Or common accidents may be such that they are sometimes present in their substances, and sometimes absent-_separable_ accidents. These are by far the most numerous cla.s.s of accidents: thinking, willing, talking, and actions generally; health or illness; virtues, vices, acquired habits; rest or motion, temperature, colour, form, location, etc.
(_b_) The next important division of accidents is that into mere _extrinsic denominations_ and intrinsic accidents; the latter being subdivided into _modal_ and _absolute_ accidents, respectively.
An _absolute_ accident is one which not merely affects its substance intrinsically, giving the latter an actual determination or mode of being, of some sort or other, but which has moreover some ent.i.ty or reality proper to itself whereby it thus affects the substance, an ent.i.ty really distinct from the essence of the substance thus determined by it. Such, for instance, are all vital activities of living things;(257) knowledge, and other acquired habits; quant.i.ty, the fundamental accident whereby corporeal substances are all capable of existing extended in s.p.a.ce; and such sensible qualities and energies of matter as heat, colour, mechanical force, electrical energy, etc. Such, too, according to many, are intellect, will, and sense faculties in man.
There are, however, other intrinsic determinations of substance, other modifications of the latter, which do not seem to involve any new or additional reality in the substance, over and above the modification itself. Such, for instance, are motion, rest, external form or figure, in bodies. These are called _modal_ accidents. They often affect not the substance itself immediately, but some absolute accident of the latter, and are hence called "accidental modes". Those enumerated are obviously modes of the quant.i.ty of bodies. Now the appearance or disappearance of such an accident in a substance undoubtedly involves a real change in the latter, and not merely in our thought; when a body moves, or comes to rest, or alters its form, there is a change in the reality as well as in our thought; and in this sense these accidents are real and intrinsic to their substances. Yet, though we cannot say that motion, rest, shape, etc., are really identical with the body and only mentally distinct aspects of it, at the same time neither can we say that by their appearance or disappearance the body gains or loses any reality other than an accidental determination of itself; whereas it does gain something more than this when it is heated, or electrified, or increased in quant.i.ty; just as a man who acquires knowledge, or virtue, is not only really modified, but is modified by real ent.i.ties which he has acquired, not having actually possessed them before.
Finally, there are accidents which do not affect the substance intrinsically at all, which do not determine any real change in it, but merely give it an extrinsic denomination in relation to something outside it (60). Thus, while the _quality_ of heat is an absolute accident in a body, the _action_ whereby the latter heats neighbouring bodies is no new reality in the body itself, and produces no real change in the latter, but only gives it the extrinsic denomination of _heating_ in reference to these other bodies in which the effect really takes place. Similarly the _location_ of any corporeal substance in _s.p.a.ce_ or in _time_ relatively to others in the s.p.a.ce or time series-its _external_ place (_ubi_) or time (_quando_), as they are called-or the relative position of its parts (_situs_) in the place occupied by it: these do not intrinsically determine it or confer upon it any intrinsic modification of its substance. Not, indeed, that they are mere _entia rationis_, mere logical fictions of our thought. They are realities, but not realities which affect the substances denominated from them; they are accidental modes of other substances, or of the absolute accidents of other substances.
Finally, the accident which we call a "_real_ relation" presupposes in its subject some absolute accident such as quant.i.ty or quality, or some real and intrinsic change determining these, or affecting the substance itself; but whether relation is itself a reality over and above such foundation, is a disputed question.
From these cla.s.sifications of accidents it will be at once apparent that the general notion of accident, as a dependent mode of being, superadded to the essence of a substance and in some way determining the latter, is realized in widely different and merely a.n.a.logical ways in the different ultimate cla.s.ses of accidents.
67. REAL EXISTENCE OF ACCIDENTS. NATURE OF THE DISTINCTION BETWEEN ACCIDENTS AND SUBSTANCE.-It would be superfluous to prove the general proposition that accidents really exist. In establishing the real existence of substances we have seen that the real existence of some accidents at least has never been seriously denied. These are often called nowadays _phenomena_; and philosophers who have denied or doubted the real existence of substances have been called "phenomenists" simply because they have admitted the real existence only of these phenomena; though, if they were as logical as Hume they might have seen with him that such denial, so far from abolishing substance, could only lead to the substantializing of accidents (63).
But while undoubtedly there are realities which "exist in themselves,"
such as individual men, animals and plants, there is no reason for attributing this same mode of existence to ent.i.ties such as the thoughts, volitions, emotions, virtues or vices, of the individual man; or the instinct, hunger, or illness of the dog; or the colour, perfume, or form of the rose. The concrete individual man, or dog, or rose, reveals itself to our minds as a substantial ent.i.ty, affected with these various accidental ent.i.ties which are really distinct from the substantial ent.i.ty itself and from one another. Nay, in most of the instances just cited, they are physically separable from the substantial ent.i.ty in which they inhere; not of course in the sense that they could actually exist without it, but in the sense that it can and does continue to exist actually without them (38); for it continues to exist while they come and go, appear and disappear.(258) Of course the _concrete individual_ man, or dog, or rose, does not continue to _exist actually unchanged_, and _totally_ identical with itself throughout the change of accidents (64), for the accidents are part of the concrete individual reality; nay, even the substance itself of the concrete individual does not remain totally unaffected by the change of the accidents; because if they _really_ affect it, as they do, their change cannot leave it totally unaffected; substance is not at all a changeless, concrete core, surrounded by an ever-changing rind or vesture of accidents; or a dark, hidden, immutable and inscrutable background of a panorama of phenomena (64). But though it is beyond all doubt really affected by the change of its accidents, it is also beyond all doubt independent of them in regard to the essential mode of its being, in as much as it exists and continues to exist in itself throughout all fluctuation of its accidents; while these on the other hand have only that essentially dependent mode of being whereby they are actual only by affecting and determining some subject in which they inhere and which supports their actuality.
The existence, therefore, of some accidents, which are not only really distinct but even physically separable from their substances, cannot reasonably be called into question. To deny the existence of such accidents, or, what comes to the same thing, their real distinction from substance, is to take up some one of these three equally untenable positions: that all the changes which take place within and around us are substantial changes; or, that there is no such thing as real change, all change being a mental illusion; or, that contradictory states can be affirmed of the same reality.(259)
But the nature of the real distinction between accidents and substance is not in all cases so easy to determine. Nor can we discuss the question here in reference to each _summum genus_ of accident separately. Deferring to the chapter on _Relation_ the question of the distinction of this particular accident from substance and the other categories, we may confine our attention here to the distinction between substance and the three cla.s.ses of accidents we have called _extrinsic denominations_, _modal_ accidents, and _absolute_ accidents respectively. "There are accidents," writes Kleutgen,(260) "which place nothing and change nothing in the subject itself, but are ascribed to it by reason of some extrinsic thing; others, again, produce indeed in the subject itself some new mode of being, but without their existing in it as a new reality, distinct from its reality; others, finally, are themselves a new reality, and have thus a being which is proper to themselves, though this being is of course dependent on the substance. These latter alone can be _really_ distinct from the substance, in the full sense in which a real distinction is that between thing and thing. Now Cartesian philosophers have denied that there are any such accidents as those of the latter cla.s.s; rejecting the division of accidents into absolute and modal, they teach that all accidents are mere _modifications_ or determinations of substance, that they consist solely of various locations and combinations of the ultimate parts of a substance, or relations of the latter to other substances."
Now all _extrinsic denominations_ of a substance do seem on a.n.a.lysis ultimately to resolve themselves partly into relations of the latter to other substances, and partly into modal or absolute accidents of other substances. Hence we may confine our attention here to the distinction between these two cla.s.ses of accident and their connatural substances.
And, approaching this question, it will be well for us to bear two things in mind. In the first place, our definitions both of substance and of accident are abstract and generic or universal.
But the abstract and universal does not exist _as such_. The concrete, individual, actually existing substance is never _merely_ "a being that naturally exists in itself," nor is the accident of such a substance _merely_ a verification of its definition as "a being that naturally inheres in something else".
In every case what really and actually exists is _the individual_, a being concreted of substance and accidents, a being which is ever and always a _real unity_, composite no doubt, but really one; and this no matter what sort of distinction we hold to obtain between the substance and its accidents. This is important; its significance will be better appreciated according as we examine the distinctions in question. Secondly, as scholastics understand a real distinction, this can obtain not merely between different "persons" or "things" which are separate from one another in time or s.p.a.ce, but also between different const.i.tutive principles of any one single concrete, composite, individual being (38). We have seen that they are not agreed as to whether the essence and the existence of any actual creature are really distinct or not (24).
And it may help us to clear up our notion of "accident" if we advert here to their discussion of the question whether or not an accident ought to be regarded as having an existence of its own, an existence proper to itself.
Those who think that the distinction between essence and existence in created things is a real distinction, hold that accidents as such have no existence of their own, that they are actualized by the existence of the substance, or rather of the concrete, composite individual; that since the latter is a real unity-not a mere artificial aggregation of ent.i.ties, but a being naturally one-it can have only one existence: _Impossibile est quod unius rei non sit unum esse_;(261) that by this one existence the concrete, composite essence of the substance, as affected and determined by its accidents, is actualized. They contend that if each of the principles, whether substantial or accidental, of a concrete individual being had its own existence, their union, no matter how intimate, could not form a natural unitary being, an individual, but only an aggregate of such beings. It is neither the matter, nor the form, nor the corporeal substance apart from its accidents, that exists: it is the substance completely determined by all its accidents and modes that is the proper subject of existence.(262) It alone is actualized, and that by _one_ existence, which is the "ultimate actuality" of the concrete, composite, individual essence: _esse est ultimus actus_.
Hence it is too, they urge, that an accident should be conceived not properly as "a being," but only as that whereby a being is such or such: Accidens non est ens, sed _ens entis_. But it cannot be so conceived if we attribute to it an existence of its own; for then it would be "a being" in the full and proper sense of the word.
This is the view of St. Thomas, and of Thomists generally. The arguments in support of it are serious, but not convincing. And the same may be said of the reasons adduced for the opposite view: that existence not being really distinct from essence, accidents in so far as they can be said to have an essence of their own have likewise an existence of their own.
Supporters of this view not only admit but maintain that the ent.i.ty of a real, existing accident is a "diminished" ent.i.ty, inasmuch as it is dependent in a sense in which a really existing substance is not dependent. They simply deny the Thomist a.s.sertion that substantial and accidental principles cannot combine to form a real and natural unit, an individual being, if each be accorded an existence appropriate and proportionate to its partial essence; nor indeed can Thomists _prove_ this a.s.sertion. Moreover, if existence be not _really_ distinct from essence, there is no more inconvenience in the claim that partial existences can combine to form one complete existence, _unum esse_, than in the Thomist claim that partial essences, such as substantial and accidental const.i.tutive principles, can combine to form one complete essence, one individual subject of existence. Then, furthermore, it is urged that the substance exists prior _in time_ to some of its accidents; that it is prior _in nature_ to its properties, which are understood to _proceed_ or _flow_ from it; and that therefore its existence cannot be theirs, any more than its essence can be theirs. Finally, it is pointed out that since existence is the actuality of essence, the existence which actualizes a substance cannot be identical with that which actualizes an accident. At all events, whether the one existence of the concrete individual substance as determined by its accidents be as it were a simple and indivisible existential act, which actualizes the composite individual subject, as Thomists hold, or whether it be a composite existential act, really identical with the composite individual subject, as in the other view,(263) this concrete existence of the individual is constantly varying with the variation of the accidents of the individual. This is equally true on either view.
Inquiring into the distinction between substance and its intrinsic accidents, whether modal or absolute, we have first to remark that all accidents cannot possibly be reduced to relations; for if relation itself is something _extrinsic_ to the things related, it must at least presuppose a real and _intrinsic_ foundation or basis for itself in the things related. Local motion, for instance, is a change in the spatial relations of a body to other bodies. But it cannot be _merely_ this. For if spatial relations are not mere subjective or mental fabrications, if they are in any intelligible sense _real_, then a change in them must involve a change of _something intrinsic_ to the bodies concerned. Now Descartes, in denying the existence of _absolute_ accidents, in reducing all accidents to _modes_ of substances, understood by modes not any _intrinsic_ determinations of substance, but only extrinsic determinations of the latter. All accidents of _material_ substance were for him mere locations, arrangements, dispositions of its extended parts: extension being its essence. Similarly, all accidents of spiritual substance were for him mere modalities and mutual relations of its "thought" or "consciousness": this latter being for him the essence of spirit. We have here not only the error of identifying or confounding accidents such as thought and extension with their connatural substances, spirit and matter, but also the error of supposing that extrinsic relations and modes of a substance, and changes in these, can be real, without there being in the substances themselves any intrinsic, real, changeable accidents, which would account for the extrinsic relations and their changes. If there are no intrinsic accidents, really affecting and determining substances, and yet really distinct from the latter, then we must admit either that all change is an illusion or else that all change is substantial; and this is the dilemma that really confronts the Cartesian philosophy.
68. MODAL ACCIDENTS AND THE MODAL DISTINCTION.-The real distinction which we claim to exist between a substance and its intrinsic accidents is not the same in all cases: in regard to some accidents, which we have called intrinsic modes of the substance, it is a _minor_ or _modal_ real distinction; in regard to others which we have called absolute accidents, it is a _major_ real distinction (38). Let us first consider the former.
The term _mode_ has a variety of meanings, some very wide, some restricted. When one concept determines or limits another in any way we may call it a mode of the latter. If there is no real distinction between the determining and the determined thought-object, the mode is called a _metaphysical_ mode: as rationality is of animality in man. Again, created things are all "modes" of being; and the various aspects of a creature may be called "modes" of the latter: as "finiteness" is a mode of every created being. We do not use the term in those wide senses in the present context. Here we understand by a mode some positive reality which so affects another and distinct reality as to determine the latter proximately to some definite way of existing or acting, to which the latter is itself indifferent; without, however, adding to the latter any new and proper ent.i.ty other than the said determination.(264) Such modes are called _physical_ modes. And some philosophers maintain that there are not only _accidental_ modes, thus really distinct from the substance, but that there are even some _substantial_ modes really distinct from the essence of the substance which they affect: for instance, that the really distinct const.i.tutive principles of any individual corporeal substance, matter and form, are actually united only in virtue of a substantial mode whereby each is ordained for union with the other; or that _subsistence_, whereby the individual substance is made a subsistent and incommunicable "person" or "thing," is a substantial mode of the individual nature.(265) With these latter we are not concerned here, but only with accidental modes, such as external shape or figure, local motion, position, action,(266) etc. Now when a substance is affected by such accidents as these it is impossible on the one hand to maintain that they add any new positive ent.i.ty of their own to it; they do not seem to have any reality over and above the determination or modification in which their very presence in the substance consists. And on the other hand it cannot be denied that they express some real predicate which can be affirmed of the substance in virtue of their presence in it, and that independently of our thought; in other words it cannot be maintained that they are mere figments or forms of thought, mere _entia rationis_. If a piece of wax has a certain definite shape, this shape is inseparable from the wax: it is nothing except in the wax, for it cannot exist apart from the wax; but in the wax it is something in some real sense distinct from the wax, inasmuch as the wax would persist even if it disappeared. No doubt it is essential to the wax, as extended in s.p.a.ce, to have some shape or other; but it is indifferent to any particular shape, and hence something distinct from it is required to remove this indifference. This something is the particular shape it actually possesses. The shape, therefore, is an accidental mode of the extension of the wax, a mode which is really distinct, by a minor real distinction, from this extension which is its immediate subject.(267) Hence we conclude that there are accidental modes, or modal accidents, really distinct from the subjects in which they inhere.
69. DISTINCTION BETWEEN SUBSTANCE AND ITS "PROPER" ACCIDENTS. UNITY OF THE CONCRETE BEING.-Turning next to the distinction between absolute accidents and substance, we have seen already that separable absolute accidents such as acquired habits of mind and certain sensible qualities and energies of bodies are really distinct from their subjects. Absolute accidents which are _naturally inseparable_ from their subjects-such as external quant.i.ty or spatial extension or volume is in regard to the corporeal substance-are also really distinct from their subjects; though we cannot know by reason alone whether or how far such accidents are _absolutely separable_ from these subjects: from Christian Revelation we know that extension at least is separable from the substance of a body, and with extension all the other corporeal accidents which inhere immediately in extension.(268)
But a special difficulty arises in regard to the nature of the distinction between a substance and its _proper_ accidents,(269) _i.e._ those which have such an adequate and necessary ground in the essence of the substance that the latter cannot exist without them: accidents which are simultaneous with the substance and proceed necessarily from it, such as the internal quant.i.ty of a corporeal substance, or the intellectual and appet.i.tive powers or faculties of a spiritual substance. The medieval scholastic philosophers were by no means unanimous as to the nature of this distinction. Their discussion of the question centres mainly around the distinction between the spiritual human soul and its spiritual faculties, intellect and will, and between these faculties themselves. It is instructive-as throwing additional light on what they understood by a real distinction-to find that while Thomists generally have held that the distinction here in question is a real distinction, many other scholastics have held that it is only a virtual distinction, while Scotists have generally taught that it is a formal distinction (35-39).
Kleutgen(270) interprets the formal distinction advocated by Scotus in the present context as really equivalent to the virtual distinction. St.
Bonaventure, after referring to the latter distinction, and to the real distinction propounded by St. Thomas, adopts himself an intermediate view: that the faculties of the soul are indeed really distinct from one another, but nevertheless are not really distinct, as accidental ent.i.ties, from the substance of the soul itself. We see how this can be by considering that the material and formal principles which const.i.tute a corporeal substance, though really distinct from each other, are not really distinct from the substance itself. They are not accidents of the latter but _const.i.tute_ its essence, and so are to be referred _reductive_ to the category of substance. So, by a.n.a.logy, the faculties of the soul, though really distinct from each other, do not belong to any accidental category really distinct from the substance of the soul, but belong _reductive_ to the latter category, not indeed as const.i.tuting, but as flowing immediately and necessarily from, the substance of the soul itself.(271) And, like St. Thomas, he finds the ultimate source and explanation of this multiplicity of faculties and forces _in the finiteness_ of the created substance as such.(272) But St. Thomas went farther than St. Bonaventure, for he taught-as indeed Thomists generally teach, and many who are not Thomists-that the faculties of the human soul are really distinct from one another, not merely as proximate principles of really distinct vital acts, but as accidental ent.i.ties or essences; and that as such they are really distinct from the essence or substance itself of the human soul. The arguments in favour of this view will be given in their proper place in connexion with the category of _Quality_. If they are not demonstrative in their force, they are certainly such that the view for which they make is very highly probable; but we are concerned here to show, in this concluding section, that the recognition of a real distinction in general between substance and its accidents does not in any way compromise the real unity of the concrete individual being. It has been widely accused of doing so by philosophers who try to discredit this view without fully understanding it. This characteristically modern att.i.tude is ill.u.s.trated by the persistent attempts that have been made in recent times to throw ridicule on what they describe as the "faculty psychology".(273)
The source of this groundless charge lies partly in the mistaken conception of accident and substance as concrete ent.i.ties superadded the one to the other; partly in the mistaken notion that the union of substance and accidents cannot result in a real unity, that there cannot be more or less perfect grades of real unity (27); and partly in the false a.s.sumption that real distinction always implies mutual separability of concrete ent.i.ties. Of these errors we need only refer to that concerning unity.
Modern philosophers not uncommonly conceive the union of substance and accidents as being necessarily a mere _mechanical_ union or aggregation, and oppose it to "organic" unity which they regard as a real unity involving the richness of an energetic, "living" multiplicity. This involves a misrepresentation of the traditional scholastic view. The union of substance and accident is not a mechanical union. Nothing could be farther from the minds of the scholastic interpreters of Aristotle than the conception of the ultimate principles of the universe of our experience as inert ent.i.ties moved according to purely mechanical laws; or of the individual concrete being as a mere machine, or a mere aggregate of mechanical elements. They recognized even in the individual inorganic substance an internal, unifying, active and directive principle of all the energies and activities of the thing-its substantial form. And if this is all those philosophers mean by the metaphorical transference of the terms "organic unity," "internal living principle of development," etc., to the mineral world, they are so far in accord with the traditional scholastic philosophy;(274) while if they mean that all substances are principles of "vital" energy, or that all reality is one organic unity, in the literal sense of these terms, they are committing themselves either to the palpably false theory of pan-psychism, or to the gratuitous rea.s.sertion of a very old and very crude form of monism.
By "organic" unity we understand the unity of any living organism, a unity which is much more perfect than that of the parts of a machine, or than any natural juxtaposition of material parts in an inorganic whole; for the organs, though distinct in number and in nature from one another, are united by an internal principle to form one living individual, so that if any organ were separated from the living organism it would cease to be an organ.(275) But organic unity is not by any means the most perfect kind of unity conceivable.(276) The living organism exists and develops and attains to the perfection of its being only through a multiplicity of integral parts extended in s.p.a.ce. The spiritual substance is subject to no such dispersion of its being. From its union with the faculties whereby it attains to its natural development, there results a real unity of a higher order than that of any organism.
And nevertheless, even though the unity of the concrete spiritual substance and its faculties be so far higher than a mechanical or even an organic unity, it is not perfect. Even though the faculties of the soul be determinations of its substance, even though they flow from it as actualities demanded by its essence for the normal and natural development of its being, still it is a complete subsisting essence of its kind without them; it possesses its _essential_ perfection without them, so that however intimate be their union with it they can never form one essence with it; it needs them only for the fuller development of its being by acquiring further _intermediate_ perfections and thus attaining to its _final_ perfection (46).
And here we touch on the most fundamental ground of the distinction, in all created things, between their substance and their accidental perfections. Unlike the Necessary, Absolute Being, whose infinite perfection is the eternal actuality of His essence, no creature possesses the actuality of its being _tota simul_, but only by a progressive development whereby it gradually acquires really new intermediate and final perfections, really distinct from, though naturally due to, its essence. Hence, even though some of its accidents-properties such as the powers and faculties we have been discussing-be not really distinct from the essence wherewith they are necessarily connected, this is not true of its acquired habits and dispositions, or of the activities which proceed from these latter as their proximate principles. At the same time the concrete being is, at every moment of its existence and development, a real unity, but a unity which, involving in itself as it does a real multiplicity of distinct principles, must ever fall infinitely short of the perfect type of real unity-that realized only in the Self-Existent, Necessary Being.
CHAPTER IX. NATURE AND PERSON.
70. SOME DIVISIONS OF SUBSTANCES.-In the preceding chapter we discussed the nature of substance and accident in general, and the relation between a substance and its accidents. We must next examine the category of substance more in detail, terminating as it does in the important concept of personality or person. This latter conception is one which must have its origin for all philosophers in the study of the human individual, but which, for scholastic philosophers, is completed and perfected by the light of Christian Revelation. We shall endeavour to show in the first place what can be gathered from the light of reason about the const.i.tution of personality, and also briefly to note how Christian Revelation has increased our insight into the perfections involved in it. As leading up to the concept of person, we must set forth certain divisions or cla.s.sifications of substance: into _first_ and _second_ substances, and into _complete_ and _incomplete_ substances.(277)
(_a_) The specific and generic natures of substantial ent.i.ties do not inhere, like accidents, in individual substances; they const.i.tute the essence of the latter, and hence these _universals_ are called substances.
But the universal as such does not really exist; it is realized only in individuals; in the logical order it pre-supposes the individual as a logical subject of which it is affirmed, a _subjectum attributionis seu praedicationis_. Hence it is called a _second_ substance, while the individual substance is called a _first_ substance. Of course we can predicate attributes of universal substances, and use these as logical subjects, as when we say "_Man_ is mortal". But such propositions have no real meaning, and give us no information about reality, except in so far as we can refer their predicates ("mortal"), through the medium of their universal subjects ("man"), back ultimately to the individual substances (John, James, etc.) which alone are real, and in which alone the universal ("man") has its reality. Hence the individual is, in the logical order, the ultimate and fundamental subject of all our predications. And furthermore, the individual substance cannot be used as a logical predicate of anything underlying itself, while the universal substance can be so used in relation to the individual.
In the ontological order, of course, the universal substance is individualized, and, as individual, it is the subject in which all accidents inhere, their _subjectum inhaesionis_: the _only_ subject of many of them, and the _remote_ or _ultimate_ subject of those of them which inhere _immediately_ in other accidents.
Thus while in the ontological order all substances, whether we think of them as universal or as individual, are the ultimate subjects of inhesion for all real accidents, in the logical order it is only the individual substance that is the ultimate subject of attribution for all logical predicates. Hence it was that the individual substance (t?de t? ??), vindicating for itself more fully the role of subject, was called by Aristotle ??s?a p??t?, _substantia prima_, while he called the universal, specific or generic substance, ??s?a de?te?a, _substantia secunda_.(278) These are, of course, two ways of regarding substance, and not two really distinct species of substance as genus. The distinction between the _membra dividentia_ is logical, not real.
The perfectly intelligible sense in which Aristotle and the scholastics designate the universal a substance, the sense of moderate realism, according to which the universal const.i.tutes, and is identical with, the essence of the individual "person" or "thing," is entirely different from the sense in which many exponents of modern monistic idealism conceive the universal as the substance _par excellence_, the _ens realissimum_, determining, expressing, evolving itself in the individual phenomena of mind and of nature, which would be merely its manifestations.(279)
(_b_) The divisions of substance into spiritual and corporeal, of the latter into inorganic and organic, of these again into vegetative and animal, and finally of animal substances into brute animals and human beings,-offer no special difficulties. All purely natural or rational knowledge of the possibility and nature of purely spiritual substances is based on the a.n.a.logy of our knowledge of the human soul, which, though a spiritual substance, is not a pure spirit, but is naturally allied with matter in its mode of existence. The individual human being offers to human experience the sole example of the sufficiently mysterious conjunction and combination of matter and spirit, of the corporeal mode of being and the spiritual mode of being, to form one composite substance, partly corporeal and partly spiritual.
(_c_) This in turn suggests the division of substances into _simple_ and _composite_. The latter are those which we understand to be const.i.tuted by the natural and substantial union of two really distinct but incomplete substantial principles, a formative, determining, specifying principle, and a material, determinable, indifferent principle: such are all corporeal substances whether inorganic, vegetative, sentient, or rational.
The former, or simple substances, are those which we understand to be const.i.tuted by a sole and single substantial principle which determines and specifies their essence, without the conjunction of any material, determinable principle. We have no direct and immediate experience of any _complete_ created substance of this kind; but each of us has such direct experience of an _incomplete_ simple substance, _viz._ his own soul; while we can infer from our experience the _existence_ of other incomplete simple substances, _viz._ the formative principles of corporeal substances, as also the _possibility_ of such complete simple substances as pure spirits, and the actual _existence_ of the perfectly simple, uncreated substance of the Infinite Being.
(_d_) If there are such things as composite substances, _i.e._ substances const.i.tuted by the substantial union of two really distinct principles, then it follows that while the composite substance itself is _complete_, each of its substantial const.i.tutive principles is _incomplete_. Of course there are many philosophers nowadays who reject as mere mental fictions, as products of mere logical distinctions, and as devoid of objective validity, the notions of _composite_ substance and _incomplete_ substance.
Nor is this to be wondered at when we remember what a variety of groundless and gratuitous notions are current in regard to substance itself (64). But understanding substance in the traditional sense already explained (62), there is nothing whatever inconsistent in the notion of a composite substance, or of an incomplete substance,-provided these notions are understood in the sense to be explained presently. Nay, more, not only are these notions intrinsically possible: we must even hold them to be objectively valid and real, to be truly expressive of the nature of reality, unless we are prepared to hold that there is no such thing as substantial change in the universe, and that man himself is a mere _aggregate_ of material atoms moved according to mechanical laws and inhabited by a conscious soul, or thinking principle, rather than an individual being with one definite substantial nature.
What, then, are we to understand by complete and incomplete substances respectively? A substance is regarded as complete in the fullest sense when it is wanting in no _substantial_ principle without which it would be incapable of _existing_ and discharging _all_ its functions in the actual order as an individual of some definite species. Of course no created substance exists or discharges its functions unless it is endowed with some accidents, _e.g._ with properties, faculties, forces, etc. But there is no question of these here. We are considering only the essential perfections of the substance. Thus, then, any existing individual of any species-a man, a horse, an oak-is a complete substance in this fullest sense. It is complete _in the line of substance_, in _substantial_ perfection, "_in ordine substantialitatis_," inasmuch as it can exist (and does actually exist) without being conjoined or united substantially with any other substance to form a composite substance other than itself. And it is complete _in the line of specific perfection_, "_in ordine speciei_," because not only can it exist without such conjunction with any other substantial principle, but it can discharge _all_ the functions natural to its species, and thus tend towards its _final_ perfection (47) without such conjunction.
But it is conceivable that a substance might be complete in the line of substantial perfections, and thus be capable of _existing_ in the actual order and discharging there _some_ of the functions of its species without conjunction with any other substantial principle, and yet be incapable of discharging _all_ the functions natural to an individual of its species without conjunction with some other substantial principle, in which case it would be _incomplete_ in the line of _specific_ perfection, though complete in everything pertaining to its _substantiality_. We know of one such substance,-the human soul. Being spiritual and immortal, it can exist apart from the body to which it is united by nature, and in this separated condition retain and exercise its spiritual faculties of intellect and will; it is therefore complete as regards the distinctively substantial perfection whereby it is "capable of existing in itself". But being of its nature destined for union with a material principle, const.i.tuting an individual of the human species only by means of such union, and being capable of discharging some of the functions of this species, _viz._ the sentient and vegetative functions, only when so united, it has not _all_ the perfections of its species independently of the body; and it is therefore an incomplete substance in the line of specific perfections, though complete in those essential to its substantiality.
Again, if it be true that just as man is composed of two substantial principles, soul and body, so every living thing is composed of a substantial vital principle and a substantial material principle, and that every inorganic individual thing is likewise composed of two really distinct substantial principles, a formative and a pa.s.sive or material principle; and if, furthermore, it be true that apart from the spiritual principle in man every other vital or formative principle of the composite "things" of our experience is of such a nature that it cannot actually exist except in union with some material principle, and _vice versa_,-then it follows necessarily that all such substantial principles of these complete composite substances are themselves _incomplete_ substances: and incomplete not only in regard to perfections which would make them subsisting individuals of a species, but (unlike the human soul) incomplete even in the line of substantiality itself, inasmuch as no one of them is capable of actually existing at all except in union with its connatural and correlative principle.
Thus we arrive at the notion of substances that are _incomplete_ in the line of specific perfections, or in that of substantial perfections, or even in both lines. An incomplete substance, therefore, is not one which verifies the definition of substance only in part. The incomplete substance _fully_ verifies the definition of a substance.(280) It is conjoined, no doubt, _with another_ to form a complete substance; but it does not exist _in the other_, or in the composite substance, as accidents do. It is _a substantial_ principle of the composite substance, not an _accidental_ determination of the latter, or of the other substantial principle with which it is conjoined. It thus verifies the notion of substance as a mode of being which naturally exists in itself; and united with its correlative substantial principle it discharges the function of supporting all accidental determinations which affect the composite substantial essence. Since, however, it does not exist itself independently as an individual of a species, but only forms the complete individual substance by union with its correlative substantial principle, it may be, and has been, accurately described as not belonging to the category of substance _formally_, but only _referentially_, "_reductive_".
The concepts of composite substance, of complete and incomplete substances, understood as we have just explained them, are therefore perfectly intelligible in themselves. And this is all we are concerned to show in the present context. This is not the place to establish the theses of psychology and cosmology from which they are borrowed. That the human soul is spiritual and immortal; that its union with a really distinct material principle to form the individual human substance or nature is a substantial union; that all living organisms and all inorganic bodies are really composite substances and subject to substantial change: these various theses of scholastic philosophy we here a.s.sume to be true. And if they are true the conception of incomplete substances naturally united to form a complete composite substance is not only intelligible as an hypothesis but is objectively true and valid as a thesis; and thus the notion of an incomplete substance is not only a consistent and legitimate notion, but is also a notion which gives mental expression to an objective reality.