(a) It is sometimes maintained that Metaphysics is an impossibility because the metaphysician’s problems, in their own nature, admit of no solution. To a meaningless question, of course, there can be no intelligible answer, and it is occasionally asserted, and often insinuated, that the questions of Metaphysics are of this kind. But to call the metaphysician’s question a senseless one is as much as to say that there is no meaning in the distinction, which we are all constantly making, between the real and the apparent. If there is any meaning at all in the distinction, it is clearly a necessary as well as a proper question precisely by what marks the one may be distinguished from the other. Our right to raise this question can in fairness only be challenged by an opponent who is prepared to maintain that the contradictions which lead us to make the distinction may themselves be the ultimate truth about things. Now, whether this view is defensible or not, it is clearly not one which we have the right to assume without examination as self-evident; it is itself a metaphysical theory of first principles, and would have to be defended, if at all, by an elaborate metaphysical analysis of the meaning of the concepts “truth” and “reality.” Again, the objection, if valid, would tell as much against experimental and mathematical science as against Metaphysics. If the self-contradictory can be true, there is no rational ground for preferring a coherent scientific theory of the world to the wildest dreams of superstition or insanity. Thus we have no escape from the following dilemma. Either there is no rational foundation at all for the distinction between reality and appearance, and then all science is an illusion, or there is a rational foundation for it, and then we are logically bound to inquire into the principle of the distinction, and thus to face the problems of Metaphysics.[[4]]
(b) What is essentially the same objection is sometimes put in the following form. Metaphysics, it is said, can have no place in the scheme of human knowledge, because all intelligible questions which we can ask about reality must fall within the province of one or other of the “sciences.” There are no facts with which some one or other of the sciences does not deal, and there is therefore no room for a series of “metaphysical” inquiries over and above those inquiries which constitute the various sciences. Where there are facts to investigate and intelligible questions to be put, we are, it is contended, in the domain of “science”; where there are none, there can be no knowledge. Plausible as this argument can be made to appear, it is easy to see that it is fallacious. From the point of view of pure Logic it manifestly contains a flagrant fallacy of petitio principii. For it simply assumes that there is no “science,” in the most universal acceptation of the term—i.e. no body of reasoned truth—besides those experimental sciences which have for their object the accumulation and systematisation of facts, and this is the very point at issue between the metaphysician and his critics. What the metaphysician asserts is not that there are facts with which the various special branches of experimental science cannot deal, but that there are questions which can be and ought to be raised about the facts with which they do deal other than those which experimental inquiry can solve. Leaving it entirely to the special sciences to tell us what in particular are the true facts about any given part of the world’s course, he contends that we still have to ask the more general question, what we mean by “real” and “fact,” and how in general the “real” is to be distinguished from the unreal. To denounce the raising of this question as an attempt to exclude certain events and processes from the “province of science,” is simply to misrepresent the issue at stake. Incidentally it may be added, the objection reveals a serious misunderstanding of the true principle of distinction between different sciences. The various sciences differ primarily, not as dealing with different parts of the world of reality, but as dealing with the whole of it so far as it can be brought under different aspects. They are different, not because they deal with different sets of facts, but because they look at the facts from different points of view. Thus it would be quite wrong to suppose that the difference between, e.g., Physics, Physiology, and Psychology, is primarily that each studies a different group of facts. The facts studied may in great part be the same; it is the point of view from which they are regarded by which each of the three sciences is distinguished from the others. Thus every voluntary movement may be looked at either as a link in a series of displacements of mass-particles (Physics), as a combination of muscular contractions initiated from a centre in the cortex of the brain (Physiology), or as a step to the satisfaction of a felt want (Psychology). So Metaphysics does not profess to deal with a certain group of facts lying outside the province of the “sciences,” but to deal with the same facts which form that province from a point of view which is not that of the experimental sciences. Its claim to do so can only be overthrown by proving what the criticism we are considering assumes, that there is no intelligible way of looking at the facts besides that of experimental science.
(c) More commonly still the intrinsic intelligibility of the metaphysician’s problem is admitted, but our power to solve it denied. There may be, it is said, realities which are more than mere appearance, but at any rate with our human faculties we can know nothing of them. All our knowledge is strictly limited to appearances, or, as they are often called, phenomena.[[5]] What lies behind them is completely inaccessible to us, and it is loss of time to speculate about its nature. We must therefore content ourselves with the discovery of general laws or uniformities of the interconnection of phenomena, and dismiss the problem of their real ground as insoluble. This doctrine, technically known as Phenomenalism, enjoys at the present time a widespread popularity, which is historically very largely due to an imperfect assimilation of the negative element in the philosophy of Kant. Its merits as a philosophical theory we may leave for later consideration; at present we are only concerned with it as the alleged ground of objection against the possibility of a science of Metaphysics. As such it has really no cogency whatever. Not only do the supporters of the doctrine constantly contradict their own cardinal assumption (as, for instance, when they combine with the assertion that we can know nothing about ultimate reality, such assertions as that it is a certain and ultimate truth that all “phenomena” are connected by general laws, or that “the course of nature is, without exception, uniform”), but the assumption itself is self-contradictory. The very statement that “we know only phenomena” has no meaning unless we know at least enough about ultimate realities to be sure that they are unknowable. The phenomenalist is committed to the recognition of at least one proposition as an absolute and ultimate truth, namely, the proposition, “I know that whatever I know is mere appearance.” And this proposition itself, whatever we may think of its value as a contribution to Philosophy, is a positive theory as to first principles the truth or falsity of which is a proper subject for metaphysical investigation. Thus the arguments by which it has been sought to demonstrate the impossibility of Metaphysics themselves afford unimpeachable evidence of the necessity for the scientific examination of the metaphysical problem.[[6]]
§ 7. With the other two anti-metaphysical contentions referred to at the beginning of the last section we may deal much more briefly. (2) To the objector who maintains that Metaphysics, if possible, still is useless, because the sciences and the practical experience of life between them already supply us with a coherent theory of the world, devoid of contradictions, we may reply: (a) The fact is doubtful. For, whatever may be said by the popularisers of science when they are engaged in composing metaphysical theories for the multitude, the best representatives of every special branch of mathematical and experimental science seem absolutely agreed that ultimate questions as to first principles are outside the scope of their sciences. The scope of every science, they are careful to remind us, is defined by certain initial assumptions, and what does not fall under those assumptions must be treated by the science in question as non-existent. Thus Mathematics is in principle restricted to dealing with the problems of number and quantity; whether there are realities which are in their own nature non-numerical and non-quantitative[[7]] or not, the mathematician, as mathematician, is not called upon to pronounce; if there are such realities, his science is by its initial assumptions debarred from knowing anything of them. So again with Physics; even if reduced to pure Kinematics, it deals only with displacements involving the dimensions of length and time, and has no means of ascertaining whether or not these dimensions are exhibited by all realities. The notion that the various sciences of themselves supply us with a body of information about ultimate reality is thus, for good reasons, rejected by their soundest exponents, who indeed are usually so impressed with the opposite conviction as to be prejudiced in favour of the belief that the ultimately real is unknowable. (b) Again, as we have already seen, the results of physical science, and the beliefs and aspirations which arise in the course of practical experience and take shape in the teachings of poetry and religion, often appear to be in sharp antagonism. “Science” frequently seems to point in one direction, our deepest ethical and religious experience in another. We cannot avoid asking whether the contradiction is only apparent or, supposing it real, what degree of authority belongs to each of the conflicting influences. And, apart from a serious study of Metaphysics, this question cannot be answered. (c) Even on the most favourable supposition, that there is no such contradiction, but that science and practical experience together afford a single ultimately coherent theory of the world, it is only after we have ascertained the general characteristics of ultimate reality, and satisfied ourselves by careful analysis that reality, as conceived in our sciences, possesses those characteristics, that we have the right to pronounce our theory finally true. If Metaphysics should tum out in the end to present no fresh view as to the nature of the real, but only to confirm an old one, we should still, as metaphysicians, have the advantage of knowing where we were previously only entitled to conjecture.
(3) The charge of unprogressiveness often brought against our science is easily disproved by careful study of the History of Philosophy. The problems of the metaphysician are no doubt, in a sense, always the same; but this is equally true of the problems of any other science. The methods by which the problems are attacked and the adequacy of the solutions they receive vary, from age to age, in close correspondence with the general development of science. Every great metaphysical conception has exercised its influence on the general history of science, and, in return, every important movement in science has affected the development of Metaphysics. Thus the revived interest in mechanical science, and the great progress made in that branch of knowledge which is so characteristic of the seventeenth century, more than anything else determined the philosophical method and results of Descartes; the Metaphysics of Leibnitz were profoundly affected by such scientific influences as the invention of the calculus, the recognition of the importance of vis viva in dynamics, the contemporary discoveries of Leuwenhoeck in embryology; while, to come to our own time, the metaphysical speculation of the last half-century has constantly been revolving round the two great scientific ideas of the conservation of energy and the origin of species by gradual differentiation. The metaphysician could not if he would, and would not if he could, escape the duty of estimating the bearing of the great scientific theories of his time upon our ultimate conceptions of the nature of the world as a whole. Every fundamental advance in science thus calls for a restatement and reconsideration of the old metaphysical problems in the light of the new discovery.[[8]]
§ 8. This introductory chapter is perhaps the proper place for a word on the relation of Metaphysics to the widely diffused mental tendency known as Mysticism.[[9]] Inasmuch as the fundamental aim of the mystic is to penetrate behind the veil of appearance to some ultimate and abiding reality, there is manifestly a close community of purpose between him and the metaphysician. But their diversity of method is no less marked than their partial community of purpose. Once in touch with his reality, wherever he may find it, the mere mystic has no longer any interest in the world of appearance. Appearance as such is for him merely the untrue and ultimately non-existent, and the peculiar emotion which he derives from his contemplation of the real depends for its special quality on an ever-present sense of the contrast between the abiding being of the reality and the non-entity of the appearances. Thus the merely mystical attitude towards appearance is purely negative. The metaphysician, on the contrary, has only half completed his task when he has, by whatever method, ascertained the general character of the real as opposed to the merely apparent. It still remains for him to re-examine the realm of appearance itself in the light of his theory of reality, to ascertain the relative truth which partial and imperfect conceptions of the world’s nature contain, and to arrange the various appearances in the order of their varying approximation to truth. He must show not only what are the marks of reality, and why certain things which are popularly accepted as real must, for Philosophy be degraded to the rank of appearance, but also how far each appearance succeeds in revealing the character of the reality which is its ground. Equally marked is the difference between the mystic’s and the metaphysician’s attitude towards ultimate reality itself. The mystic’s object is primarily emotional rather than intellectual. What he wants is a feeling of satisfaction which he can only get from immediate contact with something taken to be finally and abidingly real. Hence, when he comes to put his emotions into words, he is always prone to use the language of vague imaginative symbolism, the only language suitable to suggest feelings which, because immediate and unanalysed, cannot be the subject of logical description in general terms. For the metaphysician, whose object is the attainment of intellectual consistency, such a method of symbolism is radically unsuitable.
A symbol is always a source of danger to the intellect. If you employ it for what you already understand, and might, if you chose, describe in scientific language, it is a mere substitution of the obscure for the clear. If you use it, as the mystic commonly does, for what you do not understand, its apparent precision, by blinding you to the vagueness of its interpretation, is positively mischievous. Hence, though some of the greatest metaphysicians, such as Plotinus and Spinoza, and to a certain extent Hegel, have been personally mystics, their philosophical method has invariably been scientific and rationalistic. At the same time, it is probably true that, apart from the mystic’s need for the satisfaction of emotion by the contemplation of the eternal and abiding, the intellect would be prone to exercise itself in less arid and more attractive fields than those of abstract Metaphysics. The philosopher seeks, in the end, the same goal as the mystic; his peculiarity is that he is so constituted as to reach his goal only by the route of intellectual speculation.
§ 9. We have compared Metaphysics more than once with Logic in respect of the universality of its scope and the analytical character of its methods. It remains briefly to indicate the difference between the two sciences. There is, indeed, a theory, famous in the history of Philosophy, and not even yet quite obsolete, according to which no distinction can be drawn. Hegel held that the successive steps by which the human mind gradually passes from less adequate to more adequate, and ultimately to a fully adequate, conception of the nature of reality necessarily correspond, step for step, with the stages of a process by which the reality itself is manifested with ever-increasing adequacy in an ascending order of phenomena. Hence in his system the discussion of the general characteristics of reality and the general forms of inference constitutes a single department of Philosophy under the name of Logic. Our motive in dissenting from this view cannot be made fully intelligible at the present stage of our inquiry, but we may at least follow Lotze in giving a preliminary reason for the separation of the two sciences. Logic is clearly in a sense a more general inquiry than Metaphysics. For in Logic we are concerned with the universal conditions under which thinking, or, to speak more accurately, inference, is possible. Now these conditions may be fulfilled by a combination of propositions which are materially false. The same relations which give rise to an inference materially true from true premisses may yield a false inference where the premisses are materially false. Valid reasoning thus does not always lead to true conclusions. Hence we may say that, whereas Metaphysics deals exclusively with the characteristics of reality, Logic deals with the characteristics of the validly inferrible, whether real or unreal. The distinction thus established, however, though real as far as it goes, is not necessarily absolute. For it may very well be that in the end the conditions upon which the possibility of inference depends are identical with or consequent upon the structure of reality. Even the fact that, under certain conditions, we can imagine an unreal state of things and then proceed to reason validly as to the results which would follow if this imaginary state were actual, may itself be a consequence of the actual nature of things. And, as a matter of fact, logicians have always found it impossible to inquire very deeply into the foundations and first principles of their own science without being led to face fundamental issues of Metaphysics. The distinction between the two studies must thus, according to the well-known simile of Bacon, be compared rather with a vein in a continuous block of marble than with an actual line of cleavage. Still it is at least so far effectual, that while many metaphysical questions have no direct bearing on Logic, the details of the theory of evidence are likewise best studied as an independent branch of knowledge.
§ 10. In recent years considerable prominence has been attained by a branch of study known as Epistemology, or the Theory of Knowledge. The Theory of Knowledge, like Logic, is primarily concerned with the question of the conditions upon which the validity of our thinking, as a body of knowledge about reality, depends. It differs from ordinary Logic in not inquiring into the details of the various processes of proof, but confining its attention to the most general and ultimate conditions under which valid thinking is possible, and discussing these general principles more thoroughly and systematically than common Logic usually does. Since the conditions under which truth is obtainable depend, in the last resort, on the character of that reality which knowledge apprehends, it is clear that the problems of the Theory of Knowledge, so far as they do not come under the scope of ordinary Logic (the theory of the estimation of evidence), are metaphysical in their nature. As actually treated by the writers who give this name to their discussions, the study appears to consist of a mixture of Metaphysics and Logic, the metaphysical element predominating. There is perhaps no serious harm in our giving, if we choose, the name Epistemology or Theory of Knowledge to our discussions of ultimate principles, but the older title Metaphysics seems on the whole preferable for two reasons. The discussion of the implications of knowledge is only one part of the metaphysician’s task. The truly real is not only the knowable, it is also that which, if we can obtain it, realises our aspirations and satisfies our emotions. Hence the theory of the real must deal with the ultimate implications of practical conduct and æsthetic feeling as well as those of knowledge. The Good and the Beautiful, no less than the True, are the objects of our study.
Again, if the name Theory of Knowledge is understood, as it sometimes has been, to suggest that it is possible to study the nature and capabilities of the knowing faculty apart from the study of the contents of knowledge, it becomes a source of positive and dangerous mistake. The capabilities and limitations of the knowing faculty can only be ascertained by inquiring into the truth of its knowledge, regarded as an apprehension of reality; there is no possible way of severing the faculty, as it were, by abstraction from the results of its exercise, and examining its structure, as we might that of a mechanical appliance, before investigating the value of its achievements. The instrument can only be studied in its work, and we have to judge of its possibilities by the nature of its products. It is therefore advisable to indicate, by our choice of a name for our subject, that the theory of Knowing is necessarily also a theory of Being.