CHAPTER XIII.
THE CONDITIONS OF KNOWLEDGE.
EX PARTE OBJECTI.

§ 237. In this and in the two following chapters I do not propose to give a full or in any way an adequate account of the metaphysics of any realistic philosophy, nor do I propose to discuss in detail the various categories of Being. That is a duty which pertains to the metaphysician as a metaphysician, and not to the epistemologist, who is concerned with metaphysics only in so far as he has to treat of the conditions of human knowledge. My intention here is to give merely a brief outline of the metaphysics of Realism and to deal at length only with those of its characteristics which bear directly upon, and are presupposed by, the realist's theory of knowledge.

A not uncommon method in metaphysics is to take its theses one by one, and to endeavour to show that each is self-evident or that it can be inferred from the data of our experience. I have deliberately chosen another course. Not that I disapprove of the older method, or that I think it impossible to establish individually and yet with some degree of conclusiveness the doctrines of metaphysics; but, first of all, because the detailed discussion which this way of proceeding would involve hardly lies within the province of Epistemology; and, secondly, because I feel that, though to a plain man who, like all men, is born a realist, such a method might prove convincing, it could hardly appear so to one who is already persuaded of the truth of his own philosophic position. Every philosopher is a dogmatist in that he believes and affirms his own philosophy to be better than that of anybody else; and unless you can offer him another philosophy which, taken as a whole, is more systematic, more complete, more self-consistent, more compatible with the facts of introspection and common-sense belief, and finally more capable than his own of satisfying his deepest needs, you can hardly hope to convince him of the probability, not to say the truth, of the theory in which you yourself believe. Now the philosophy of Realism, as it was understood by Aristotle, Aquinas, and is still understood by their modern interpreters, the scholastics, to my mind, presents, when compared with either Absolutism or Pragmatism, the characteristics enumerated above. Accordingly, this is the theory which I propose in brief outline to describe. It is a system and not a patchwork mosaic; and as a system I shall present it, and would beg that from this standpoint it be judged. Tear it to pieces, if you will; but remember that in doing so you destroy its significance and will in consequence be only too liable to under-rate its value.

§ 238. Absolutism without the Absolute would be like a city built in the air, and in the same way Scholasticism without God is a philosophy stripped of the central idea which dominates the whole. The limitations, the imperfections, the corruptibility and the changeful nature of the things which surround us, all point to a something beyond, to a Being who is free from the manifest deficiencies of finite things, to whom they owe their existence and whatever degree of reality they possess, yet of whom they are but the imperfect manifestation. And what we find within points in the same direction. On the one hand, our human souls demand with all the authority of a categorical imperative a satisfaction which shall stop at nothing short of the infinite. But, on the other hand, when we reflect on the impotency of human nature, on its finite knowledge, capability and power, on its weakness and inconstancy, its perversity, its proneness to error and disease, on its ideals which are so often frustrated and never realised in full; when we reflect on these things, I say, we find no guarantee that our needs will ever be satisfied unless indeed it be the obstinate and illogical persistency with which they assert their demands. If, then, these exigencies of our nature are not to be in vain there must be a Being who is capable of satisfying our desires, for their satisfaction cannot come from ourselves or from the finite universe in which we live.

Considerations such as these all point to a supreme and all-powerful Being whose existence and essence are not derived from without, like those of contingent beings, but who exists of Himself, who is what He is because He is, and who cannot, therefore, be other than infinite, since in Him existence and essence are one. Whether the existence of God can be proved from these considerations, it is beyond the scope of my subject to discuss. For the purposes of theory I assume the existence of a supreme and infinite Being, because such an assumption is necessary to explain the universe in which we live, and because without such an assumption our theory of knowledge would not be complete.

§ 239. Granted, then, that there is a Being who exists a se, it follows that all outside Him must exist in dependence upon Him; and of these dependent existents something must now be said. They do not exist of themselves, otherwise they would be identical with God; and they are not infinite, for they could only be infinite if they existed a se. Yet they exist, and their existence can only come from God. They are not self-existents, but essentially dependent beings, brought into existence originally by the mere act of God, and sustained in their existence and activity by the Divine power. It is a common mistake to suppose that the scholastic conceives God and the created universe as beings shut off from one another and independent except for the first act of creation by which they came to be. This is an utter misconception. The universe is regarded by scholastics as dependent upon God almost as completely as it is in the theory of Absolutism. Finite beings are not mere differences of an Absolute Ground, or mere parts of one organic whole. They have their own existence and their own nature, both of which are distinct from His. Yet they resemble and manifest God in their own imperfect way, and, though distinct from Him, never for a moment are they independent. So long as they exist, they depend upon Him for what they are and what they do. Divine conservation and divine concursus or co-operation are necessary from beginning to end. In a sense, we may say with truth that God is the Ground of the universe, so completely does it depend upon Him for all that it is. But that Ground is not a Unity amid difference immanent within a concrete individual whole; for there is not identity, but only a far-off resemblance and a one-sided dependence between created beings and the source from which they ultimately proceed.

§ 240. None the less, in a realist philosophy there is room for the concept of 'unity in difference.' The created universe consists of finite and distinct existents, each having its own nature, each in itself a 'thing'; and every 'thing,' for the realist as for the absolutist, implies a unity in difference. This is of the utmost importance: if it is borne in mind, most of the objections urged against the realist doctrine of 'things' by Mr. Bradley and others disappear. Each thing has its own existence: it exists per se, and so is a substance. Each thing is also a what, it has qualities or accidents, in virtue of which it is different from other things, and in virtue of which also it acts and is acted upon. Between substance and accident, existence and essence, the 'this' and the 'what,' the metaphysician makes what he calls a 'real' distinction. But it must not be supposed that by this he means to affirm that these entities are separate one from another and exist together in the concrete as an aggregate. He means nothing of the kind. Substances are not accidents, and essence is not existence; but, in the concrete, substance and accident, essence and existence, form together an integral and real whole and if either were taken away there would be no concrete 'thing' at all. Accidents are the 'differences' of which substance is the 'ground;' to the substance they give quality, in virtue of which it 'appears.' And both accidents and substances are real; but they do not destroy the unity of the 'thing.'

§ 241. The finite concrete thing always has a certain structure; and this it has even at the level of substance. A substance is not a bare unity, or 'subject' of accidents; nor yet is it merely existence per se. In all corporeal things, whether animate or inanimate, it is itself composite, and its differences are called matter and form. The foundation of this distinction is substantial change. None of the 'things' which we find around us are wholly permanent. They change accidentally and in certain of their outward characteristics; and they may also cease to be and give place to something else. The most obvious instance of a substantial as opposed to an accidental change is that of death, where what was once a living body ceases to be a living body, and becomes, instead, an aggregate of substances, all of them in a rapid state of decomposition. The 'thing' is no longer what it was; its nature has undergone a radical change; or, rather, the thing has given place to some other thing (or things) whose nature and 'substantial form' is essentially different. Even in a substantial change, however, there is an element which remains constant throughout, and that element or principle is metaphysically termed 'matter.' The matter of the living organism and of the corpse which is left behind when death occurs is one and the same. It is the substantial form alone which has disappeared, and has been supplanted by other substantial forms. This will be clearer if we compare more in detail the corpse and the living organism whose place it has taken. In the living organism there is a single principle of life which dominates the whole structure, which has built it up from a single cell, which has made it systematic and organic, which controls all its functions, and which forms with the matter thus organised one real and substantial whole. No part or particle of the matter of a living organism can be said to have properties, mechanical or chemical, which are peculiarly and exclusively its own; nor can the cells of which the organism is largely composed be said to exercise any function in complete independence of the substantial form or principle of life. With the corpse the case is different. The matter of the corpse is the same as that which previously belonged to the living organism, and it still retains for a time its organic structure. But now there is no single principle which animates the whole. Many substantial forms have taken its place. The chemical and mechanical properties which existed only virtually in each part of the living body have now become actual. A substantial change has taken place, and where formally there existed a living whole, we now have merely an aggregate of material bodies whose forms are of a distinctly lower type.

§ 242. In the finite concrete thing we have further structural differences at a level above that of its substance. These are its accidents. Accidents do not exist in separation from or independently of the substance, though in their nature they are distinct. On the contrary, they arise directly from the substance itself. "The actuality of an accidental form," says Aquinas, "is caused by the actuality of the subject, in that the subject, in so far as it is in potentia, is susceptive of the accidental form, but in so far as it is in actu is productive of it."^{1} For this "emanation of essential accidents from the subject takes place by a certain natural resultance."^{2}

The primary characteristics of all corporeal substances are two-fold. They have quantity, and they have quality. The former follows directly from the material principle in the substance; and the latter arises from its formal principle. "The primary accidents resulting from a corporeal substance are quantity and quality, and these two correspond to the two essential principles of the substance, scil., its form and its matter; quantity corresponding to matter, while quality arises from form."^{3}

Quantity is the most imperfect of all accidents, and this is one reason why it is said to pertain to the material rather than to the formal principle in a body. But there are other grounds for this assertion. The size of a thing depends upon the bulk of matter which is united with its substantial form; and this bulk may to some extent vary. An animal, for example, may grow without losing either his individuality or his species. Now growth implies the acquisition of fresh matter from without in the form of food, which, after being 'proximately disposed' by the digestive functions of the animal itself, is assimilated and becomes a part of the living organism, whose 'quantity' is thus increased. That quality arises from the formal principle is also clear; for figure, shape, internal structure, colour, mechanical and chemical properties, sentience, and the power of action, are the characteristics by which one thing is distinguished from another, and pertain, therefore, to that which makes it what it is, i.e., they are the 'natural result' of its substantial form.

§ 243. In general, then, it is the substance of the thing which gives rise to and determines the species of its accidents. Their determination in detail, on the other hand, may be due, in part at least, to external causes. Thus while figure, shape and internal structure depend for their general character upon the essential nature of the thing, they may vary considerably in detail according to circumstances. Figure and shape may be altered by action from without. Structure may be modified gradually or violently by external forces. Colour, again, may vary with environment, and action, too, may turn out in effect to be different from what it was apparently intended to be. In short, every individual thing is both passive and active in regard to other things in its immediate neighbourhood. It acts upon them and they act upon it with the result that both are modified. Action and interaction, therefore, have a good deal to say in respect to the detailed determination of the individual. Prescinding from substantial changes, we may say that in certain respects a thing is permanently actual, while in other respects it is always in potentia. Accidents in general or the specific qualities and properties of a thing, like the substantial form from which they proceed, are essential and cannot change unless the substantial form and the thing itself ceases to be and gives place to something else. But in regard to the particular determination of its accidents, a thing, though actual at any given moment, is in potentia in respect of future modifications. Modifications may take place owing to the action of things outside itself, and similarly the thing itself may produce modifications in other things -- and also in itself if it be a living thing capable of immanent action -- by virtue of its own activities.

§ 244. Thus activity and passivity, as well as actuality (actus) and potentiality (potentia) are characteristic of everything that has a finite nature and in the higher animals and in man these distinctions, like other structural differences, become more marked. The higher animals possess distinct powers or faculties which, in regard to their objects, may be characteristically active or passive. Thus, sensibility is distinctly a potentia passiva, since its function is to receive impressions from without whereas the power of bodily movement is distinctly a potentia activa, since by this means the animal is able to modify its environment. The actualisation of a potentia passiva is due primarily to action ab extra; that of a potentia activa is due to, or rather is, action ab intra. Sensation primarily is an effect produced by some agent outside the living body, or it may be, by the immanent action of the animal itself. Action is primarily the expression of a conative impulse which arises from within and prompts the animal to action in order to effect some change in itself or in what is external to itself.

These statements, however, apply only to the relation of the potentia to its object, and to its mode of actualisation in general. Sensation on its psychical side is an activity, and as with all activities its exercise in any particular form tends to become habitual, and so, according to the general law of all being, to perpetuate itself. Hence even when the object is no longer present, and consequently we have not sensation or perception in the strict sense of those terms, we may have images which are at bottom but faint repetitions of sensations and sensation-complexes. Similarly, action is a particular form of activity and so may become habitual. It is, moreover, closely connected with sensations, perceptions and images, for by them its particular form is largely determined. Habit plays a most important part in all organic life. By it both potentiae passivae and potentiae activae are progressively determined and fixed; and thereby both perception and action are much facilitated. Memory and imagination, too, are accounted for chiefly by habit, and so also are the particular forms of reaction which an animal acquires and which recur immediately a familiar object is perceived.

§ 245. Action is due in part to habit and in part to preceding sensations and images. It is also due in part to conative impulses, as I mentioned above. These impulses arise from animal needs; for every sentient organism has an end or telos, for the attainment of which certain conditions must be fulfilled; and toward the realisation of these conditions it is impelled by a vague though conscious striving. Indeed, every existing being has an end or telos, and in general we may say with Spinoza that its telos is perseverare in esse suo. Everything, whether it be animate or inanimate, strives to realise its own nature and to maintain itself in existence. If it is legitimate to suppose that there is a being so simple that its sole end and function is to vibrate in a particular way and at a certain rate, it will endeavour, as far as in it lies, to go on vibrating at that particular rate and in that particular way, and will strive to overcome all obstacles which hinder the realisation of that end. The significance of the telos in the case of living beings is much greater; and that they strive to realise their nature and to maintain their own form of existence will hardly be denied. This conative tendency is due to the formal principle by which the matter in a living body is organised and built up into a definite structure, a structure which is necessary for the very existence of the animal and which in consequence it endeavours to maintain.

The striving of the formal principle to persevere in its own being, however, is counteracted by the material principle or body which tends to decay; and at first sight these seem to conflict with the general law that every being tends to persevere in esse suo. But this is not really the case. The 'matter' of a living organism formerly belonged to material substances having chemical and other properties, and though these substances as such no longer exist when they have become part of the living organism, their formal principles still exist virtually. Now to exist virtually is not to exist actually nor yet to exist merely in potentia. It constitutes a sort of mean between the two, and implies a tendency to exist. Thus, in these virtually existing formal principles -- call them chemical atoms and molecules if you prefer -- the general law of all being is exemplified, and at the same time by means of this hypothesis several facts may be explained. It explains, for instance, why it is that chemical substances take the place of the living organism immediately after death, not indeed in the original form in which they were first taken up as food, but as re-arranged and reconstituted by the living organism itself. It explains also -- at least, so it seems to me -- many facts connected with disease and decay; for it would appear that the parts of the living organism tend to become independent; and to acquire functions of their own, and so to resist the controlling power and all-pervading influence of the substantial form of the whole. To discuss this point, however, would lead us too far afield. Decay is at any rate a fact which the formal principle of life is ever striving to overcome; whence it is clear that the end of a living organism is to realise its own nature and to perpetuate its own existence.

§ 246. One of the principal ways in which existing things strive to realise their end is by transient action. I refer not merely to those particular actions by which living beings propagate and so perpetuate themselves in their offspring; but to action ad extra of any kind whatsoever. Omne agens agit propter finem; and that finis is to produce in some other thing a characteristic belonging to the thing that acts. For -- if I may quote again an Aristotelian axiom or dictum -- actio sequitur esse; a thing can only act according to its nature. And again, omne agens agit sibi simile; the effect must resemble its cause, for one thing can give to another only what itself has got. Hence, in so far as modification produced in one thing is produced therein by the action of another, there is a similarity or an identity of form between the two. As a matter of fact, however, effects are seldom due to a single cause, but to the co-operation of many causes; and not infrequently the reaction of the relatively passive object may contribute toward that effect. In any given case, therefore, it is difficult to determine what precisely the causes are and to what extent any particular cause is responsible for a given effect. This accounts largely, I think, for the Relativism of many philosophers, especially of those who are scientifically inclined, for in science we know little for certain beyond the fact that, given a certain complexus of phenomena (causes included), another complexus of phenomena will follow. Let us illustrate our principles, therefore, by a comparatively simple example.

A stone is thrown by a small boy and a windowpane broken. The direction and the velocity of the missile were determined by the boy's action, by the direction in which he moved his hand, and by the force which he exerted. The stone passed through the window, and, if its speed was great, the hole in the window will correspond to the shape of the stone. In any case our principle, omne agens agit sibi simile, is illustrated. Motion has produced motion; direction has determined direction. The reaction of the objects in which effects are produced is also illustrated. The air resisted the motion of the stone and its speed, in consequence, was slackened. The window-pane resisted it still more, and soon after it came to a standstill. The stone was thrown against the force of gravitation, and gravitation in the end brought it to the ground. The hole made in the pane of glass, too, will be of the same shape as the stone only provided the latter struck it with a velocity approximating to that of a bullet; otherwise it will be an irregular hole and will be surrounded by cracks due, not to the impact of the stone alone, but in part to the structure of the glass. Thus even a rough analysis of a phenomenon ot this kind is sufficient to show that of the many causes which contributed to produce it, each tended, as far as possible, to reproduce itself, and had our analysis been more precise and quantitatively exact the general principle illustrated would have been still more apparent.

§ 247. One more example may be taken; perhaps not a very good one, but one that is at least familiar and interesting. What is it that causes death? To answer this question we must go back to the doctrine of matter and form. Every corporeal whole consists of matter and form, and before the substantial form can be united with the potentiality of the matter, it is necessary that the latter should be 'proximately disposed' for the reception of the form, and as long as the form exists therein, the matter must retain the disposition or organisation requisite for its existence. Hence, if some hostile agency, violence, or disease of the parasitic type, or, again, a process of decay, destroys the organic structure of a living body, the substantial form which inhabited that body either ceases to be, or, if it has an existence of its own independently of the matter with which it is united, it leaves the body and exists elsewhere. Death, then, in itself, is a negative rather than a positive effect; and considered merely in the negative aspect, it needs no efficient cause. It is not the production, but the cessation of existence. It consists in the destruction of a substantial whole for the existence of which a certain organisation was the material cause and the condition sine qua non. What the so-called 'cause of death' really does, therefore, is to produce in that organism a new form, accidental indeed, yet incompatible with the existence of the principle of life. This form, moreover, remains when life has ceased. Hence it is that the 'cause of death' (i.e., the act which produced the accidental form that occasioned death) may be discovered by a medical examination of the corpse. Poison, for instance, does not act directly upon the formal principle of a living organism, but upon its matter, in which (v.g.) by hardening certain tissues and cells or by causing violent contraction of the muscles, it produces a condition incompatible with the performance of its functions as a living body. Hence, the conditions necessary to life being destroyed, life itself ceases to be, and other substances take the place of the living thing. The formal principles of these substances, however, are not an effect produced by the nominal 'cause of death;' but are due to the fact that, being already virtually in existence, now that the controlling and unifying influence of the living form is gone, they are able to spring into actual existence toward which they were tending all along.

§ 248. The universe, then, as understood by the realist, consists of a world of finite beings, material, organic, sentient, rational; no one of which is merely a phenomenon nor yet merely a substance; but each a concrete individual whole, each a thing, each existing per se and having its own inner structure of substantial ground and accidental differences. And this world of finite beings implies an infinite Being as its ultimate cause or as the condition without which it could neither have begun to be nor yet continue to be. Between God and His creatures there is an intimate connection, for it is to Him that they owe from first to last their existence, their nature, and all their powers. Without His assistance no thing can 'persevere in its being,' and without His concurrence no action can take place. All finite beings are wholly dependent upon the Supreme Being; but they do not proceed from Him as accidents emanate from a substantial ground; nor do they arise within Him as differences within a concrete whole. The relation of God to created existents is unique, and their dependence upon Him cannot be compared except by analogy to any kind of dependence that exists within the finite world. The universe is not an organism, nor yet a living whole. Indeed, if we consider only the finite world of creatures, I should prefer to call it a system, and prescinding from consciousness, to compare it to a huge machine rather than to a living being; for as in a machine so in a finite world, there are parts distinct from one another, yet adjacent and interacting, each having its proper function, and all together forming a systematic whole constructed according to an intelligent plan. Consciousness, however, is a fact, and a fact of supreme importance, without which the universe would be meaningless. Hence the above comparison is far from adequate, as all comparisons must be when one of their terms is the universe itself. Nevertheless, the universe is better described as a systematic, than as an organic, whole. For though all its parts are related, they are real individuals, each having its own existence; and though on account of this relatedness a change in any one part involves a change in some at least of the others, change as such pertains to the individual. In essence change is a transitus de potentia in actum. It presupposes in the individual an already existing potentiality of definite nature which is now realised or determined to 'act' by the action of an efficient cause. And since the universe is a system, rational in its design and its end, all change takes place according to definite and knowable laws. Did we actually know these laws in detail, we should know also the nature of the things upon which they depend, and did we know the nature of things we should know the laws which govern their interactions. But as yet we know neither adequately nor in detail, and until we do, a complete philosophy of nature is impossible.

§ 249. Of the relation of man to the universe in which he lives, nothing has been said as yet, except in so far as man is included under the general heading of living organisms and finite individual wholes and is endowed with all the characteristics which these possess. I have treated the universe from the objective and not from the human point of view; and I have done so deliberately, for in this chapter it is with the object of knowledge and with the general metaphysical principles that underlie the theory of knowledge that we are at present concerned. One or two remarks on the general relation of man to the universe, however, must now be added; and they will, I hope, mitigate somewhat the ire of the humanist at my apparent neglect of the human point of view.

Regarded from the human point of view, everything in the universe is et unum et verum et bonum. It is unum, for every existing being is an individual comprising unity of ground amid structural difference, and as such may be apprehended by man. It is verum (or cognoscibile) for the nature and structure of all existing things is intelligible, and the object manifesting itself to the intellect is, as we shall see, the foundation and ultimate criterion of all truth. And it is bonum (or appetibile); for everything is capable of becoming an object of human desire, and possesses the power of satisfying, directly or indirectly, a human need. These distinctions, however, do not correspond to real differences in the concrete thing; but are relative to man. The truth and goodness of a thing are the thing itself and all that is comprised therein, considered as an object of human knowledge and human desire. Indeed, in a sense all things may be said to exist for man; since he alone of all finite existents can know things as they are and as they are distinguished from one another and from himself; and he alone can rationally appreciate their goodness or value. Other animals can feel the effects which are produced in their sentient organisms by action from without, but not as effects of action from without. And other animals are aware of impulses which prompt them to react in such a way as to satisfy their needs; but of the meaning and significance of such impulses and needs they know nothing. It is only for man that sensation has meaning, and it is he alone who knows the significance of his impulses and his needs; for he alone can reflect and is self-conscious. Knowledge in the strict sense of the term and rational action are characteristics peculiar to man; and for this reason the rest of the world is subordinate to him and, as his knowledge of it advances, steadily becomes more and more subject to his control, more and more subservient to his needs.

§ 250. Our account of the knowable now being complete, we might proceed at once to discuss the knower and the metaphysical theory of the process by which knowledge is obtained, were it not that Mr. Bradley has raised certain objections to the realist's view of the object of knowledge, which must first be disposed of. The objections which concern us most are those which are directed (1) against the doctrine of substance and accident, and (2) against the doctrine of causation.

The doctrine of substance and accident or 'substantive and adjective' Mr. Bradley finds to be a failure; and the first reason he gives is that it seems doubtful what the is can really mean when we say (v.g.) that sugar is white and hard and sweet. "Sugar is obviously not mere whiteness, mere hardness, and mere sweetness; for its reality lies somehow in its unity." But "we can discover no real unity existing outside these qualities, or, again, existing within them."^{4}

What sort of unity is Mr. Bradley looking for here? A unity apparent to the senses? One which can be separated from its qualities and perceived in all its nakedness as a unity? Surely not. Yet, if not, I fail to understand where lies the difficulty. I fear, in fact, that Mr. Bradley is confusing two senses in which the word 'thing' is popularly used. We may say, as he remarks, either that the thing 'sugar' has certain qualities, or that it is white and hard and sweet; but these two forms of predication are not contradictory, for the term 'thing' is not used in the two cases in precisely the same sense. When we say that a 'thing' is so and so, we speak of the concrete thing, regarded as a whole, complete in itself, and embracing a unity in difference. But when we affirm that a 'thing' has qualities, we no longer regard the thing as a concrete whole ; but, analysing it -- mentally, of course -- into a unity of ground or substance on the one hand, and differences of structure, accidents or qualities on the other, we say that this unity which we now call by metonymy a 'thing,' has, or is the ground of, certain differences. This use of the term 'thing' is liable perhaps to lead to misunderstanding, as it has done apparently in Mr. Bradley's case; but, in spite of the ambiguity thereby introduced, it is a use of the term which is not without justification. For clearly 'thing-ness' belongs in the concrete individual to the unity of ground rather than to the qualitative difference, since it is this unity of ground which makes it a thing.

§ 251. Mr. Bradley urges his difficulty, however, by quoting against us the old dilemma: 'If you predicate what is different, you ascribe to the subject what it is not; and if you predicate what is not different, you say nothing at all.'

The reply to this sophistical argument really rests upon what logicians call 'the import of propositions.' -- In fact, we have only to distinguish here the use of the term 'subject,' just as we distinguished above the use of the term 'thing' and the difficulty disappears. For if our 'subject' refers to the substantial unity of the thing, we do not contradict ourselves when we say that it has certain differences any more than Mr. Bradley contradicts himself, when he makes a similar predication of the Absolute. While, if the subject be taken to mean the concrete thing as a whole, again there is no contradiction in affirming that it embraces a certain difference, for the universe in Mr. Bradley's philosophy does the same. In other words, if the subject of our judgment is a substance or a unity of ground, we must use the 'has' form of predication, in which case subject and predicate are not the same, nor are they regarded as the same; whereas if the subject of our sentence be a concrete thing (or, for that matter, a complexus of attributes) then we must use the 'is' type of proposition, in which case we do identify subject and predicate; but we identify them not on the same level, so to speak, but because and in so far as they imply a unity of ground.

§ 252. Many of the objections which Mr. Bradley raises against the notions which are employed in the metaphysics of Realism are, like his objections to the doctrine of substance and accident, based upon a misconception; and objections of this kind it is hardly necessary to discuss since they have been met for the most part, I think, by the exposition already given. Others, again -- indeed the majority -- presuppose his theory of relations which has already been discussed. The difficulties raised in the earlier portion of his chapter on "Causation" are an example of this. Accordingly, I shall pass them over. Toward the end of that chapter, however, an objection of quite a different kind is raised, and this I feel bound to discuss in some detail, not only because it is typical of another type of Mr. Bradley's objections; but also, and more especially, because the doctrine of causation is of vital importance in the realist's theory of knowledge.

The objection, as usual, is thrown into the form of a dilemma. "Causation must be continuous;" for if it were not, it would not be causation, since we should have the cause "enduring unchanged through a certain number of moments, and then suddenly changing." Yet "causation cannot be continuous," for, if it were, the cause would be entirely without duration. "It would never be itself except in the time occupied by a line drawn across the succession."^{5}

§ 253. Now, although Mr. Bradley speaks here of 'continuity,' he seems to me to have a false notion of what a continuum really means, or, at any rate, is not clear as to the difference between a continuum and a series of mathematical points. No succession of points without extension and without duration can under any conditions give rise to a continuum, whether in space or in time. For it is impossible to get extension out of what is unextended, or duration out of a succession of timeless instants, so that a continuum, whatever else it is, cannot be made up of contiguous mathematical points, since in that case it would still be a point. If, however, you ask me to define a continuum, I confess that I am unable to do so. I might say, perhaps, that to be a continuum is to be undivided and yet to have parts outside parts, but this does not help us much, for the parts themselves must have duration and extension, otherwise we shall still be without our continuum. The fact is that the notion of a continuum is for us an ultimate notion, and to define an ultimate notion is clearly impossible. Because the notion is ultimate, however, and cannot be defined, it is not necessarily invalid. For there must be ultimate notions somewhere, and, if these are necessarily invalid, the whole superstructure falls to the ground; knowledge becomes an impossibility, and scepticism our only alternative. Did Mr. Bradley admit the validity of the geometrical concepts of points, lines and surfaces, it might have been possible to prove by a regress the validity of the notion of a continuum, for upon that notion the whole of geometry is based, points, lines and surfaces being nothing else but limits or boundaries which mark off one continuum from another, which is contiguous but qualitatively distinct. Geometrical notions, however, are regarded by Mr. Bradley as fictions, nonentities, useful for some purposes, but none the less fictions.^{6} How a nonentity can be useful, or how a pure fiction can be of service in dealing with the real world, I am unable to understand; but if our notions of surfaces, lines, and points have not a valid foundation in reality, it would be illogical under the circumstances for me to argue from their reality to the reality of the continuum which is presupposed. Consequently, we must adopt another course.

§ 254. Though a continuum cannot be defined, it may be illustrated. And in the first place all consciousness is continuous except for the breaks caused by sleep. Every psychosis has duration and passes gradually and without any actual break of continuity into the next. Secondly, all material things are continuous; they have extension and they last. Strictly speaking, however, material things do not constitute one continuum in the same sense that a spell of consciousness does. For between material things there is a break. They do not pass into one another, but are individual and distinct. Nevertheless, there is still a sense in which we may say that the physical world is a continuum. The extension of the individual in time and in space is limited and so has boundaries, yet the boundaries themselves have no extension, but are, as Mr. Bradley says, limits, in the mathematical sense. While, then, if we regard the world in the concrete as consisting of many individual things, we must say that there are many continua, contiguous, yet discrete if we abstract from thing-hood and qualitative differences, we may say with truth that the spatial, and in like manner the temporal, continuum is one.

§ 255. Having thus cleared up our ideas somewhat in regard to what is meant by a continuum, let us return to Mr. Bradley's destructive criticism of the notion of causation. Is causation continuous? Certainly; for, as Mr. Bradley says, if we were to take a solid slice out of the flow of events, we should find that it contained elements which were in process of change. But does it not follow that a cause is without duration and so cannot be real? This will depend entirely upon what we mean by a cause. If, instead of taking a solid section out of the flow of events, we bisect it by a line, and then by another abstraction divide this line into two aspects one 'before' and the other 'after,' the 'before' aspect being our 'cause' and the ' after ' aspect our ' effect,' certainly neither cause nor effect has duration, and both are equally unreal. But, if we do not make the second of these two abstractions, but, in so far as our line of section marks a difference in the flow of events, are content to call whatever comes before it the cause, and whatever comes after it the effect, then we can assign to both cause and effect as much duration as we please, and this time both will be real. Mr. Bradley's argument is based on a fallacy. He assumes that causation, though continuous, has no duration, or, in other words, that for a finite cause to produce a finite effect no time is required; whereas in fact all causal action is a gradual process which may occupy a considerable period of time. That it should do so is, I grant, an imperfection, but so also is change and everything else in this finite world. And if you choose to say that that which is imperfect is less real than that which is perfect, again I have no objection to raise. On the contrary, I willingly assent; and did we know more adequately than we do what is meant by an all-perfect Being, we might define all finite perfections as the negation or limitation of some one of His; for in some way or other change, time, space imply imperfection and the negation of tota simul. But since we cannot adequately conceive the All-perfect, we must be content to start with a knowledge of finite perfections and to infer what God is from our knowledge of them. And though He alone is fully real, it does not follow that finite perfections are unreal, or our notions of them invalid; still less that they are self-contradictory. To much ignorance I confess; with a doubt I can sympathise; but a contradiction in philosophy is intolerable.

{1} Summa Theologica, p. I, q. 77, a. 6.

{2} Ibid., ad. 3.

{3} Aquinas, in IV. Sent. d. 22, q. I, a. 1.

{4} Appearance and Reality, p. 19.

{5} Appearance and Reality, pp. 60, 61.

{6} loc. cit, p. 61.