JMC : Pre-Scholastic Philosophy / by Albert Stöckl


§ 35.

1. We have already indicated what Aristotle conceives to be the province of Metaphysics, or the First Philosophy. It deals with Real Being as such; it investigates the principles or ultimate causes of Being. The first question which Metaphysics has to answer is this: What are the common principles of all Being. In answering this question, Aristotle first replies indirectly, examining and refuting the opinions of earlier philosophers. He then replies directly, setting forth his own teaching on the subject.

2. With regard to his refutation of other philosophers, we shall here confine ourselves to his arguments against Plato's theory of Ideas. Ideas, in Plato's sense of the word, he says, are not the principles of Being; nay, such Ideas are not admissible at all; and this for the following reasons

(a.) In the first place, the Platonic Theory of Ideas is wholly barren "These ideas arc only a meaningless duplication of sensible objects (a kind of aisthêta aidia, eternal sensibles)," and do not in auywise help to explain the existence of individual objects. They contain only the forms of things, and these must he combined with Matter in order to give the things actual existence. This combination can only be effected through motion; and Ideas are not the moving principles of things. (Met. I. 7, 9; XII. 6; XIII. 5.)

(b.) Ideas are said to represent and to contain the essences of things. Now, it is altogether impossible that the essence of a thing and the thing itself should exist apart from one another. This the more, that such an admission leads to manifest contradiction. For "if an universal idea, v.g., 'animal' exists apart from the 'man' and 'horse' contained under this universal idea, we may ask whether this idea as it is in the latter is numerically one and the same in all, or are there different ideas in the different objects? The first alternative cannot be admitted, for a notion cannot remain numerically one in things that are different, otherwise the generic concept would he simultaneously determined by the specific differences of several species, i.e., by opposite attributes -- an evident contradiction. Nor can the second alternative he accepted, for in this case the genus would be really multiplied in the species, and thereby the unity of the concept would be destroyed -- and it is Plato's aim to maintain the unity of the concept." (Met. VII. 14.)

(c.) "Again, these Ideas, described as distinct from the objects which participate in them, either have nothing in common with these objects beyond the name, or they have a certain community of nature with them. In the first case, they are entirely without effect for the knowledge of the objects in question; in the second, the community of nature supposes participation in a third entity common to both" -- i.e. the Ideas and the corresponding individual objects require a third common prototype, on whsch both shall he modelled; v.g., the individual man and the Idea of man require a "third man" (tritos anthrôpos), Met. I. 9 ; VII. 13. (This argument of the "third man" seems to have become proverbial among the opponents of the Platonic theory.)

(d.) Plato calls the Ideas "prototypes" of the objects of sense, and describes the relation in which the latter stand to them as a "participation." But these are empty words, mere poetical metaphor, which explains nothing, and, besides, entails absurd consequences. For, since one and the same object is frequently included under several different concepts -- v.g., Socrates is included not only under the concept 'man,' but also under the concepts 'animal' and 'biped' -- it follows that for one and the same object we must have several prototypes, and that Ideas are miot prototypes of sensible objects, but are derived from them in the same way as the generic concepts are derived from the species. Met. I. 9; XIII. 5.

(e.) The fact that there is such a thing as scientific knowledge is no argument in favour of this theory; "we may, indeed, conclude from this fact that the universal has a real existence, but not that it has a separate existence. If the latter consequence followed, other consequences would follow which the Platonists would not and could not admit. For example, it would follow that there exist Ideas corresponding to works of art, and even to things which have no substantial being, such as attributes and relations, for we have single concepts of each of these things (to noêma en).{1}

3. From the negative side of Aristotle's teaching we pass to the positive. The principles of all Being, as given by Aristotle, are four: Matter (hule), Form (morphê or eidos), Efficient or Moving Cause (to kinêtikon), and Final Cause or End (to ou heneka). These are the necessary assumptions, the ultimate basis of all Being, and are not themselves derived from anything else; they are, therefore, Principles (archai) of things (Phys. I. c. 6, 2); they are also Causes (aitia), inasmuch as the Existence as well as the Being of things is dependent on them (Met. I. 3; Plays. II. c. 3, 1, seq.). "The earlier Greek philosophers," remarks Aristotle (Met. I. 3, seq.), "investigated only the Material Principles of things; Empedocles and Anaxagoras inquire into the Cause of motion; the Formal Principle has not been clearly indicated by any of the earlier philosophers, the nearest approach to it has been made by the authors of the Theory of Ideas; lastly, the Principle of Final Causes has been understood and recognized by the older philosophers only in a relative, not in an absolute sense."

4. The first of the four principles of Being is Matter. Matter is that which is indeterminate in itself, but capable of determination. As such, it is the substratum of all that comes to be -- that out of which all things are made. Everything that comes into being arises out of a condition the opposite of that on which it enters, and everything that perishes passes into a condition the opposite of that in which it existed. Out of Non-being arises Being; the Existent passes in turn into the Non-existent. This process is impossible unless we suppose an underlying substratum in which the origin and the dissolution of things are accomplished; this substratum is Matter. Matter is not, therefore, a determinate Being; it is merely the indeterminate substratum of all determinate Being.

5. The second principle of Being is Form, a principle in immediate relation with Matter. Matter is the indeterminate but determinable element; Form is the determining element -- i.e. it is a principle, within the object, giving it determinate character. Matter is that out of which a thing is made; Form is that into which it is made. What comes to be comes to be something, and the element by which it comes to be this determinate something is its Form. Form, as conceived by Aristotle, is not merely external shape or conformation, it is an intrinsic principle of Being, by which the inner nature of the object becomes what it is.

6. The union of Matter and Form constitutes the Substance -- the concrete Being of the object. Neither Matter by itself nor Form by itself is, properly speaking, a being; it is only the union of both that can be so designated. Matter and Form united constitute the specific nature, which, being realized in the individual, comes before us as Substance or determinate being. Considering Matter and Form in their relations to the determinate being that results from their union, we are able to fix still more distinctly their relations to one another.

(a.) Matter is naturally destined to receive a Form; hence its tendency towards Form resembles the tendency of the female to the male. This lack of Form in Matter does not mean mere negation; it is the want of something which should be present, it is Privation (sterêsis). Privation (sterêsis) is the peculiar characteristic of Matter considered in itself, apart from Form. Taken thus by itself, it appears to possess merely negative characteristics. There is, however, a positive characteristic involved in the notion before us; namely, its disposition to become determinate by means of a Form; without this disposition the lack of the Form could not be called Privation.

(b.) The privation of Form as applied to Matter can be understood in two senses -- absolutely and relatively. A substance which already possesses definite Form may stand in the relation of Matter to a higher substance, inasmuch as it may receive a higher Form, and thus become a higher substance. In this case, the privation which affects the Matter in question is merely relative, involving only the want of that higher Form to which the Matter can and should attain. We can, however, in thought, separate Matter from any and every Form, and consider it as entirely formless. In this case the privation is absolute. Matter considered as subject to this absolute privation, represented in thought as deprived of all Form, is called "Primal Matter" (hulê prôtê), Materia Prima. This is Matter kat exochên; whenever we speak of Matter without qualification we must be understood to speak of "Primal Matter."

(c.) That Form may be realized in fact, Matter must be presupposed; the actual reality, however, depends upon the union of Form with Matter. In a substance composed of Matter and Form, Matter may thus be regarded as the Potentiality (dunamis), Form as the Actuality (entelecheia). The element which constitutes the possibility of the substance is Matter; the element constituting its actuality is Form. Matter apart from Form, in the order of actual existence, is therefore wholly unthinkable. We must, indeed, suppose a Matter without any Form whatever, as the basis of all existent substances, but, as such, it is itself never actually existent, and can never so exist, for the reason that it is in itself mere potentiality. The predicate of Being can be attributed to it only if we understand it to be in the order of possibility, not in the actual order.

(d.) Form, or entelecheia, is the actuality of things; but we must draw a distinction between entelecheia prôtê and energeia. The entelecheia prôtê is the actuality of the object, the complement or completion of the substance in the order of actual being; the energeia, on the other hand, is its Activity, of which the actual substance is the principle and the source. Form, it will be observed, can be called Entelechy only when understood to be one with the entelecheia prôtê; energeia, on the other hand, is dependent on the Form, for Form is the principle of actuality. Aristotle does not, however, maintain strictly this distinction between the two concepts; he not unfrequently describes Form as energeia.

7. The third principle of Being is Efficient (or Moving) Cause. It is a fact of experience that there is movement in the world about us. Movement supposes a moving cause; without this it is unthinkable. The moving cause, whatever be its nature, cannot be conceived as mere potentiality, it must always be an actual being; for only the actual being can exert an energeia, or, in the present instance, actively produce movement. Every movement, then, supposes an actual cause, an entelechy proper, from which the movement proceeds.

8. With regard to motion itself (kinêsis), the following are the chief points of Aristotle's teaching

(a.) Motion, in general, is the actualization of the possible, he tou dunatou, he dunatou entelecheia (Phys. III. 1). It is, therefore, the transition from the possible to the actual. Wherever a process of transition from possibility to actuality is in progress, we can say of the thing involved in the process that it is in motion.

(b.) There are, however, different kinds of motion. We must distinguish between the motions which suppose a fully constituted, determinate object, and are accomplished in this object, and the motions which affect the existence or non-existence of the object. To the former class belong quantitative, qualitative, and local motions; that is to say, increase and diminution (auxêsis kai phthisis), change or alteration (alloiôsis), and locomotion (phora). To the second class belong origin or generation (genesis) and dissolution or corruption (phthora).{2}

(c.) Quantitative, qualitative, and local motions differ from generation and corruption in this, that they involve only a transition from one condition of the subject to another, whereas in generation and corruption we have a transition from non-existence to existence, or conversely. In generation the terminus a quo is non-existence, the terminus ad quem is existence. In corruption we have the converse process. Matter, however, cannot, as we have already seen, exist without some form or other. Nonexistence, therefore, can apply to the two cases we have been considering only in a relative sense; i.e. the terminus a quo in generation is not absolute non-existence, but only the non-existence of that which is generated. The same, in its measure, holds good with regard to corruption. There is not, then, any absolute origin of things, nor any absolute destruction. Everything that begins to be comes into existence by the corruption of something else, and everything that perishes passes into another being -- "Generatio unius est corruptio alterius, et corruptio unius est generatio alterius."

(d.) The first and most excellent form of motion is locomotion. On this all the others depend. But locomotion introduces two further notions, Space and Time.

(a.) Place (locus, topos) is defined by Aristotle as the first immovable limit of the enclosing body (to tou periechontos peras akinêton prôton, Phys. IV. c. 6. 15, 24) -- a definition which makes an empty place impossible. Enlarging this notion of the topos, and extending it to the great bodies or the universe, we obtain by this means the notion of universal space. The universe, taken as a whole, cannot, it is evident, exist in space (or in a place), for there is no enclosing body by which it could be surrounded. Space exists only within the world; outside it there is no space. Space extends only to the outer limits of the world.

(b.) Time is defined by Aristotle as the measure of motion in order of antecedence and consequence (arithmos kinêseôs kata to proteron kai husteron, Phys. IV. c. 16, 7). The unit of time is the present, and from the motion of this unit time is produced. Time has neither beginning nor end; it is eternal in both directions, for every present supposes a past and a future, and thus no point can be found at which time could arrest its course. Time is measured by uniform movement; to this purpose circular movement is particularly adapted.

9. Lastly, the fourth principle is the End or Final Cause. The End is that to which the motion issuing from the Efficient Cause is directed. Movement without this term to which it is directed is inconceivable; the End must, therefore, be one of the necessary principles of actual Being. It is, indeed, possible that in a given movement a result may ensue which was not intended, which is the effect of some collateral cause attaching to the means employed to attain a certain end -- this is tuchê, chance, casus fortuitus. But this does not in any way prejudice the notion of purpose as belonging to motion; on the contrary, chance, tuchê, necessarily presupposes this notion. The End is always a Good, to be obtained by the motion; the Ratio boni cannot be dissociated from the notion of End.

10. Having laid down these general principles regarding the notion of the Final Cause, we may now proceed to examine the notion in its special applications

(a.) When we apply the notion of End to that movement which we have called generation, we observe at once that the End to which this movement tends and the Form are one and the same thing; in other words, the Form is not only the result, it is also the end or purpose of the generative process. The realization of the Form in Matter is the scope of the process. Thus, the Form is not only the principle of determinateness and actuality in the substance, which consists of Matter and Form, it is further the end or purpose intrinsic to the substance.

(b.) The relation already pointed out between Matter and Form leads us further to observe that, in substances of the kind under consideration, Matter is the irrational element, whereas Form, being the element on which plan or purpose is based, betokens Reason, and is the object of a mental concept. Matter is, therefore, the anagkê, or blind necessity; Form is the end or purpose, the rational element in the thing (logos).

(e.) In the generation of things Form and Final Cause are one; it may also happen that the Moving Cause and the Final Cause become identical. This occurs when the Moving Cause occasions movement, not by physical impulse, but as an object of desire. In this case, the Moving Cause is unquestionably the End towards which the movement excited is directed. The kinêtikon and the ou heneka are, therefore, one and the same.

11. Thus much regarding the principles of Being. On the basis thus established, Aristotle proceeds to construct his theory regarding the World and God. A prominent point in his teaching on the first of these points is his doctrine of the eternity of the world, which he strives to establish by the aid of the foregoing metaphysical principles. In his reasoning he proceeds as follows: --

(a.) Matter cannot have had a beginning. For Matter, as we are aware, is the basis of all things, necessarily antecedent to the origin of all other things. It is the potentiality of everything having actual existence; what comes into being must come from Matter. If we suppose Matter to have itself come into being, we are driven to assume another Matter, which shall be the basis or potentiality out of which it shall arise; in other words, Matter must be supposed to exist before it existed. This is self-contradiction. Matter, then, has not begun to be; that is to say, it is eternal.

(b.) Again, we know Matter cannot exist without Form. If, then, we admit that Matter is eternal, we must admit that Form also is eternal. We cannot, in consequence, allow that Matter was at first shapeless and formless, and has gradually assumed its present form and condition, as Plato thinks; we must, on the contrary, assume that, as regards both Matter and Form, all things have been without beginning; in other words, that the world, as it is, is eternal.

(c.) We are led to the same conclusion when we consider the nature of Motion: --

(1.) If Motion had a beginning, there could have existed previously to this beginning only the possibility of Motion. To account for the beginning of Motion, we must suppose this possibility to have been rendered actual. But this could be effected only by Motion. Motion must, therefore, have existed before its beginning -- an evident contradiction.

(2.) Furthermore, Time, as has been shown, has had no beginning. But Time is inseparably identified with Motion, for it is nothing more than the measure of Motion in the succession of 'before' and 'after.' It follows that, if Time is eternal, Motion is also eternal.

Now, if Motion is eternal, so also is that which is moved. As the thing moved is the world, the world, like Motion, must be without beginning; it also must be eternal.

(d.) The world is thus proved eternal a parte ante. That it is eternal in this sense is proof that it is also eternal a parte post. For, in the first place, Time, as it is without beginning, is also without end; it follows that Motion and the thing moved, both of which the notion of Time supposes, must be without end. In the second place, all corruption is transition from one Form to another, since the corruption of one thing is the generation of another, Matter the while, not being liable to change, as it is wholly incorruptible. This being so, it is impossible that the Forms existent in the world, taken in their totality, should be subject to corruption. Matter cannot exist without Form; the corruption of all existing Forms would, therefore, involve the corruption of Matter -- which has already been shown to be impossible. The world, being one aggregate of things which consist of Matter and Form, is thus shown to be without end; the notion of generation is inapplicable to the world, so also is the notion of corruption.

(e) Generation and corruption take place only within the world. And even here, generation and corruption only affect the individual, they do not reach the species or the genus. Individuals alone come and go; species and genera are eternal. If a species were to perish, then would one determinate Form disappear from the world -- a consequence which is inadmissible, since it has been proved that existing Forms, taken as a whole, are incorruptible. As regards individuals, the succession of generation and dissolution is from eternity like the world itself. Within the world, the process of the rise, origin, and destruction of individuals, has not had a beginning, nor will it have an end.

12. Aristotle further seeks to prove that the world is one -- that there can exist only one world. This he proves from the principle already laid down, that the basis of all plurality in things within any one species is Matter. If there were more worlds than one, each should have Matter peculiar to itself. But Matter, as the substratum of all generation and corruption, is absolutely one; if this were not the case, there would be no one substratum in which the origin and dissolution of things could be effected. There can, then, be only one Matter; and this being so, there cannot be several worlds, with several different material substrata. There is, therefore, only one world, and beyond this no other world is possible.

13. Thirdly, the world is limited or finite. We must distinguish two kinds of infinitude. A thing may be either potentially or actually infinite. It is potentially infinite when it is capable of indefinite increase; actually infinite when it excludes all augmentation, and all capability of increase. Now it is clear that the world cannot be actually infinite, for let us imagine its extent to be as great as we will, it is always possible to suppose it still greater. The world can therefore be only potentially infinite. But what is potentially infinite -- for the reason that its infinitude is only potential -- must always be actually finite, be its actual extension what it may. It follows that the actual world must always be finite or limited. The same holds good of space; for space, as we have already seen, extends only to the outside limit of the world.

14. In his teaching regarding God, Aristotle is guided by the metaphysical principles here set forth. His proofs for the existence of God first claim our attention. These proofs are as follows:

(a) It has been shown that motion is eternal. Now every motion supposes a moving cause. If this cause derives its motion from something else, this something else must in its turn have a moving cause, and so on successively. But the series of moving causes cannot be infinite, for the infinite cannot be traversed, and besides, what is actual is always finite. We must, therefore, assume a Primal Motor, which does not receive motion from anything else, and from which, in the last resort, all motion proceeds. This Prime Motor (prôton kinoun akinêton) is God.

(b) Furthermore, the actual is, of its nature, antecedent to the potential. For the potential supposes a cause which can give it actuality, and this cause must itself be actual, otherwise it could not be productive. Potentiality is, therefore, not conceivable apart from an antecedent actuality. Now, Matter is eternal, but Matter is mere potentiality; we must therefore admit an eternal actuality, an eternal entelechy, which, as such, is antecedent to Matter, and which we name God.

15. It is now easy to determine what are the attributes of God. As to the Being of God, Aristotle teaches:

(a) God is pure actuality, pure entelechy. He excludes all composition of Matter and Form. If the Divine Being were a compound of Matter and Form, it should have had a beginning of existence, and it could begin to exist only by the action of a higher cause moving the Matter to union with the Form. In this supposition God would cease to be the Prime Mover. God is, therefore, pure Form, pure Quiddity, pure Energy.

(b) God is further an absolutely Simple Being, essentially excluding all plurality of parts. For if the Being of God were composed of parts, it would have magnitude. This magnitude would be either finite or infinite. It could not be infinite, for an infinite magnitude actually existent is an impossibility. Nor could it be finite, for in that case the might of God would be finite, and He would be unable to furnish motion through unending time, i.e., keep in motion an eternal world. It follows that the Divine Being excludes all plurality, all parts; it is absolutely simple, and therefore immutable.

(e) Finally, God must be One. For the principle of plurality is Matter -- the basis of individuality within the same species. But Matter is wholly foreign to the Being of God. Hence there can be no question of a plurality of gods. In the same way we may show that to the Divine Being there is no opposite term. For opposition can occur only in the case of two beings having a common Matter, within which opposite Forms exist. To admit that anything could stand in opposition to God would be to admit Matter in the Being of God -- an admission we have seen to be unwarrantable.

16. With reference to the activity of God, we must hold as a primary truth that God, as absolute actuality, is also absolute life. As absolute life, He is all-sufficient in Himself, and possesses in Himself perfect bliss. For His happiness He needs not any external goods; He is Himself the Highest Good, and is therefore happy in Himself. But the further question arises: What are the definite characteristics of this absolute life of God? Aristotle answers:

(a) The life of God is not an operative life. We cannot admit in Him activity of Will, productive of effects external to Himself. If we admitted such an activity of Will in God, we should then be forced to admit that God has need of goods external to Himself, and that He seeks to obtain these goods by the activity in question. This admission is incompatible with the principle that God is absolutely sufficient to Himself.

(b) The life of God is a life of contemplation, and of contemplation only: God lives by thought, and by thought alone. God is reason (nous), and only reason. He is a purely contemplative spirit; and, as such, excludes all volitional action.

(c) But what is the object of this contemplative action? Aristotle's answer to this question is as follows:

(1) The object of the Divine Thought is not anything external to the Divine Being. For the thing known is to this extent superior to the knowing subject, that the latter is dependent on it. If, then, God were to have knowledge of things external to Himself, He would be dependent on these things, and there would exist something superior to God. This conclusion is inadmissible. To which we may add that there are many things apart from God which it is better not to know -- things so base that they are not worthy objects of knowledge.

(2) Hence it follows that the sole object of the knowledge of God is God Himself. God is the only worthy object of the Divine knowledge; it is, therefore, restricted to Him. Man attains his happiness by attaining knowledge of other things; God is made happy only by the knowledge of Himself. In the vision of His own Being, then, consists that contemplation which makes the absolute immanent life of God.

(3) This Divine self-knowledge is not of the same kind as our knowledge of ourselves. In us being and knowledge of the being are different things. In God the knowledge and the thing known are absolutely one and the same. God's self-knowledge is not merely noêsis, it is noêsis noêseôs -- absolute identity of thinking and object thought. (Met. XII. 9.)

17. The relations of God to the world can be deduced from what has here been laid down. Aristotle's doctrine on this point may be summarised as follows:

(a) God is not indwelling (immanent) in the world; He exists above it -- the Absolute Substance, the Absolute Archetype. His relation to the world is that of the general to his army. As Prime Mover he is not at the centre of the world, but without its utmost boundary. For the more rapidly a thing moves the nearer must it be to the Prime Mover. The motion of the heaven of the fixed stars is the most rapid; it follows that this heaven is nearest to God, and since this heaven forms the uttermost limit of the world, God must be beyond this extreme limit. Aristotle, it thus appears, had no knowledge of the omnipresence of God.

(b) God, as the Prime Mover, communicates motion necessarily and eternally. The motion which proceeds immediately from God must, therefore, be necessary and eternally continuous. It must further be one, for on the oneness of the motion which proceeds from God depends the oneness of the world. This motion must be locomotive, for it is only a motion of this sort which can be continuous and one. Not all locomotion, however, has these properties; but only the motion which proceeds indefinitely in a straight line, or motion a circle. The former of these cannot exist, for it supposes an infinite space. There remains only motion in a circle. We thus conclude that the motion proceeding immediately from God is motion in a circle.

(c) Action upon things external to Himself cannot be attributed to God; it follows that He cannot communicate motion to the world by physical impulse. He can excite motion only as an object of desire. He is at once the archetype and the ultimate end, and chief good of all things in the world; He is, consequently, an object of desire to these things, and, as such, He gives the world its motion. God being the supreme good, and the object of desire, standing above all things, all things move towards Him, and by their motion seek to share in His eternity and immortality. According to the different position held by each object in the mundane order, is the mode of its motion towards this end. Hence the differences of motion.

(d) Athough God's relation to the world is that of Prime Mover, yet there cannot be question of a Divine Providence, in the sense that God provides immediately for each and every thing in the world. Such a Providence supposes that God knows all things in the world. But we already have seen that this is not the case; God does not, therefore, exercise a providence over the world. The motion which God communicates to the world assures the existence and the order of the universe, the permanence of the celestial spheres, and of the genera and species of things on the earth. Individuals, as such, are merely transient phenomena, which appear on the stream of time only to sink into it again. They are not subject to any higher guiding providence.

18. His teaching with regard to God is undoubtedly the weakest point in the system of Aristotle. He regards God merely as the Prime Mover of the world, and assigns Him no other relations to the world than those which depend on the motion he communicates. As this motion is necessarily communicated by God, it is clear that Aristotle makes Necessity control all things. He knows nothing of Ideas within the Divine Mind, which are the archetypes of created things; he recognises no Divine Providence which guides the universe, no Divine Will, which, of its free accord, gave origin to the world. Under the stern law of Necessity nature runs its eternal course, and individual things are but products of the necessary evolution of nature, appearing for a moment, and then disappearing again. Motionless, though communicating movement, God is separated from the world. What occurs in the world, takes place without concurrence from Him; He does not even know what is taking place. In his theological notions, Plato is clearly far in advance of Aristotle; his teaching regarding God is nearer the truth than Aristotle's theory of the "Prime Mover."

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{1} It is observable that, in his refutation of the Platonic theory, Aristotle assumes throughout that Plato regarded Ideas as possessed of independent existence, apart from sensible things, and apart also from the Being of God. This assumption being granted, his arguments are conclusive. But this could not be said of them if we assume the right explanation of Plato's theory to be that he regarded Ideas only as conceptions of the Divine mind.

{2} The word kinêsis is sometimes employed by Aristotle (v.g. Phys. III. 1) as equivalent to metabolê (change), since every movement involves a change. He says, however (Phys.V. 1), that, although every kinêsis is a metabolê every metabolê is not, conversely, a kinêsis; for example, such as affects the very existence of the object, i.e. genesis or phthora. Accordingly, genesis and phthora should, properly speaking, be included, not under the notion kinêsis but under the notion metabolê. This has not been noticed above, as Aristotle does not uniformly maintain the distinction.