.

Not more widely divergent than the metaphysical notions of the nature of soul were the doctrines held as to the manner of intercourse between the soul and the body, the school of Aristotle holding that all objects enter into the soul by influx through the senses; the Cartesians, per contra, maintaining that it is the soul that sees and hears, that perception is a primary faculty, not of an organ, but of the soul; while Leibnitz and his followers, denying alike the imagined influx from the body into the soul, and from the soul into the body, maintain the existence of a joint consent and coeval operation of both under the influence of a so-called pre-established harmony.

Passing from the earlier metaphysical speculators to Kant (1724–1804), we find once more in the history of human struggles after truth how much easier it is to destroy than to construct. In the firm analytical grasp of that extraordinary thinker ("the most tremendous disintegrating force of modern times") the past fallacies concerning the nature of the soul had scant chance of mercy—the past short-comings as little of escaping exposure. Ancient philosophic creeds crumbled to dust before him. But did he raise any edifice of practical significance on their ruins? Did he identify the soul? Where are they who can fancy that they are the wiser—that they have made a nearer approach to such identification—by accepting his quasi-mystic reveries on the "ego which exists beneath or rather outside consciousness,…a noumenon,[9] an indescribable something, safely located out of space and time, as such not subject to the mutabilities of these phenomenal spheres,…and of whos eontologic existence we are made aware by its phenomenal projections or effects in consciousness."[10] The first clauses of this definition seem pure assumption, soaring aloft beyond the comprehension of ordinary mortals; the latter (granting the premises of the so-called "noumenon") seems a mystified version of a necessary inference. Even Kant himself admits the total concept to be incapable of scientific proof; and of any other form of alleged proof—the so-called transcendental—what is the practical weight? Such "proof," inasmuch as it transcends experience, can never advance beyond the unreality of subjective formulation, can never attain the reality appertaining to objective demonstration. Nay, Kant admits more than this: he grants nothing can really be proved by metaphysics concerning the attributes, or even the existence, of the soul; while holding that, inasmuch as its reality can not, on the other hand, be disproved, such reality may, for moral purposes, be assumed. So that this sublimest of the world's thinkers is obliged in ultimate analysis to admit that ordinary common-sense may prove as successful in wrestling with the problem as the vastest inborn intellectual potentiality intensified by prolonged culture.

Reaching next the modified or hybrid metaphysical and physiological school of the present day (the former element largely predominant), we find one of its most eminent representatives. Bain, seeming to teach that, whatever it is, the soul has but loose connection with the body. "The body might," he assures us, "have its bodily functions without the soul, and the soul might have its psychical functions in some other connection than our present bodies.[11] But surely, as indeed this psychologist elsewhere himself admits, mind is a function of the body; therefore it follows implicitly from his propositions that mind may exist without the soul, whereas the metaphysical contention denies the possibility of thought without it. Note further that this thinker, with wise discretion, shrinks from any disclosure of his own idea, either by affirmation or negation, of the nature of the soul, and leaves us in total ignorance of what he desires us to understand, when on his own behalf he employs the word.

We may remark in passing, that Plato thought the soul could exist without a habitat in the human body. Kant, on the other hand, held it to be beyond our powers to make any affirmation as to the possibility of its separate existence. Dugald Stewart, somewhat in the same vein, held that we "have no direct evidence of the possibility of the thinking and sentient principle exercising its various powers in a separate state from the body." Here, be it observed, the soul, as with Descartes, is a "principle." Is this anything more than a mere word? What is the actual meaning of the term in this connection? or has it any meaning? What explanation does it furnish of the facts?

The foregoing brief analysis of metaphysical opinion, though obviously and necessarily imperfect, is not one-sided or dishonest, and seems to render the conclusion inevitable that introspective psychology has failed to supply a definite presentment of the nature of soul. Metaphysicians have, in truth, merely postulated its existence and endowed their creation with a series of attributes, the nexus of no single one of which with its assumed factor has ever been made the subject of serious proof; while, in speaking of mind as one manifestation of its activity, they simply ascribe the performance of a positive act (that of thinking), the mechanism of which they in no wise understand, to an agent (the soul), the mere existence of which they fail to substantiate.

If it be urged on behalf of any class of metaphysical school-men, who may refuse to accept Kant's modest avowal of failure, that they really have succeeded (because to their own contentment) in fathoming the problems of the genesis of mind and the nature of the soul, and that they are not answerable for the defective intelligence of the outside world, which fails to follow them, the physiologist need not hesitate to concede that they soar in a region of visionary transcendentalism, for which his mental bias and material modes of thought have not fitted him either as a worker or a critic. He is as ill adapted for reveling in trains of speculative abstraction, whereof the issue, purely subjective, can never reach the reality of objective demonstrativeness, as the metaphysician for peering through lenses many a weary day and night to verify a single fact, the present obvious value of which may be nil, but of which the future story may be written as the starting link of chains of important truths. Between the metaphysical contemplative mind and the scientific observant mind the antagonism is so profound that the union of the two qualities in the same individual, even in very different degrees of potentiality, is the rarest of intellectual endowments.

The physiologist of the pure observation school may, then, admit his deficiency in critical training for the just estimation of metaphysical methods, and this all the more resignedly in that (as we shall by-and-by fully see) metaphysicians are found occasionally confessing, nay boasting, that they fail to understand each other, while they are likewise accused, apparently on justifiable grounds, of not at all times and seasons thoroughly comprehending each man his own individual work. So the physiologist need not trouble himself about methods but ask for results. And this he has ventured to do, conceiving himself entitled by the worth of the latter to gauge the efficiency of the former. While, then, acknowledging in a spirit of homage savoring of of awe the abstract grandeur of the metaphysical intellect and the aims of its activity, he has earnestly but not irreverently inquired. Do you metaphysicians not deceive yourselves? Are you quite sure you do not take words for ideas? Have you or have you not perpetually confounded figments of the brain with realities? To what increments of true knowledge—the real, substantial knowledge of things—can you lay claim? Have you of late done much more than clothe old thoughts in new phraseology—phraseology of greater precision than that it has supplanted, we may fairly concede? Have you not in sober truth been engaged since the dawn of philosophy—multum agendi, pauxillum agentes (doing much, accomplishing little)—in a still beginning, never ending, logomachia? Can you point among your fellows to that emphatic unanimity of creed on fundamental questions which shall demand, as its right, acceptance from the outside world, before which you pose as the fountain-heads of all ultimate knowledge? Or, have you not, on the very contrary, disagreed absolutely with each other? And, if you doubt each other, may we not in turn doubt you all? Is it not true that Kant never mastered, and loudly proclaimed he never could master, the doctrine of Spinoza?[12] Did not the philosopher of Königsberg declare the system of Fichte to be utterly untenable? Does not Schopenhauer in turn repudiate Kant? Were not the leading principles of Schopenhauer's own system contained, and in some measure worked out, in Fichte's "Wissenschaftslehre"? And did not the same Schopenhauer, having failed to perceive the similarity (carping critics have been found malicious enough to more than hint that perhaps he herein judged wisely), stigmatize that work, the alleged germ of his own, as a "farrago of absurdities"?[13] Has not J. S. Mill declared it to be characteristic of Hamilton that he seldom or never adhered to any philosophic statement he had adopted, that "an almost incredible multitude of inconsistencies show themselves on comparing different passages of his works with each other," and that his whole system of "intuitional" philosophy is a profound mistake?[14] And is it not equally true that the adherents of the Scotch philosopher seem to have made it plain that his somewhat ruthless English critic never succeeded in understanding him?[15] Furthermore, has it not been averred by one of his most earnest panegyrists that Kant failed himself to grasp the full import of his own doctrines, that the "new light that was lighted for men" could not illumine his own ideas sufficiently to grasp their total meaning and anticipate the terms of their ultimate evolution?[16] Finally, has not Berkeley with equal truth and candor pronounced the condemnation alike of his own work and of all his fellow-craftsmen in the fatal admission, "We metaphysicians have first raised a dust, and then complain we can not see"?[17]

To the non-metaphysical mind it would indeed appear that the bootless speculations of the pure transcendentalist were calculated on the one hand to dishearten wayfarers on the road to truth by blocking the route with unintelligible mysticism, and on the other to postpone the discovery of a share of ligature's secrets by diverting any available mental power into a wrong channel.[18] How could aught but failure in solving the problems of mental philosophy be expected from a system, even though that system were sustained by surpassing intellectual force, that ignored the instrument, brain, by which the result, mind, is evolved? What success could be expected from an inquiry into the mechanism of respiration, from which all consideration of the structure, dynamics, and chemistry of the breathing-organs was purposely excluded? Conceive a man proceeding to investigate the respiratory process who had never seen a lung! Should we consider him perfectly sane? How ineffably curious, then, if not ludicrous, does it seem to find Bain announcing, with in some sort the tone of a man who has stumbled on a happy discovery, that it would be worth the while of metaphysicians to learn something of nerves—we presume, impliedly, something of brain also! Still this niggard dole of acknowledgment places the donor at all events in advance of J. S. Mill, who to the very close of his career contemptuously and obtrusively rejected cerebral physiology as a guide, of even the most subordinate value, in the study of mind. Why, the solitary discovery of the connection of aphasia with a special spot in a special gyrus of a special hemisphere of the brain, taken in conjunction with the corollaries logically deducible from that connection, seems a far weightier offering toward the elucidation of the actual mechanism of mind—of the conditions under which Nature works—than all the transcendental guesswork furnished by the toil of metaphysicians from Plato to Schopenhauer.

Nevertheless, the conspicuous failure of purely introspective philosophy, unaided by objective investigation, to establish its special psychic doctrines, does not, on the other hand, disprove the possible independent existence of soul as one of the factors of mind. Such existence may be, or may not be, a reality, for anything that metaphysics show or do not show. The failure of transcendentalism, admitted even by Kant, simply proves that in wisdom which is not of pure and unaided metaphysics lies such lingering hope, as an enthusiast may cling to, of substantiating the reality and the nature of the soul's existence and practical activity. Nor does the failure signify (whatever may be its import as to the efficiency of transcendentalism) that introspection must not be allowed to play a large though far from the solitary part in the attempt to elucidate the nature of mental operations. To reject the help of introspection in analyzing the phenomena of mind would be as illogical, nay fatuous, on the part of the physiologist as the negation of the utility of all objective aid by the bulk of metaphysicians. But in point of fact such rejection is a sheer impossibility, for we can not cogitate without examining consciousness, and when we do this we introspect. Besides, there are facts of mental operation, and laws regulating these facts, which lie without the pale of physiology as an objective factor, facts and laws which can only be even guessed at by the analysis of self -consciousness. The results of such analysis plainly can not be claimed by a department of inquiry which deals with phenomena physically demonstrable alone; be those results sound or unsound, conclusive or tentative, final or provisional, such as they are, they are the property of introspective psychology alone. Furthermore, there is a large class of psychological concepts framed on a combination of both kinds of evidence, subjective and objective.


  1. The "Times," January 19, 1883.
  2. Browne, "Religio Medici."
  3. Blaise Pascal (1623-'62), philosopher of no mean grasp and honesty though he was, strove to dissuade his generation from following out the Copernican system to its issues because it maintained the heretical doctrine of the movement of the earth. Pascal would not have merited censure for hesitating to accept the Copernican system had he argued on supposed philosophic grounds (Milton died uncertain which to accept, the doctrine of Ptolemy or Copernicus); his grave error consists in having preferred theological dogma to that which he felt to be truth.
  4. "Heresy," aptly styled by Lanfrey, "Cette éternelle protestation de la liberté de l'esprit humain contre les doctrines infaillibles" (That eternal protest of liberty of the human mind against infallible doctrines). "Histoire Politique des Papes," p. 70: Ed. Charpentier.
  5. Atheist and atheism are words constantly used in total ignorance of their real meaning. An angry religionist, being asked for his definition of the term atheist, unhesitatingly replied, "I call any man an atheist who does not go to my church, or some one like it." Strong in sectarian conviction, but weak in classical attainment, my friend evidently had, like one greater than he, "small Latin and less Greek," and knew as little of etymology as he felt of toleration for any creed but his own. But was he not (setting aside the question of verbal roots) a fair specimen of a large class?
  6. In explanation of his doubtingness, we must remember Descartes was not merely a metaphysician—he was likewise a physicist of high distinction. The positive tendencies fostered by physical objective study served to counterbalance within certain limits the subjective transcendental activity of his grand intellect.
  7. Prochaska, "Nervous System," quoted by Bastian, "The Brain as an Organ of Mind," p. 511. On the contrary, according to the shrewder insight of one of the most far-seeing of physiologists, Xavier Bichat, the heart, or its vicinity, holds relationship to the passions, the head to intellectual phenomena. "L'acteur," he says, "qui ferait une équivoque à cet égard, qui, en parlant de chagrins rapporterait les gestes à la tête, ou les concentrerait sur le cœur pour annoncer un effort de génie se couvrirait d'un ridicule, que nous sentirions mieux encore que nous le comprendrions" (The actor who should make a mistake in this matter, who, speaking of his griefs, should refer his gestures to his head, and who should concentrate them upon his heart in announcing an intellectual effort, would cover himself with a ridicule that we can feel better than we can comprehend).—"Vie et Mort," p. 42, Paris, 1813.
  8. Singularly enough, this speculative difficulty has occasionally proved the source of specific practical inconvenience. Thus "Turkish graves are very shallow, sometimes not more than a foot in depth, the reason for this being that most old-fashioned Turks still retain the superstition that the soul does not leave the body until some time after burial, when it is drawn from the grave by the angel of death, who would find great difficulty in performing his task if the body was too deeply buried. The consequence of this is that in warm weather a horrible stench arises from the cemeteries."—"God's Acre Beautiful," by W. Robinson, F.L.S, p. 117.
  9. The "noumenon" is an "intelligible object—that is, one which, if it is to be cognized at all, must be so in and through the understanding without any sensuous medium" (Kant's "Prolegomena," translated by Bax, p. lxxxvii). This "Ding an sich," "thing in itself," or "noumenon," is held to be the antithesis of the sensuous phenomenon, but the actual relationship of the two was to Kant himself, has been to his disciples, and will presumably prove to the end of time to his successors, the great stumbling-block in the way of thinking out Kant's whole system.
  10. Quoted by Graham, "Creed of Science," pp. 153, 154. Kant, again, sometimes uses the phrase "the thinking self," as synonymous with soul; and speaks of the "doctrine of body and the doctrine of soul—the first dealing with extended and the second with thinking, Nature."
  11. "Mind and Body," p. 153.
  12. Kant's "Prolegomena," translated by Bax, p. xxxv.
  13. E. B. Bax, ibid., p. 101.
  14. J. S. Mill, "Autobiography," pp. 275, 276, third edition, 1874.
  15. Maudsley, "Journal of Mental Science," vol. xi, p. 551.
  16. E. B. Bax, ibid., preface, p. 3.
  17. "Human Knowledge," vol. i, p. 74.
  18. So far from its being desirable that that rare form of gift or "acquired mental dexterity," as the introspective faculty is affirmed to be by Sir William Hamilton, should be vouchsafed to cultured mankind at large, the endowment may, without probable ultimate loss to real knowledge, be left in the grasp of the limited class for which its possession is claimed.