Elements of metaphysics

by A. E. Taylor

Considerations of this kind have led to the general recognition that the physical order must be regarded as phenomenal, as the manifestation to sense-perception of a reality which is in its own nature inaccessible to sense-perception, and therefore, in the strictest sense of the words, not physical. When we ask, however, how this non-physical reality of which the physical order is the phenomenal manifestation to our senses, is to be thought of, we find ourselves at once plunged into the same difficulties which we have already met, in a more general form, in discussing the concept of Substance. Popular thought, and science so far as it is content to accept the notions of popular thought without criticism, have commonly fallen back on the idea of the non-phenomenal ground of the physical order as an unperceived “substratum.” To this substratum it has given the name of matter, and has thus interpreted the physical order as the effect produced by the causal action of an unperceived matter upon our sense-organs, or rather, to speak with more precision, upon their unknown material substratum. Frequently, as might have been expected, the attempt has been made to identify this substratum with those of the known qualities of the physical order which appear least liable to modification with the varying states of the percipient organs, and lend themselves most readily to measurement and calculation, the so-called “primary” qualities of mechanical science. This is the standpoint adopted by Newton and, in the main, by Locke, and largely through the influence of their work still remains the most familiar to the ordinary English mind. But the inconsistencies we have already found inherent in such a conception of Substance as is here presupposed, so inevitably make themselves felt upon any serious examination, that the doctrine regularly appears in the history of thought as a mere temporary halting-place in the advance to the more radical notion of matter as the entirely unknown non-phenomenal substratum of the sensible properties of bodies.

§ 2. This latter notion is again manifestly open to all the objections previously brought against the more general concept of substance as an unknown substratum or support of properties. It is from these objections that Berkeley’s famous criticism of the concept of matter, the most original attempt at a constructive theory of the real nature of the physical order in the history of English Philosophy, starts. Berkeley first takes the identification of material substance with the primary qualities of body, which Locke had made current in English speculation, and shows, by insisting upon the relativity of perceived quality to percipient organ, that it is untenable. Having thus driven his opponent to surrender this identification, and to define matter as the unknown substratum of the physical order, he proceeds to argue that this notion of an unknown substratum is both useless and unintelligible. It is useless, because our knowledge of the actual properties and processes of the physical order can neither be extended nor made clearer by the addition of an unknowable; it is unintelligible, because we can give no account to ourselves of the nature of the “support” supposed to be bestowed by the substratum or the properties.

Material substance being thus dismissed as an unmeaning fiction, what is left as the reality of the physical order? According to Berkeley, nothing but the actual presentations, or “ideas,” in which the percipient subject is aware of the properties of bodies. A body is simply such a complex of presentations to a percipient; except as so presented it has no existence. As Berkeley is fond of putting it, the esse of the material thing is simply percipi, the fact of its being presented. But just when we expect Berkeley to accept the complete subjectivist contention that bodies are simply “states of the percipients’ consciousness” and nothing more, he remembers that he has to account both for the fact that we cannot perceive what we please and where we please, but that our perceptions form an order largely independent of our own choice, and for the deep-seated conviction of the common-sense mind that things do not cease to exist when my perception of them is interrupted. To reconcile his theory with these apparently conflicting facts, he has recourse, as is the custom of philosophers and others in a difficulty, to divine assistance. The continued existence of the physical world in the intervals of perception, and its systematic character and partial independence of our volition, he explains by the hypotheses that God produces perceptions in us in a fixed order, and that God continues to be aware of the system of presentations which I call the physical world, when my perception of it is suspended. The same explanation would, of course, have to be invoked to account for the existence of physical realities which no human subject perceives.[^[121]]

It is fairly obvious that the two halves of Berkeley’s theory will not fit together into a coherent whole. If the whole esse of physical things is merely percipi, there can be no reason why I should suppose them to exist at all except in so far as and so long as they are presented to my perception. The whole hypothesis of an omnipresent divine perception which remains aware of the contents that have vanished from my own perception, thus becomes purely gratuitous. It also labours under the disadvantage of being, on Berkeley’s theory, internally inconsistent. For if it is necessary to invoke the agency of God to account for the occurrence of presentations to my experience, it is not clear why we have not to suppose a second deity who causes the series of presentations in the experience of God, and so on indefinitely. On the other hand, if God’s experience may be taken as uncaused, it is not clear why my own experience might not have been taken so in the first instance, and the introduction of God into the theory avoided. Thus the logical outcome of the doctrine that the esse of physical things is merely percipi, would have been either Solipsism, the doctrine according to which I have no certain knowledge of any existence except my own, everything else being a mere state or modification of myself; or the Humian scepticism, which resolves my own existence, as well as that of the external world, into a mere sequence of fleeting mental processes. Conversely, if I have adequate reason to believe that any member of the physical order whatever is more than a presentation, and has an existence in some sense independent of my perception, I have no right to declare of any member of that order, unless for special reasons, that its being consists merely in being perceived.

§ 3. Why, then, did Berkeley, as a matter of fact, accept neither the solipsist nor the sceptical conclusion? Why does he, after all, credit the members of the physical order with an existence independent of the fact of my perceiving them, and thus introduce a patent contradiction into his system? It is not hard to see the reasons by which he must have been influenced. The whole physical order cannot be dismissed as a mere subjective illusion, because there are some members of it which undoubtedly have an existence independent of the fact of being perceived by my sense-organs. Such members are my own body and the bodies of my fellow-men.

Both my own body and those of my fellow-men, as they are perceived by the various special senses, belong to the physical order, and share its qualities. But over and above its existence as a member of the perceived physical order, my own body has further another quite different kind of existence. It is, in so far as I perceive its parts, as I do other bodily existence, by the sensations of the various special sense-organs, a complex of presentations, like everything else in the physical world. But my body is not merely an object presented to me by the organs of the special senses; it is also something which I feel as a whole in common or organic sensation, and in the changing organic thrills of my various emotional moods. This unique feeling of my body as a whole accompanies every moment of my conscious life and gives each its peculiar tone, and there seems to be no doubt that it forms the foundation of the sense of personal identity. If we recollect the essentially teleological character of feeling, we shall be inclined to say that my body as thus apprehended is nothing other than myself as a striving purposive individual, and that my experience of it is the same thing as the experience of my purposive attitudes towards my environment. It is, in fact, this experience of my body as apprehended by immediate feeling, that Psychology describes as the “subject” of the various “mental states” of which it formulates the laws. For Metaphysics, it does not seem too much to say, this double existence of my own body, as a presented object about which I have knowledge in the same way as about everything else, and as an immediately felt unity, affords the key to the whole problem of the “independent” existence of a reality beyond my own presentations. To see how this comes about, we must first consider the influence it has on our conception of one very special part of the physical order, the bodies of our fellows.

The bodies of our fellow-men are, of course, from one point of view complexes of presentations which we receive through our sense-organs; so far their esse, as Berkeley would have said, is percipi. But all practical communion with my fellows through the various institutions of society is based upon the conviction that, over and above their existence as presentation-complexes, or contents of my perceptive states, the bodies of my fellows have the same kind of existence as directly apprehended in immediate feeling which I ascribe to my own. In other words, all practical life is a mere illusion, unless my fellow-men are, like myself, centres of purposive experience. By the existence independent of my own perception which I ascribe to them, I mean precisely existence as feeling purposive beings. Hence, unless all social life is an illusion, there is at least one part of the physical order, external to myself, of which the esse is not mere percipi, but percipere, or rather sentire. If my fellow-men are more than complexes of presentations or “ideas in my head,” then the subjectivist reduction of all reality to states of my “consciousness” breaks down, at least for this part of the physical order. Hence the acceptance or rejection of the subjectivist theory will ultimately depend on the nature of the evidence for the independent existence of human feelings and purposes beyond my own.

On what grounds, then, do we attribute such “independent” existence as experiencing subjects to our fellows? According to the current subjectivist explanation, we have here a conclusion based on the argument from the analogy between the structure of my own body, as presented in sense-perception, and those of others. I infer that other men have a mental life like my own, because of the visible resemblances between their physical structure and my own, and this inference receives additional support from every fresh increase in our anatomical and physiological knowledge of the human frame. But, being an argument from analogy, it can never amount to a true scientific induction, and the existence of human experience, not my own, must always remain for the subjectivist a probability and can never become a certainty.

I am convinced that this popular and superficially plausible view is radically false, and that its logical consequence, the belief that the real existence of our fellows is less certain than our own, is a grave philosophical error. That the argument from analogy is no sufficient basis for the belief in human experience beyond my own, can easily be seen from the following considerations:—(1) As ordinarily stated, the data of the supposed inference do not actually exist. For what I perceive is not, as the subjectivist assumes, three terms—my own mental life, my own anatomical structure, and the anatomy of my neighbour, but two, my own mental life and my neighbour’s anatomy. If I cannot be sure of the reality of my neighbour’s experience until I have compared the anatomy and physiology of his organism with that of my own, I shall have to remain in doubt at least until science can devise a mechanism by which I can see my own nervous system. At present one of the terms on which the analogical argument is said to be based, namely, my own internal physical structure, has to be mostly taken on trust. It would be little less than the truth to invert the subjectivist’s position, and say that, until science can devise means for seeing our own brains, we infer the resemblance of our own anatomy to our neighbour’s from the previously known resemblance of his inner experience and ours.

(2) And even supposing this difficulty already surmounted, as it conceivably will be in the future, there is a still more serious flaw in the presumed analogical inference. If I once have good ground for the conviction that similarity of inner experience is attended by similarity of physical structure, then of course I can in any special case treat the degree of structural resemblance between one organism and another as a sufficient reason for inferring a like degree of resemblance between the corresponding inner experiences. But upon what grounds is the general principle itself based? Obviously, if my own inner experience is the only one known to me originally, I have absolutely no means of judging whether the external resemblances between my own organism and yours afford reason for crediting you with an inner experience like my own or not. If the inference by analogy is to have any force whatever in a particular case, I must already know independently that likeness of outward form and likeness of inner experience at least in some cases go together. The plausibility of the usual subjectivist account of the way in which we come to ascribe real existence to our fellows, is simply due to its tacitly ignoring this vital point.