[§ 1.] The traditional sub-division of Metaphysics into Ontology, Cosmology, Rational Psychology, common to all the great modern constructive systems. [§ 2.] Precise sense in which we adopt these divisions for the purposes of our own treatment of the subject. [§ 3.] Relation of Cosmology and Rational Psychology to the empirical sciences.
§ 1. English philosophers, who have usually been imbued with a wholesome distrust of deliberate system-making, have commonly paid comparatively little attention to the question of the number and character of the sub-divisions of metaphysical philosophy. They have been content to raise the questions which interested them in the order of their occurrence to their own minds, and have gladly left it to the systematic historians of Philosophy, who have rarely been Englishmen, to discuss the proper arrangement of the parts of the subject. Continental thinkers, who are naturally more prone to conscious systematisation, have bestowed more thought on the problem of method and order, with the result that each great independent philosopher has tended to make his own special arrangement of the parts of his subject. The different arrangements, however, seem all to agree in conforming to a general type, which was most clearly exhibited by the otherwise rather arid Wolffian dogmatism of the eighteenth century. All the constructive systems (those, e.g., of Hegel, Herbart, Lotze,) feel the necessity of giving the first place to a general discussion of the most universal characteristics which we find ourselves constrained to ascribe in thought to any reality which is to be an intelligible and coherent system and not a mere chaos. This division of the subject is commonly known by the title it bears alike in the Wolffian Metaphysic and the systems of Herbart and Lotze, as Ontology,[[28]] or the general doctrine of Being; with Hegel it constitutes, as a whole, the contents of the science of Logic, as distinguished from the other two great departments of speculative thought, the Philosophies of Nature and Mind; and its most formal and general parts, again, compose, within the Hegelian Logic itself, the special first section entitled “Doctrine of Being.”
Further, every system of metaphysical philosophy is bound to deal with more special problems, which readily fall into two principal classes. It has to consider the meaning and validity of the most universal conceptions of which we seek to understand the nature of the individual objects which make up the experienced physical world, “extension,” “succession,” “space,” “time,” “number,” “magnitude,” “motion,” “change,” “quality,” and the more complex categories of “matter,” “force,” “causality,” “interaction,” “thinghood,” and so forth. Again, Metaphysics has to deal with the meaning and validity of the universal predicates by which we seek to interpret the nature of the experiencing mind itself, and its relation both to other minds and to the objects of the physical world, “the soul,” “the self,” “the subject,” “self-consciousness,” “ethical purpose,” and so forth. Hence it has been customary to recognise a second and third part of Metaphysics, dealing respectively with the most general characteristics of external Nature and of conscious Mind. These sections of the subject are commonly known as Cosmology and Rational Psychology. In Hegel’s system they appear in a double form: in their most abstract generality they constitute the “Doctrine of Essence,” and the “Doctrine of the Notion” in the Hegelian Logic; in their more concrete detail they form the second and third parts of his complete system or “Encyclopædia” of the philosophical sciences, the previously mentioned Philosophies of Nature and Mind.
In the pre-Kantian eighteenth century it was not unusual to add yet a fourth division to Metaphysics, Rational Theology, the doctrine of the existence and attributes of God, so far as they can be deduced from general philosophical principles apart from the appeal to specific revelation. Kant’s onslaught on the whole Wolffian scheme in the “Dialectic of Pure Reason,” while profoundly modifying for the future the view taken by metaphysicians of Cosmology and Rational Psychology, proved annihilating so far as eighteenth-century Deism and its philosophical offspring, Rational Theology, were concerned, and that sub-division may fairly be said to have disappeared from subsequent philosophical systems.[[29]]
§ 2. There are good and obvious reasons why we should adhere, in the form of our inquiry, to the main outlines of this traditional scheme. It is true that it is largely a question of simple convenience what order we adopt in a systematic metaphysical investigation. A genuinely philosophical survey of the general character of knowledge and experience would exhibit so complete a systematic unity, that you might start from any point in it and reach the same results, much as you may go round a circle equally well from any point of the periphery.[periphery.] But for the beginner, at any rate, it is advantageous to start with the general question what we mean by Being or Reality, and what character is to be ascribed to the whole of Being as such, before attacking the problem of the particular kind of Being which belongs to the various “realities” of common life and the special sciences. Thus we have to discuss in the first part of our programme such questions as the relation of Being in general to experience, the sense in which Being may be said to be inseparable from, and yet again to transcend, experience; the problem of the existence of different kinds or degrees of Being; the question whether Being is ultimately one or many; the relation between Real Being and its appearances. All these problems correspond with reasonable closeness to the contents of what was traditionally known as Ontology.
It is only when we have reached some definite conclusion on these most fundamental questions that we shall be in a position to deal with the more special problems suggested by the various departments of science and common life; hence we shall do well to acquiesce in the arrangement by which Ontology was made to precede the other divisions of the subject. Again, in dealing with the more complex special problems of Metaphysics, it is natural to recognise a distinction corresponding to the separation of Cosmology from Rational Psychology. Common language shows that for most of the purposes of human thought and action the contents of the world of experience tend to fall into the two groups of mere things and things which are sentient and purposive—Physical Nature on the one hand, and Minds or Spirits on the other.[other.] We must, of course, be careful not to confuse this division of the objects of experience with the distinction between an experienced object as such and the subject of experience. We are to start, in our critical investigation, not with the artificial point of view of Psychology, which sets the “subject” of presentations over-against the presentations considered as conveying information about “objects of knowledge,” but with the standpoint of practical life, in which the individual agent is opposed to an environment itself consisting largely of similar individual agents. It is not “Nature” on the one side and a “perceiving mind” on the other, but an environment composed partly of physical things, partly of other human and animal minds, that furnishes the antithesis on which the distinction of Cosmology from Rational Psychology is founded. There is no confusion against which we shall need to be more on our guard than this fallacious identification of Mind or Spirit with the abstract subject of psychological states, and of the “environment” of the individual with Physical Nature. Of course, it is true that we necessarily interpret the inner life of other minds in terms of our own incommunicably individual experience, but it is equally true that our own direct experience of ourselves is throughout determined by interaction with other agents of the same type as ourselves. It is a pure delusion to suppose that we begin by finding ourselves in a world of mere physical things to some of which we afterwards come by an after-thought, based on “analogy,” to ascribe “consciousness” akin to our own. Hence, to avoid possible misunderstandings, it would be better to drop the traditional appellations “Cosmology” and “Rational Psychology,” and to call the divisions of applied Metaphysics, as Hegel does, the Philosophy of Nature and of Spirit or Mind respectively.[[30]]
In recognising this sub-division of applied Metaphysics into two sections, dealing respectively with Physical Nature and with Mind or Spirit, we do not mean to suggest that there is an absolute disparity between these two classes of things. It is, of course, a matter for philosophical criticism itself to decide whether this difference may not in the end turn out to be merely apparent. This will clearly be the case if either minds can be shown, as the materialist holds, to be simply a peculiar class of highly complex physical things, or physical things to be, as the idealist contends, really minds of an unfamiliar and non-human type. It is sufficient for us that the difference, whether ultimate or not, is marked enough to give rise to distinct classes of problems, which have to be treated separately and on their own merits. We may feel convinced on general philosophical grounds that minds and physical things are ultimately existences of the same general type, whether we conceive that type after the fashion of the materialist or of the idealist, but this conviction does not in the least affect the fact that the special metaphysical problems suggested by our experience of physical things are largely different from those which are forced on us by our interest in the minds of our fellows. In the one connection we have, for instance, to discuss the questions connected with such categories as those of uniform spatial extension, uniform obedience to general law, the constitution of a whole which is an aggregate of parts; in the other, those connected with the meaning and value of ethical, artistic, and religious aspiration, the concept of moral freedom, the nature of personal identity. Even the categories which seem at first sight most readily applicable both to physical things and to minds, such as those of quality and number, lead to special difficulties in the two contrasted cases. This consideration seems to justify us in separating the metaphysics of Mind from the metaphysics of Nature, and the superior difficulty of many of the problems which belong to the former is a further reason for following the traditional order of the two sub-divisions, and placing Rational Psychology after Cosmology. In so far as the problems of Rational Theology can be separated from those of general Ontology, the proper place for them seems to be that section of Rational Psychology which deals with the meaning and worth of our religious experiences.
§ 3. It remains, in concluding the present chapter, to utter a word of caution as to the relation between the two divisions of applied Metaphysics and the body of the empirical sciences. It is perhaps hardly necessary to warn the student that Rational Cosmology and Psychology would become worse than useless if conceived of as furnishing in any sense a substitute for the experimental study of the physical, psychological, and social sciences. They are essentially departments of Metaphysics, and for that very reason are incapable of adding a single fact to the sum of our knowledge of ascertained fact. No doubt the discredit into which Metaphysics—except in the form of tacit and unconscious assumption—has fallen among students of positive science, is largely due to the unfortunate presumption with which Schelling, and to a less degree Hegel, attempted to put metaphysical discussion in the place of the experimental investigation of the facts of nature and of mind. At the present day this mistake is less likely to be committed; the danger is rather that applied Metaphysics may be declared purely valueless because it is incapable of adding to our store of facts. The truth is, that it has a real value, but a value of a different kind from that which has sometimes been ascribed to it. It is concerned not with the accumulation of facts, but with the interpretation of previously ascertained facts, looked at broadly and as a whole. When the facts of physical Nature and of Mind and the special laws of their connection have been discovered and systematised by the most adequate methods of experiment, observation, and mathematical calculation at our disposal, the question still remains, how we are to conceive of the whole realm of such facts consistently with the general conditions of logical and coherent thought. If we choose to define positive science as the systematic establishment of the special laws of connection between facts, we may say that over and above the scientific problem of the systematisation of facts there is the further philosophical problem of their interpretation. This latter problem does not cease to be legitimate because it has been illegitimately confounded by certain thinkers with the former.
Or we may put the case in another way. The whole process of scientific systematisation involves certain assumptions as to the ultimate nature of the facts which are systematised. Thus the very performance of an experiment for the purpose of verifying a suggested hypothesis involves the assumption that the facts with which the hypothesis is concerned conform to general laws, and that these laws are such as to be capable of formulation by human intelligence. If “nature” is not in some sense “uniform,” the conclusive force of a successful experiment is logically nil. Hence the necessity for an inquiry into the character of the presuppositions involved in scientific procedure, and the amount of justification which can be found for them. For practical purposes, no doubt, the presuppositions of inductive science are sufficiently justified by its actual successes. But the question for us as metaphysicians, as we have already seen, is that not of their usefulness but of their truth.
It may be said that the inquiry ought in any case to be left to the special student of the physical and psychological sciences themselves. This, however, would involve serious neglect of the great principle of division of labour. It is true, of course, that, other things being equal, the better stored the mind of the philosopher with scientific facts, the sounder will be his judgment on the interpretation and implications of the whole body of facts. But, at the same time, the gifts which make a successful experimentalist and investigator of facts are not altogether the same which are required for the philosophical analysis of the implications of facts, nor are both always conjoined in the same man. There is no reason, on the one hand, why the able experimenter should be compelled to desist from the discovery of facts of nature until he can solve the philosophical problems presented by the very existence of a world of physical facts, nor, on the other, why the thinker endowed by nature with powers of philosophical analysis should be forbidden to exercise them until he has mastered all the facts which are known by the specialists. What the philosopher needs to know, as the starting-point for his investigation, is not the specialist’s facts as such, but the general principles which the specialist uses for their discovery and correlation. His study is a “science of sciences,” not in the sense that it is a sort of universal encyclopædia of instructive and entertaining knowledge, but in the more modest sense of being a systematised reflection upon the concepts and methods with which the sciences, and the less methodical thought of everyday practical life work, and an attempt to try them by the standard of ultimate coherence and intelligibility.