Art. XVII.—On the Doctrine of Mind-Stuff.
The objects of the present paper are, to describe briefly a theory or doctrine of existence, expounded by the late Prof. Clifford, in an article "On the Nature of Things in Themselves," but arrived at independently by several persons—amongst others by myself, as far back as the year 1870,—and to propound and assist toward the solution of a series of problems which arise in connection with this theory.
The starting-point of the theory is the position, commonly associated with the names of Berkeley and Hume, that all the properties of material objects, as investigated by the physical and natural sciences, are capable of being analysed into possibilities of feeling, or relations among possibilities of feeling. Thus the redness of a rose is the possibility of a certain visual sensation, and the roundness of an orange is a complex of relations among the possibilities of certain visual, tactual, and muscular sensations. Granting this position, it obviously follows that every assertion of physical science—every assertion, that is, respecting matter, force, or motion—is merely an assertion respecting possibilities of sensation or feeling. The truth of this position is demonstrated by a process of self-observation or introspection, and must be verified by each individual for himself. It is believed by the present waiter that the conclusion arrived at cannot be resisted by any mind which performs the requisite process of self-analysis with perfect precision and faithfulness.
The only concrete realities, therefore—the only "things-in-themselves" that we know of, are feelings. Psychology is the only concrete science. The word "feeling" is used here to denote any mental state whatever. page 206 The feelings or mental states of which we have experience comprise the comparatively vivid ones known as sensations and emotions, the fainter copies of these, sometimes called "ideas," which constitute the material of which thought is woven, and certain unique states of mind which form integral parts of volition and belief—states of mind which assimilate most nearly to emotions, but which may be described as somewhat too colourless, if the term be allowable, to be fairly classed with these.
All the real existences we know of being mental states, the totality of existence falls for each individual into two sections: his own mental states, i.e. mental states which form a part of his own consciousness, and mental states not his own. The former constitute a stream or chain, extending from a past that is more or less remote into a future almost wholly unknown; his present condition of mind being a transverse section of the stream, or a link in the chain. His knowledge of the portion anterior to the present moment is obtained partly by the faculty of memory, and partly by a system of inferences; his anticipations as to the portion that is still future are grounded entirely on inference.
Now, by a process essentially identical with that by which he infers these future portions, and some of the past portions, of his own stream or chain of consciousness, each individual comes to believe, at a very early stage of his career, in the existence of other streams or chains of consciousness which are more or less like his own, but which are entirely outside it. He believes that his fellow-creatures are conscious beings, and that the higher animals are sentient. The process by which this conclusion is reached, and by which it may be justified, is fully described by Mr. Mill in a well-known passage of his "Examination of Sir William Hamilton's Philosophy." There is a further inference drawn which is of great importance, and which I hope will engage our attention in a future paper. The inference is drawn that there exist relations of sequence and of synchronism between his own feelings and the feelings which compose the other streams of consciousness. These relations had already been recognized among his own feelings, and might easily be inferred as existing among the feelings of any other one stream of consciousness taken by itself. But it might seem a more perilous step to infer cross-relations of this kind between different streams; nevertheless, this inference, endorsed every hour a thousand times by the common sense of mankind, is one which I think can be shown to be logically justifiable. Without, however, dwelling any longer on this point, we may note that each individual conceives of other streams of consciousness as running parallel to his own in Time, and that their outsideness to his own consciousness is quite a different thing from the apparent outsideness of any material body. A material body, or, as it is usually called in page 207 the language of metaphysics, an object (even if it be the farthest fixed star) is an abstraction the primary reference of which is to a concrete something inside the individual's consciousness, namely a certain group of his own sensations; while its appearance of externality is derived from the fact that it also refers to actual or possible sensations outside his consciousness, namely in the consciousness of other beings who do or might exist. These other streams of consciousness, and not the earth, air, and sky, are the true "External World" to each individual. The outsideness or externality of these "other streams of consciousness," of which each one among us infers the existence, and of the feelings composing them, appears to me to be very happily expressed in the term by which Prof. Clifford has proposed to denote them, namely the term eject. The minds of my readers are "ejects" to me, and my mind is an "eject" to them. The use of this term also places in marked contrast the genuine outsideness of these inferred existences with the pseudo-externality, so to speak, of the material universe.
So far, nothing new has been enunciated. The thinkers of the school to which I belong, maintain that, paradoxical as some of the above assertions may sound, (for instance, the denial of the concrete existence of matter,) the common sense of mankind will bear us out in them, if only its deliverances be analysed and formulated with precision. It is only when we take a further step that our doctrine parts company with the belief of the uninstructed. This further step is taken in answer to the question: "Are there ejects which form no part of any consciousness? Are there non-personal ejects?" and to the further question: "If so, what is their nature? "
Are there ejects which form no part of any consciousness? In other words, besides the consciousnesses of intelligent beings, each with its rich phantasmagoria of sensations, and its varied wealth of ideas and emotions, are there any real existences? My readers will immediately reply, "To be sure. There is the earth, with all the material objects on its surface, there are the sun, moon, and stars, and, in fact, the whole material universe?" This, however, would be a reply which would not meet the question at all. For, as indicated in the first portion of this paper, if any one will honestly examine the nature of his conceptions respecting material objects, he will find that they resolve themselves wholly into conceptions of possibilities of sensation in himself and in other sentient beings who do, or might, exist: and, if all these possibilities of sensation be abstracted, he will be much puzzled to attach a meaning to the assertion that there is a residuary existence behind. It will not suffice, therefore, to answer the question by merely affirming the existence of a material universe: we must also state whether we believe that, besides the possibilities of sensation, and the relations page 208 among these, which constitute the whole content of physical science, there exists a universe of realities inaccessible to physical science, on which the possibilities of sensation are dependent. In the language of metaphysics the question may be thus stated:—Does the phenomenal world, or world of appearances, correspond to and depend for its existence on a noumenal world, or world of realities, wholly outside us? The answer given by the majority of metaphysicians is, I believe, that there does exist such a world of realities, but that its nature must be for ever hidden from us.
Physical science, they would say, investigates the properties of things as they appear to us—investigates the outsides of things, so to speak; but things as they are in themselves, the inner nature or insides of things (though we may be certain of their existence, whether intuitively or as a result of legitimate inference), are inaccessible to human research. This I take to be the doctrine of Kant, and also the doctrine of Herbert Spencer. Now, the doctrine I wish to describe this evening, is partly in agreement with the foregoing doctrine, and partly in disagreement with it. There is a universe of realities, it affirms, underlying the phenomena which it is the business of physical science to investigate, but its nature is not wholly unknown to us. For let us consider a particular section of physiological phenomepa—the phenomena of the human brain. In the changes which take place, during life, in the grey matter of the brain, we have a field for physical research. These changes belong to the world of phenomena—to the world of " things as they appear to us." They may be described in the language of physical science, and statements respecting them would resolve themselves, in last analysis, into statements of possibilities of sensation, and relations among those possibilities, in the mind of a supposed observer. But now, according to both the doctrines we are considering, this complex of phenomena—this group of changes in the grey matter of the brain—must have a complex of noumena, or "things-in-themselves," underlying it. "What is this complex of " things-in-themselves?" It is not an object of physical research. Physical research stops at the changes in the grey matter of the brain-estops at a group of appearances. What is the complex of "things-in-tliemselves" which underlies these appearances? Now we know, or at least have very strong ground for believing, that some of the changes in the grey matter of the brain correspond to feelings or thoughts in the mind of the person to whom the brain belongs. According to the doctrine of Mind-Stuff, these feelings or thoughts are the noumena—the " things-in-themselves "—which underlie the changes in the grey matter of the brain. What appears to an outside observer—or rather, what would appear to him, were the skull transparent, as a change in the grey matter of the brain—is in reality a feeling or thought in the mind of the person to whom the brain page 209 belongs. This feeling or thought is not an object of physical research. It belongs to the world of noumena, or "things-in-themselves," with which physical science has no concern, or with which it is only concerned in so far as the hypothesis of the existence of such a world is required to account for that world of phenomena, the laws of which it is the business of physical science to investigate. Thus we see that in regard to at any rate one part of it, it is not true to say that the noumenal world is veiled from us. We know it by introspection; and we know it as feeling or thought. We are ourselves—our minds, I mean, not our bodies—strands in the web of the noumenal world; and therefore, although no part of that world can ever be investigated by physical science, we see that a portion of it forms the subject-matter of subjective psychology, and is consequently not altogether unknown to us. Of course it is only one's own consciousness which one knows with any great precision. I do not know whether the sensation which my neighbour calls green is qualitatively quite the same as that which I myself call green. The phenomena of colour-blindness demonstrate conclusively that in some cases it is not. Still, I have, in a general way, an acquaintance with the consciousness of my fellow-creatures and of the higher animals. They constitute the portion of the noumenal world which we obviously know something about—something which physical science could never tell us.
And now, what are we to say about the rest of the noumenal world—the remaining strands of the web? There is a remaining portion, for we have agreed that there are noumena or realities underlying the phenomena of inorganic and of non-cerebral organic nature. What are these realities like? Now, the doctrine of Mind-Stuff asserts that these realities are made up of the same stuff or elements as the human mind, only that the elements are combined together in a less complicated way. The universe, according to this view, is a stupendous web of mind-stuff, the elementary strands of which are ever weaving themselves into new patterns from eternity to eternity. The most complex of the compound strands are the minds of intelligent beings, and from these there is every degree of complexity down to the elementary strands themselves, which correspond to the motions of inorganic matter. Whether the elements of the noumenal world are described as being themselves feelings, or only as the elementary constituents of feelings, appears to me to be merely a question of language. If we adopt the former phraseology, the doctrine may fitly be called that of Omnisentiency. This was the name given to it by a former fellow-student, Mr. William Boulting, now a member of the medical profession in England, and myself, when we arrived at it, independently but almost simultaneously, in the year 1870. Although it appears that we have been anticipated by page 210 Professor Wundt, the eminent German physiologist, and perhaps by others, we may claim as much originality as any of the exponents of the doctrine, and priority over most.
I now turn to some of the problems which are suggested by the general theory of things we have been considering.
First: In what relation does the doctrine of Omnisentiency or Mind-Stuff stand to the various theories which have been propounded for explaining, on the principles of rational mechanics, the phenomena of the physical universe? In what relation does it stand to the theories of atoms, ether, ultramundane corpuscles, ring-vortices, and the like? Now, in the first place, it does not either exclude or supersede them. There is nothing in the doctrine of Mind-Stuff incompatible with any of these mechanical theories. The theories in question are one and all of them statements of quantitative relations among possibilities of feeling, and are not in any way concerned with the noumenal realities on which these possibilities depend. The universe of matter is a complex of possibilities of feeling, and these possibilities are found to stand in certain quantitative relations to one another. These relations are of two orders,—relations of sequence and relations of co-existence. The former are believed to depend, without exception, on causal relations—relations spoken of as the laics of nature;—the latter are space-relations, and may be described as facts of structure. All the mechanical theories I have alluded to, therefore, and indeed all mechanical theories that can be framed, are affirmations either of mechanical laws or facts of structure, or both. Setting out from the relations of sequence and facts of structure which we observe to exist among the possibilities of sensation which constitute the material world, the physical investigator does one of two things. He either infers, by a complete induction, the existence of such and such causal relations, and then deduces facts of structure which are not capable of being observed; or, he assumes the existence of certain facts of structure, and perhaps also of certain causal relations, and shows that by known causal relations these will lead to the observed facts of structure. In the former case, his process is one of scientific demonstration, in the latter he constructs a scientific hypothesis. To the former category belongs the reasoning by which we infer that matter consists of molecules (in other words, that its structure is discontinuous), and that there is an ether; to the latter, belong such hypotheses as those of ring-vortices and ultra-mundane corpuscles. But now, observe, we are throughout dealing with quantitative relations among abstract possibilities. The whole of mechanical science deals with such relations. It is in no way concerned with the inner qualitative nature of the real existences on which these possibilities depend. These real existences are aggregations of Mind-Stuff. page 211 Psychology is the only science which deals with them; and even that deals only with the most complex of them. Therefore the Doctrine of Mind-Stuff can in no way supersede the necessity of, still less can it exclude, these mechanical explanations of the universe.
But although the principles of rational mechanics, and the hypotheses by which, in conjunction with the former, it is sought to explain the observed phenomena and structure of the material world, are in no way in conflict with our doctrine, we shall presently see that they may come to have a very important bearing on the determination of the particular form which that doctrine ought to assume. For the doctrine assorts that the possibilities of sensation which constitute a material object, correspond to, and depend for their existence on, some reality outside us or "eject" of which Mind-Stuff units are the elementary constituents. Hence every conception of mechanical science must denote what would be called in mathematics some function of Mind-Stuff. Matter, defined as that which has mass or inertia, must be a function of Mind-Stuff. Motion, force, and energy, must be functions of Mind-Stuff. The interesting question then suggests itself: What functions, severally, are mass, momentum, energy, etc., of the noumenal reality which we have designated Mind-Stuff. This question has been touched upon in a profound passage of the late Professor Clifford's review of a work entitled "The Unseen Universe." Professor Clifford there indicates that the answer to the question, if it can be answered, must depend on the knowledge we can gain respecting Mind-Stuff itself—knowledge which can only be acquired within the domain of psychology. Our feelings, he points out, have certain relations of contiguity or nextness in space, exemplified by contiguous elements of a visual image, and certain relations of sequence in time, exemplified by all feelings whatever. "Out of these two relations the future theorist must build up the world as best he may. Two things may, perhaps, help him: there are several lines of mathematical thought which seem to indicate that distance and quantity may come to be expressed in terms of position, in the wide sense of an analysis situs, while the theory of the curvature of space hints at a possibility that matter and motion may be expressed in terms of extension only."*
* I take this to mean, that if we admit as a possibility that the properties of space may show a sensible divergence from the Euclidean standard, if we consider very small parts of it—we get at a way of defining matter in terms of the space which it occupies. An ultimate atom of matter (perhaps infinitesimal as compared with the chemical atom) would on that view be merely an infinitesimal crumple in space. All physical science would then be reduced to transcendental geometry, and space-elements would be the analogues of Mind-Stuff units.
The former parts of Professor Clifford's suggestion can only mean, as far as I can see, that space may be not only not homogeneous in ultimate structure, but not even infinitely divisible. It may consist of indivisible units. In that case there would be such a thing as absolute magnitude, and measuring would be reduced to counting. The space-unit would then be the analogue of the Mind-Stuff unit.
Now it is my ambition to follow out the line of thought here indicated. It would be impossible to do so fully within the limits of a single paper, but a beginning may be made. In the first place I desire to supply what I conceive to be a serious omission in Professor Clifford's enumeration of the data respecting Mind-Stuff which the "future theorist" has at his disposal. Feelings not only have relations of contiguity or nextness in space, and of sequence in time, but they also have two other quantitative aspects of very great importance, namely degrees of intensity and differences of volume. We are conscious that sensations differ in intensity; thus an acute pain is felt to be a more intense sensation than a faint smell. Also, we are conscious that sensations of about equal intensity differ in something we call volume or massiveness: thus a sensation of general weariness, though perhaps felt to be of about equal intensity with a particular ache, is distinguished (apart from its qualitative difference) as possessing greater mass or volume. Lastly, we know that there exist causal relations among our feelings. Thus the group of ideas* characterized as the realization of a danger is followed by the emotion of terror, and the constancy of the sequence indicates that we have here to deal with a causal relation. Hence the data we possess are these:—a complex of feelings perpetually undergoing transformations, causal relations between successive feelings, relations of contiguity or nextness among a few of the synchronous ones (though this appears to be an exceptional phase of psychic structure, only to be found, as far as I am aware, among simultaneous visual impressions which co-exist in a space or manifoldness of two dimensions), qualitative resemblances and differences, variations in intensity, and variations in volume or mass. These are the materials from which we must construct our conception, save as to certain spots necessarily a very dim one, of the noumenal world. And these are the materials which we must connect, in the best way we can, with the elementary factors of our conception of the world of phenomena. We must endeavour to establish a correspondence between feelings, their causal and topical relations, their intensities and volumes, on the one hand, and the dynamical conceptions of mass, momentum, force, energy, etc., on the other. Now, as a preliminary to the working out of this correspondence it will perhaps be advisable to take a brief survey of the ultimate dynamical conceptions, and of their relations to one another.
* An idea is merely a combination of derivative feelings which are severally faint copies of more vivid primary feelings. In the present case there is included also an unique element called belief alluded to in an earlier portion of this paper.
Our first step will show us how thoroughly interdependent all these conceptions are. Matter can only be defined as that which possesses inertia—as that which requires a force proportional to its amount (designated its mass) to effect a given change in its motion (either a change in velocity, or a change in direction, or both) in a given time. Force, again, can only be defined as that which causes a change in the velocity or direction of the motion of matter. It is tacitly assumed, though not often expressed, that the only thing which can cause such a change in velocity or direction is the co-existence of other matter. This amounts to saying that force is a relation of co-existence between different portions of matter. But every relation of co-existence in the material or phenomenal world is a relation of mutual position in space. Hence force is a relation of mutual position between different portions of matter. Motion, in the kinetic, or dynamical, as opposed to the merely kinematical sense, is a change in the position of matter, and is completely determined when the mass of the moving body and the kinematical conditions of the case are given. The notion of energy does not require the introduction of any fundamentally new conception. Hence the phenomenal world is accurately described if we speak of it as a complex of motions, varying in infinite ways as regards mass on the one hand, and velocity and the other kinematical aspects on the other, tending severally to constancy in all these respects, but having a mutual action on one another, determined by their relations of co-existence, and, therefore, undergoing perpetual transformations. Now mark the parallelism. The noumenal world, we have seen, may be described as a complex of feeling-elements, or Mind-Stuff units, having, just as motion has, extension in Time, varying in infinite ways as regards volume, intensity, and quality or timbre, having a mutual action on one another, determined by their mutual relations of co-existence, and undergoing perpetual transformations. Is this parallelism something more than a parallelism? Without attempting to justify it in this paper, I would hazard the conjecture that motion is Mind-Stuff, that volume of feeling is mass, and intensity of feeling velocity. Professor Clifford seems to have believed that motion and Mind-Stuff were identical, and indeed to have held the belief in a much more dogmatic form than I should be inclined to do; but the other two identifications are, as far as I am aware, quite new. The degree of light which cerebral physiology may be capable of throwing on the question must be estimated by abler minds than my own: but one implication of my hypothesis has struck me as favourable to it. If matter in Motion be Mind-Stuff, it follows that if matter were ever at absolute rest, it would no longer correspond to any noumenal existence. It would become a pure abstraction—one term of a product, the other term of which was zero. Does not this appear in harmony with the hypothesis of Sir Wm. page 214 Thomson, which makes all the atoms of ordinary matter, and all the particles of which the ether is composed, to consist of a rotational motion in an incompressible frictionless fluid? The stoppage of the vortex-motion would be the obliteration of both atoms and ether—the annihilation of the sensible universe. The perfect fluid at rest would be, on my view, a mere nullity. No noumenal existence would correspond to it, and it would, in fact, merely represent the potentiality of massiveness among feelings.
Two other identifications will at once suggest themselves, and may be relied on with greater confidence than any of the three preceding ones: First, the causal relations among elements of feeling will have their counterparts in the causal relations among motions of matter, i.e., they will have their counterparts in the dynamical laws of the universe. And secondly, the relations of synchronism among elements of feeling will have their counterparts in the relations of synchronism among the motions of matter, i.e., they will have their counterparts in the space-relations of the universe. Certain passages in Herbert Spencer's "Principles of Pyschology" seem to indicate that he entertains a similar belief.
And now, one more thing follows. The nexus of causation which obtains among the feeling-elements, or Mind-Stuff units, i.e., among the elements of the noumenal world, must be at least as complex as the corresponding nexus which obtains among the motions of matter, i.e., among the elements of the phenomenal world; and it may be indefinitely more so. For the phenomenal world depends for its existence on the noumenal world, and is in fact only a particular aspect of the latter—that aspect, namely, which the noumenal world presents to its own most complex strands, the percipient beings that grow up in its bosom. Nor can the elements of the phenomenal world derive any complexity from the interaction of the noumenal elements which they represent with the complex structure of the precipients. For it is the especial triumph of the mechanical theory of the universe to have eliminated all these complexities, and referred the affections of the various senses to the same source. Thus the sensations of light and warmth we receive from a fire, are both referred to the radiant energy of the ether which intervenes between the fire and ourselves. Hence we may be certain that the nexus of causation in the noumenal world is at least as complex as the dynamical nexus of the phenomenal world. But it may be indefinitely more so. There may be many causal relations in the noumenal world which have no types in the phenomenal world, though we may be certain that every dynamical relation in the phenomenal has its anti-type in the noumenal world. The phenomenal world is a projection, so to speak, of the noumenal world on the plane of observation, and much complexity may be lost in the process of projection. In the same way the space-relations of the pheno- page 215 menal world must be paralleled by a nexus, at least equally complex, of synchronous relations in the noumenal world. But the complexity of the latter may be greater by any amount than that of the former. There may be facts of structure in the noumenal world which have no representatives, so to speak, in the world of phenomena. It has always seemed to me probable that this was the truth which Spinoza had in his mind when he said that extension was only one out of a perhaps infinite number of attributes possessed by the universal substance. The possibility in question shows that there is nothing in the doctrine of Mind-Stuff per se—Professor Clifford to the contrary notwithstanding—to negative the belief either of the spiritualist or of the theologian. It may or may not be the tendency of physiological research to exclude the conceptions with which these two classes of thinkers are concerned, but this exclusion can certainly not be the result of an acceptance in its most general form of the doctrine here described. On the other hand, there is equally little in it to encourage or lend assistance to theological belief. The proposition that there is a dim quasi-sentiency pervading the world, is as far removed as possible from the proposition that there are intelligences unconnected with any brain, and this latter proposition, which is the essence of all spiritualism and theology, can derive no support from the former. In regard to theology, then, the doctrine of Mind-Stuff is neutral. It may rather be described as monistic than as materialistic. It affirms that there is only one Existence—that which Herbert Spencer* speaks of as the "Substance of Mind"—and that the supposed dualism of matter and spirit is an illusion.