4 (Or, ‘ There is, in a way, some resemblance between the working of (logical) necessity in mathematics and the necessity involved in things coming into existence hy process of nature. ‘Thus, 1f the ier a hne 1s defined as it is, it is a necessary consequence that the angles of the triangle should be equal to two right angles. On the other hand we cannot prove the truth of the definition from this property of the triangle; though we can say that, if the triangle has not this property, then Bonne new ering to the definition of “straight Ine” exists.’ (The property of the (rectilinear) triangle, demonstrated in Enclid i. 32, follows from (1) the definition of straight line (and of other terms), (2) the “hypo- thesis” that such things as those defined east, (3) other assumptions. No one of these assumptions cun be proved from the consequence of them al], The ultimate principles are, in fact, mdemonstrable. On the other hand, if the conclusion turned out to be false, we could infer that some hypothesis, such as the existence of the straight line, was false. oh Anal. post. i. 10; Heath, Thirteen Books of Euclia’s Elements i.117 ff.) ‘But in the production of things for a purpose (of art or of Nature), the necessity works the other way: the assumption is that the end is to exist ar docs exist, and this necessitates that the antecedents shall exist or do exist; olherwise, as in mathematics the failure of the conclusion necessitates the non-existence of the premiss we start from (straight line), here the non-existence of the end PHYSICS, ΤΙ, ix.
of inverted parallelism between mathematics and the things that take place under the control] of nature. For a straight line being what it is, if (i) a triangle is straight-sided, then (ii) rts angles are equal to two right angles; but it does not follow that if (i) its angles are cqual to two right angles, then (i) the triangle must be straight-sided, though it does follow that if (ii) is not, i.e. its angles are not equal to two right angles, then (i) is not, 1.6, the triangle cannot be straight-sided.¢ But in purposeful constructions itis the other way about; for if (ji) the end is to be secured or actually has been secured, then (i) the antecedent conditions must be, or must have been, present; but just as in the case of the triangle the failure of the consequent (its angles are equal to two right angles) necessarily mvolves the failure of the antecedent (that the triangle be straight-sided), so here the failure of the material aztecedent (bricks or iron) necessarily carries with it the failure of the proposed end (house or saw). But in both cases it is the ‘ principle ’ or ‘ primary factor ’ that imposes the necessity upon the accessary one; for in the case of the triangle it is the premise that imposes a logical necessity on the conclusion (for the whole construcor purpose will be necessitated. For the end or purpose also is a principle or starting-point, not indeed of the process of realization, but of the process of reasoning; whereas in mathematics there is only the starting-point, or premise, of the reasoning, no action being aval?
Of. Eth. Nic. ἘΠῚ Ὁ 114%. In action we reason backwards from the proposed end (‘If I am to bring this ubout, what must I do first?’) along the chain of means, till we arrive at some action we can at once perform. We perform it, and so start the train of means from its ἀρχή (the beginning of the action and the conclusion of the reasoning) to the τέλος (the end of the action and the starting-point of the reasoning).—C.]
80 ARISTOTLE εἰ ἔσται οἰκία, ἀνάγκη ταῦτα γενέσθαι ἢ ὑπάρχειν a ts ἢ εἶναι, ἢ ὅλως τὴν ὕλην τὴν ἕνεκά του (οἷον < πλίνθους καὶ λίθους, εἰ οἰκία): οὐ μέντοι διὰ ταῦτά ἐστι τὸ τέλος--ἀλλ᾽ ἢ ὡς ὕλην---οὐδ᾽ ἔσται διὰ ταῦτα: ὅλως μέντοι μὴ ὄντων οὐκ ἔσται οὔτε ἡ οἰκία οὔθ᾽ 6 πρίων, ἡ μὲν εἰ μὴ of λίθοι, ὁ δ᾽ εἰ μὴ ὁ σίδηρος (οὐδὲ γὰρ ἐκεῖ αἱ ἀρχαί, εἰ μὴ τὸ τρίγωνον δύα dpGats). Φανερὸν δὴ ὅτι τὸ ἀναγκαῖον ἐν τοῖς φυσικοῖς τὸ ὡς ὕλη λεγόμενον καὶ αἱ κινήσεις αἱ ταύτης. καὶ ἄμφω μὲν τῷ φυσικῷ λεκτέαι at αἰτίαι, μᾶλλον δὲ ἡ τινὸς ἕνεκα’ αἴτιον yap τοῦτο τῆς ὕλης, ἀλλ ΕἸ @ a ὅλ \ i fn. \ δυ οὐχ αὕτη τοῦ τέλους. καὶ τὸ τέλος τὸ οὗ ἕνεκα, καὶ ἡ ἀρχὴ ἀπὸ τοῦ ὁρισμοῦ Kal τοῦ λόγου, 4 [Qr, ‘(as in the mathematical illustration, entities whose existence is assumed at the outset will not exist, if it is not true that the angles of a triangle are equal to two right angles).’ Aristotle makes confusion by at once comaring and contrasting logical and teleological necessity. Tis real point is that logical necessity works forward from premiss to conclusion, but in Nature there is not only mechanical necessity, working blindly forward from cause to effect, but ‘ hypothetical’ necessity, seen in the processes of Nature or of art, where a ‘ final cause’ fixes the goal to which the mechanical chain shall lead, rather than in other directions. The assumption, by the artist or by Nature, that this end shall be brought about, starts the whole process and accounts for its course.—C. | δ [Literally ‘ what is necessary in the things of Nature is what is so called in the sense of (the necessary) matter and its motions ᾽ {its inherent behaviour). These are a condition PHYSICS, II. 1x.
tion is logical, and there is no action at allin eel whereas in the other cases, though the purpose (which ig the principle that imposes the necessity on the material) has to do with action, yet it is only a logical necessity that it can impose, for it does not actually create or constitute the material. Thus, if there is to be a house, then stones, bricks and so forth, if not already on hand, must be produced (for at any rate they must be there). Or, to put it generally, the purpose-serving materials must be there, if the purpose is to be accomplished; but since they do not themselves fulfil the purpose, except materially, it does not follow that, if they are there, the purpose will be fulfled. To sum up: the materials will not account for the existence of the house or of the saw, though, if they are simply not there—no stones for the house, no iron for the saw—there will be no house and no saw (just as in the mathematical illustration straight-sidedness does not inhere in biorthogonahty, but cannot exist without it).¢ It is clear, then, that when physicists speak of necessity absolutely, they should limit the term to what is inherent in the material, and should recognize purposeful movement imposed upon the material as a distinct addition to its inherent qualities?» And though the physicist has to deal with both material and purpose, he 15 more deeply concerned with the latter; for purpose directs the moving causes that act upon the material, not the reverse. It is the goal that determines the purpose, and the principle of causation is derived from the definition and ration- ale of the end, in Nature just as much as in artificial sine qua non, but will not of themselves produce the desirable f end.’—C,] ARISTOTLE 500} ὥσπερ ἐν τοῖς κατὰ τέχνην, ἐπεὶ ἡ οἰκία τοιόνδε, τάδε δεῖ γίγνεσθαι καὶ ὑπάρχειν ἐξ ἀνάγκης, καὶ > XY e < f f 7 a t ΕἾ 3 é ἐπεὶ ἡ ὑγίεια τοδί, τάδε δεῖ γίγνεσθαι ἐξ ἀνάγκης καὶ ὑπάρχειν. οὕτως καὶ εἰ ἄνθρωπος τοδί, ταδί' εἰ δὲ ταδί, ταδί. ἴσως δὲ Kal ἐν TH λόγῳ ἐστὶ τὸ a i a,ὔ υ ἀναγκαῖον. ὁρισαμένῳ' γὰρ τὸ ἔργον τοῦ πρίειν iid é ὔ oe > 2 ww Ὑ 4 a ὅτι διαίρεσις τοιαδί: αὕτη δ᾽ οὐκ ἔσται, εἰ μὴ ἕξει ὀδόντας τοιουσδί' οὗτοι δ᾽ οὔ, εἰ μὴ σιδηροῦς. ἔστι yap καὶ ev τῷ λόγῳ ἔνια μόρια ws ὕλη τοῦ λόγου.
1 [ὁρισαμένῳ I. Bekker: ὁρισάμενοι E: ὁρισαμένου I.—C.]
* (Or, ‘Though, perhaps, we may also say that what is PHYSICS, II. 1x.
constructions..g.since this is what a house is, these things must necessarily be ready or be produced; and since this is what health is, such and such things must be provided to secure it. And in like manner, if this is what ‘man’ is, then there must antecedently be such and such things, and that they again may he there, such and such other things. And the same kind of ‘necessity’ may be traced on the conceptual side.* For if we define ‘sawing’ as such and such a method of dividing, it follows that it can only be accomplished by teeth of such and such a character, and these teeth can exist only if the saw be made ot ivon. For a definition, 1v0, contains constituent terms which are, as it were, its materials.
“necessary”? in this way is actually contained in the definilion.’]
BOOK III INTRODUCTION [In the last Book ‘Nature’ was defined as a principle of ‘movement’ (including change of all kinds). The next step is to define movement, and to study certain concep- tions which are held to be allied to movement: continuity, infinity, place, time, and void. Books LI. and ΓΝ, consist of a series of Essays on these subjects.
Chapters i.-iii. define movement or change as the passage from potential to actual existence: given something that is actually a and potentially ἡ, change is the process which ends in the realization of its capacity of being ὃ. Hence a change is something that is essentially incomplete so long as it lasts; the potential is all the while pro- gressively losing its character; but when it is transformed into complete actuality (ἐνέργεια), the change is over, This definition is substantiated by comparison with the inadequate conceptions of Plato and the Pythagoreans; and finally it is argued that, although a change or movement is the actualization of two potentialities— that of the mover and that of the moved—it occurs in the moved. This prelimmary account of movement will be amplified in Book V.
In Chapter iv. the essay on Infinity opens with a survey of the part played by this conception in earlicr systems, and a statement ef the problems it involves. Among these, the physicist is most concerned with the question whether there exists an infinite material body. That no such body can actually exist is proved, chiefly by means of the doctrine that sensible bodies have ‘ natural places’ PHYSICS, HI. INTRODUCTION (of. De caelo i. 7-8). On the other hand, mfinity must exist in some sense 3 otherwise time would not be unlimited in duration, there would he indivisible magnitudes (for it would not be possible to carry the process of division beyond a certain point), and the series of numbers would be limited. In spatial magnitude there 1s the potentiality of unlunited division that can never be realized by actual division into an unlimited number of parts. Conversely, there is the potentially unlimited series converging to a finite sum. Mathematical demonstrations do not require uw line of infinite length, but only a finite line as long as the mathematician chooses to suppose. There 1s no actual straight line greater than the diameter of the physical world-sphere. Time and number, on the other hand, are infinite divergent series From the fact that magnitude is infinitely divisible it follows that number ean be in- creased without limit Gee Gen. Introd. pp. Iaxxix δ}: but number is limited in the other direction, 7.7. there 18 a smallest, but not a greatest number. The infinity of Time is a consequence of the infinity of motion, which Time measures.
The result of this analysis ig that ‘Infinity’ means ‘ the open possthility of more,’ and can therefore never be nehinteed 04 Γ CHAPTER I ARGUMENT [Nature having been defined as a principle of movement or change, we must first investigate the nature of movement. This will lead on to further studies of the associated con~ one of continuity, infinity, place, void, and time (200 Ὁ There are four classes of things that can change or move, and four corresponding kinds of change: (1) of substance, (2) of quality, (8) of quantity, (4) of place. (CE. the longer discussion in De gen. et corr. A 4.) Change is the process of actually realizing what exists potentially, in so far as it exists potentially (Ὁ 25-201 a 29).
The qualification ‘in so far as it earsts potentially’ is 8008 “Emel δ᾽ ἡ φύσις μὲν ἔστιν ἀρχὴ κινήσεως καὶ μεταβολῆς, ἡ δὲ μέθοδος ἡμῖν περὶ φύσεώς ἐστι, δεῖ μὴ λανθάνειν τί ἐστι κίνησις" ἀναγκαῖον γὰρ 1s ἀγνοουμένης αὐτῆς ἀγνοεῖσθαι καὶ τὴν φύσιν. διορισαμένοις δὲ περὶ κινήσεως πειρατέον τὸν αὐτὸν ἐπελθεῖν τρόπον περὶ τῶν ἐφεξῆς. δοκεῖ δ᾽ ἡ κίψησις εἶναι τῶν συνεχῶν, τὸ δ᾽ ἄπειρον ἐμ- φαίνεται πρῶτον ἐν τῷ συνεχεῖ: διὸ καὶ τοῖς BOOK III CHAPTER I ARGUMENT (continued) added because movement is not the actualization of the whole character (say) of the bricks used for the process of building a house, but only of that part of their character which consists in their capacity tu serve as materials for the house. The movement or process of building is not the realization of the building materials ag bricks (they are bricks before the process begins), nor of therr potentiality of being a house (the house is the realization of that), but ὁ, their potentiality of serving as building materials G οἰκοδομητόν) (a 29-b 16.)
(Extracts from this chapter appear in Metaphysics K 9, where Mr. Ross’s commentary may be consulted.)—C.]
Since Nature is the principle of movement and change, and it is Nature that we are studying, we must understand what ‘movement’ is; for, if we do not know this, neither do we understand what Nature is. When we have defined the meaning of movement or progress from this to that, we must attempt in the same way a discussion of the associated conceptions to which it leads. Now, movement is clearly one of the things we think of as ‘ continuous,’ and it is in connexion with continuity that we first encounter the concept of the ‘ unlimited.’ And this ARISTOTLE ARISTOTLE te ἰῷ 200b ὁριζομένοις τὸ συνεχὲς συμβαίνει προσχρήσασθαι 50 πολλάκις τῷ λόγῳ τῷ τοῦ ἀπείρου, ὡς τὸ εἰς \ ἄπειρον διαιρετὸν συνεχὲς ὄν. πρὸς δὲ τούτοις ἄνευ τόπου καὶ κενοῦ καὶ χρόνου κίνησιν ἀδύνατον εἶναι. δῆλον οὖν ὡς διά τε ταῦτα καὶ διὰ τὸ πάντων εἶναι κοινὰ καὶ καθόλου ταῦτα πᾶσι, 4 σκεπτέον προχειρισαμένοις περὶ ἑκάστου τούτων' ὑστέρα γὰρ ἡ περὶ τῶν ἰδίων θεωρία τῆς περὶ τῶν 2 κοινῶν ἐστιν.
Καὶ πρῶτον, καθάπερ εἴπαμεν, περὶ κινήσεως.
ν ὃ la 4 A > λ f ld ‘ δὲ ὃ / ἔστι δή τι τὸ μὲν ἐντελεχείᾳ μόνον, τὸ δὲ δυνάμει καὶ ἐντελεχείᾳ, TO μὲν τόδε TL, TO δὲ τοσόνδε, TO δὲ τοιόνδε, καὶ ἐπὶ τῶν ἄλλων τῶν τοῦ ὄντος κατηγοριῶν ὁμοίως. τοῦ δὲ πρός τι τὸ μὲν καθ᾽ 8ὺ ὑπεροχὴν λέγεται καὶ κατ᾽ ἔλλειψιν, τὸ δὲ κατὰ τὸ ποιητικὸν καὶ παθητικὸν καὶ ὅλως κινητικόν τε καὶ κινητόν! τὸ γὰρ κινητικὸν κινητικὸν τοῦ κινητοῦ, καὶ τὸ κινητὸν κινητὸν ὑπὸ τοῦ κινητικοῦ.
Οὐκ ἔστι δέ τις κίνησις παρὰ τὰ πράγματα.
2 Sec Gen. Introd. Ὁ. Ixxwii.
> [Viz., pure Intelligences, After μόνον (1, 26) probably «τὸ δὲ δυνάμει» should be inserted (as in Afet. 1065 b 53 so Spengel and others), so as to include in the classification potentialities never actualized, such as the infinite. The third class (δυνάμει καὶ ἐντελεχείᾳ) contains natural objects (matter +form).—C.]
ὁ [κινητικόν, as distinguished from κινοῦν at 202 a 16 κινητικὸν μὲν γάρ ἐστι τῷ δύνασθαι, κινοῦν δὲ τῷ évepyetv.—,] PHYSICS, II. 1.
is why in definitions of continuity this concept of the ‘unlimited ’ frequently occurs, as when we say that the continuous is that which is susceptible of division without limit.¢ Further, movement (at is said) cannot occur except in relation to place, void, and time. Evidently, then, for these reasons and because these four things—movement, place, void, and time—are universal conditions common to all natural phenomena, we must consider each of them on the threshold of our inquiry; for the treatment of peculiar properties must come after that of properties common to all natural things.
We must begin, then, as already said, with move- ment in general or progress from this to that. Now, some potentialities never exist apart, but always reveal themselves as actualized; others, while they are something actually, are capable of becoming something else than they are, that is to say, have potentialities not realized at the moment; and these potentialities may concern their substantive being (what they are) or their quantity or their qualities; and so on with the other categories of existence. And under the category of ‘ relation’ may be relations between the ‘ more’ and the ‘ less,’ or between that which is active and that which is acted on, and generally between that which * moves’ (or changes) something as the agent and that which is moved (or changed) by it as the patient. For that which has the power of producing a change can only act in reference to a thing capable of being changed; and that which is capable of being changed can only suffer change under the action of that which has the power to change it.° Now, motion and change cannot exist in them- VOL. I ο 198 ARISTOTLE 200b μεταβάλλει yap τὸ μεταβάλλον ἀεὶ ἢ κατ᾽ οὐσίαν ἢ κατὰ ποσὸν ἢ κατὰ ποιὸν ἢ κατὰ τόπον" κοινὸν 88 δ᾽ ἐπὶ τούτων οὐδὲν ἔστι λαβεῖν (ὥς Paper) ὃ 21a οὔτε τόδε οὔτε ποσὸν οὔτε ποιὸν οὔτε τῶν ἄλλων κατηγορημάτων οὐθέν: ὥστ᾽ οὐδὲ κίνησις οὐδὲ μεταβολὴ οὐθενὸς ἔσται παρὰ τὰ εἰρημένα, μη- δενός γε ὄντος παρὰ τὰ εἰρημένα. Ἕκαστον δὲ διχῶς ὑπάρχει πᾶσιν, οἷον τὸ τόδε (τὸ μὲν γὰρ μορφὴ αὐτοῦ, τὸ δὲ στέρησις), καὶ κατὰ τὸ ποιόν (τὸ μὲν γὰρ λευκὸν τὸ δὲ μέλαν), καὶ κατὰ τὸ ποσὸν τὸ μὲν τέλειον τὸ δ᾽ ἀτελές" ὁμοίως δὲ καὶ κατὰ τὴν φορὰν τὸ μὲν ἄνω τὸ δὲ κάτω ἢ τὸ μὲν κοῦφον τὸ δὲ βαρύ. ὥστε κινήσεως καὶ μεταβολῆς ἐστιν εἴδη τοσαῦτα ὅσα τοῦ ὄντος. 10 Διῃρημένου δὲ καθ᾽ ἕκαστον γένος τοῦ μὲν ἐντελεχείᾳ τοῦ δὲ δυνάμει, ἡ τοῦ δυνάμει ὄντος ἐντελέχεια, ἧ τοιοῦτον, κίνησίς ἐστιν" οἷον τοῦ μὲν ἀλλοιωτοῦ, ἧ ἀλλοιωτόν, ἀλλοίωσις, τοῦ δὲ αὐξητοῦ καὶ τοῦ ἀντικειμένου φθιτοῦ (οὐδὲν γὰρ ὄνομα κοινὸν ἐπ᾽ ἀμφοῖν) αὔξησις καὶ φθίσις, τοῦ τὸ δὲ γενητοῦ καὶ φθαρτοῦ γένεσις καὶ φθορά, τοῦ δὲ φορητοῦ φορά. ὅτι δὲ τοῦτό ἐστιν ἡ κίνησις, 5 [Aristotle seems to be attacking Plato for discussing Change or Motion as one of the ‘ widest kinds’ (Soph, 254.8 ff.). There is no such thing as Change in itself, apart from something that changes.—C.]
5 [rotrwr, NeaUys ‘these classes of iH το δι sar quality, ete.—which are ultimate irreducible heads under one (and only one) of which anything that exists can be classified. Cf. Μοὶ. 1065 Ὁ 7.—C.]
9 [Literally, ‘ each (of these categories) belongs to all (ts subjects) in two ways.’—C.]
4 See Book V, ch, i.
PHYSICS, IIT. 1.
selves apart from what moves and changes.* Tor, wherever anything changes, it always changes either from one thing to another, or from one magnitude to another, or from one quahty to another, or from one place to another; but there is nothing that embraces all these kinds of change® in common, and is itself neither substantuve nor quantitive nor qualitive nor pertaining to any of the other categories, but existing in detachment; so neither can move- ment or change exist independently of these, for there is nothing independent of them, Again, in each of these four cases, there are two poles between which the change moves;¢ in sub- stantive existence, for example, form and shortage from form; in quality, white and black, in quantity, the perfectly normal and an achievement short of perfection“; and so, too, in the case of vection, up and down, or the action of levity and gravity. So there are as many kinds of change as there are categories of existence.
Reverting, therefore, to the universal distinction already established between ‘ being-at-the-goal’ in actuality and being in potentiality ‘ such-as-is-capable- of-attaining-the-goal,’ we can now define motion or change as the progress of the reahzing of a potentia- ality, qua potentiality, e.g. the actual progress of qualitive modification in any modifiable thing qua modifiable; the actual growing or shrinking (for we have no single word to include them both) of any- thing capable of expanding or contracting; the process of coming into existence or passing out of it of that which is capable of so coming and passing 3 the actual moving of the physical body capable of changing its place. That this is what we really mean 20 τῷὸ δι ARISTOTLE ἐντεῦθεν δῆλον: ὅταν γὰρ τὸ οἰκοδομητόν, ἧ τοιοῦτον αὐτὸ λέγομεν εἶναι, ἐντελεχείᾳ ἢ, οἶκοδομεῖται, καὶ ἔστι τοῦτο οἰκοδόμησις" ὁμοίως δὲ καὶ μάθησις καὶ ἰάτρευσις καὶ κύλισις καὶ ἅλσις καὶ ἅδρυνσις καὶ γήρανσις.
" "Emel δ᾽ ἔνια ταὐτὰ καὶ δυνάμει καὶ ἐντελεχείᾳ ἐστίν--οὐχ ἅμα δέ, ἢ οὐ κατὰ τὸ αὐτό, ἀλλ᾽ οἷον θερμὸν μὲν δυνάμει ψυχρὸν δὲ ἐντελεχείᾳ---πολλὰ ἤδη ποιήσει καὶ πείσεται ὑπ᾽ ἀλλήλων: ἅπαν γὰρ ἔσται ἅμα ποιητικὸν καὶ παθητικόν. ὥστε καὶ τὸ κινοῦν φυσικῶς κινητόν" πᾶν γὰρ τὸ τοιοῦτον κινεῖ κινούμενον καὶ αὐτό. δοκεῖ μὲν οὖν τισιν ἅπαν κινεῖσθαι τὸ Kwotv: od μὴν ἀλλὰ περὶ τούτου μὲν ἐξ ἄλλων ἔσται δῆλον ὅπως ἔχει---ἔστι γάρ τι κινοῦν καὶ ἀκίνητον--- δὲ τοῦ δυνάμει 5 [ie., things in the sublunary world. (The Heavens, whose lowest sphere is conterminous with the uppermost stratum (fire) of the sublunary world, act upon this world, but are in no way uffected in return. De gen. ef corr. A 6.) The clause ἅπαν yap...παθητικόν Seems to mean that every such thing has both potentialities at once.—C.]
ὃ The important and easily overlooked point here is that Aristotle had no conception of inertia, the fatal defect which runs through his physics. Having no conception of inertia, he could not conceive why a projectile goes forward after it leaves the hand that is hurling or thrusting it forward. He gives obviously unadequate alternatives as explanations of this, which he is never quite willing to father, but which he allows to pass with some uneasiness (see Book V. ch. vi). But in other respects he accepts the principles which the differences of idiom easily allow us to think we understand when we do not really do so. If one brick by being thrown upon another sets a whole row of bricks on the fall one after another, Aristotle takes this to show not only that every fresh motion must have been started by a moving body already moving, but also that every moving PHYSICS, III. τ.
PHYSICS, III. τ.
by motion or change may be shown thus: building material is actualizing the potentialities in virtue of which we call it ‘ building material’ when it is in the act of being built into a structure, and this act is the process or ‘movement’ of ‘ building’; and so too with other processes—learning, healing, rolling, jumping, maturing, aging.
And since in certain cases the same thing may have both an actuahty and a potentiality (not indeed at the same time or not in the same respect, but potentially hot, for instance, and actually cold), it follows that many things act on, and are acted on by, each other; for anything will be at once capable of acting and of being acted upon.* And so it happens that every physical body which causes motion must be capable of being moved; for whenever it causes motion it is itself under the action of some other body which is keeping it in motion.o But the inference that has sometimes been drawn, that there is no cause of a thing being in motion, which cause is not itself in motion, is false. The truth in this matter will be explained later on;° suffice it now to say that there zs a canse of things being in motion, which cause is itself immovable; but motion is the body during the whole time that it is in motion must be being kept in motion by some other body, which other body is itself not only in motion but kept in motion by some other body for the whole time during which it is in motion, Few of us are conscious of the wide place that the law of inertia —that a body in motion will go on of itself at the same speed and in the sume direction until something else affects it— takes in our actual thinking. We all assume its constant action subconsciously without ever thinking of it at all. But Aristotle, who had no conception of it, was always conscious of having to do without it. 5 [In Book VIII. 1-6.—C.]
80 8 a σι ARISTOTLE ὄντος, ὅταν ἐντελεχείᾳ dv ἐνεργῇ ody ἣ αὐτὸ ἀλλ᾽ ἡ κινητόν, κίνησίς ἐστιν.
Λέγω δὲ τὸ ἢ ὧδί, ἔστι γὰρ ὁ χαλκὸς δυνάμει ἀνδριάς, ἀλλ᾽ ὅμως οὐχ ἡ τοῦ χαλκοῦ ἐντελέχεια, ἦ χαλκός, κίνησίς ἐστιν’ οὐ γὰρ τὸ αὐτὸ τὸ χαλκῷ εἶναι καὶ δυνάμει τινὶ κινητῷ, ἐπεὶ εἰ ταὐτὸν ἦν ἁπλῶς καὶ κατὰ τὸν λόγον, ἦν ἂν ἡ τοῦ χαλκοῦ, ἢ χαλκός, ἐντελέχεια κίνησις" οὐκ ἔστι δὲ ταὐτόν, ὡς εἴρηται. (δῆλον δ᾽ ἐπὶ τῶν ἐναντίων" τὸ μὲν γὰρ δύνασθαι ὑγιαίνειν καὶ δύνασθαι κάμνειν ἕτερον---καὶ γὰρ ἂν τὸ,κάμνειν καὶ τὸ ὑγιαίνειν ταὐτὸν ἦν--τὸ δὲ ὑποκείμενον καὶ τὸ ὑγιαῖνον καὶ τὸ νοσοῦν, εἴθ᾽ ὑγρότης εἴθ᾽ αἷμα, ταὐτὸν καὶ ἕν ἐπεὶ δ᾽ οὐ ταὐτόν (ὥσπερ οὐδὲ χρῶμα ταὐτὸν καὶ ὁρατόν), ἡ τοῦ δυνατοῦ, ἧ δυνατόν, ἐντελέχεια avepov ὅτι κίνησίς ἐστιν.
Ὅτι μὲν οὖν ἐστιν αὕτη, καὶ ὅτι συμβαίνει τότε κινεῖσθαι ὅταν ἡ ἐντελέχεια 7 αὕτη, καὶ οὔτε πρότερον οὔτε ὕστερον, δῆλον. ἐνδέχεται γὰρ ἕκαστον ὁτὲ μὲν ἐνεργεῖν ὁτὲ δὲ μή, οἷον τὸ 1 [αὐτή con} Christ at Wet. 1066 ἢ 85; αὕτη codd. (in both places),—C.]
@ [8e, ἐντελέχεια, which Bonitz inserted after ὄντος, But see Met. 1065 b 21, where this clause follows a sentence from which the word can be supplied.—C.]
ὃ ΓΥ here translated the Berlin text; but for ἢ αὐτὸ ἢ ἄλλο most editors read (with one ms. here and with E and others at Met, 1065 b 22) οὐχ ἢ, αὐτὸ ἀλλ᾽ ἡ κινητόν, This, as Ross remarks on Afet., loc. cit., is shown to be the true reading by the explanation of 4 which follows (in both places). Ross renders: ‘The complete reality of that which exists potentially, when it 1s completely real and actual, not gua itself, but gua movable, is peae nai & ¢ (The parallel passage (with slight verbal variations) in PHYSICS, ITI. τ.
functioning ¢ of a movable thing, all the time that it is bringing its potentiality into act, not qua itself, but qua movable.® To ulustrate what I mean by ‘ gua’ this or that. The bronze is potentially the statue, but neither to be the statue nor to move or change in any respect is the self-realizing of the bronze qua bronze; for it is not the same thing to be bronze and to be poten- tially movable or changeable. Were it the same thing, absolutely and by definition, then indeed moving would be its self-realization; but it is not the same. (It is clear in the case of opposites: the potentiality of health and the potentiality of disease are different things—otherwise being diseased and being healthy would be identical—but whatever it is, humour or blood, that is subject to the healthy or unhealthy condition is one and the same thing in both cases.) And since it is not the same (any more than colour and visibility, for instance, are the same), it is clear that motion must be the realization of the specific potentiality in question and of the subject only qua seat of this specific potentiality.
Clearly, then, this is the nature of movement, and a thing is moving just as long as it is actually function- ing in this particular way, and neither before nor after. For anything capable of this special kind of functioning may be exercising it at one time, but not at another; for instance,® the building materials are te Met. 1066 « 1 is translated more literally by Mr. Rass: ‘e9., the “ buildable,” gua‘ buildable”; and the actuality of the “ buildable ” qua “ buildable” is building. Tor the actualily 1s either this—building—or the house. But when the house exists, it is no longer “ buildable’; the ‘* build- able’ is what és being built. The actuality then must be the building, and the building is a movement.’—C.]
ARISTOTLE 2010 οἰκοδομητόν, Kal ἡ τοῦ οἰκοδομητοῦ ἐνέργεια, 107) οἰκοδομητόν, οἰκοδόμησίς ἐστιν (ἢ yap οἰκοδόμησις ἡ ἐνέργεια τοῦ οἰκοδομητοῦ ἢ ἡ οἰκία" ἀλλ᾽ ὅταν οἰκία ἢ, οὐκέτ᾽ οἰκοδομητὸν ἐστιν, οἶκοa A Sopetra, δὲ τὸ οἰκοδομητόν: ἀνάγκη ἄρα τὴν οἰκοδόμησιν τὴν ἐνέργειαν elvar), ἡ δ᾽ οἰκοδόμησις κίνησίς τίς ἐστιν. ἀλλὰ μὴν ὁ αὐτὸς ἐφαρμόσει 1 λόγος καὶ ἐπὶ τῶν ἄλλων κινήσεων.
CHAPTER II ARGUMENT [The definition af motion is compared with the conceptions of the Pythagoreans and Plato, which were inadequate but prompted by a dim perception of the truth that movement is something incomplete (201 Ὁ 16-202 a 8).
In tha sublunary world the action of the mowing body is accompanied by action upon it, so that the mover is also Ὅτι δὲ καλῶς εἴρηται, δῆλον καὶ ἐξ ὧν of ἄλλοι : περὶ αὐτῆς λέγουσι, καὶ ἐκ τοῦ μὴ ῥᾷδιον εἶναι διορίσαι ἄλλως αὐτήν. οὔτε γὰρ τὴν κίνησιν καὶ τὴν μεταβολὴν ἐν ἄλλῳ γένει θεῖναι δύναιτ᾽ ἄν τις.
SAX δὲ a ε θέ, γ Ἂν », 20 O77) OV € σκοποῦσιν ὡς TEAC αὕτην ἔνιοι, « [οὔτε has no grammatical correlate.—C.]
PHYSICS, ΠῚ, 1-11.
functioning as materials for building only so long as they are in process of being built with; for as soon as the edifice itself is actually raised, the functioning of what were matenals for a house is merged in the functioning of the house itself; but as long as they are being built with, they are functioning as materials forahouse. The act of building, then, is the energiz- ing or bringing into actuality of the potentiality of the materials gua materials; and the passage of the materials of a house into the texture of the house itself, so long as it is in progress, is their ‘movement’ qua materials of building. And this is the theory of all the other ‘ movements’ equally.
CHAPTER II ARGUMENT (continued) moved. This justifies our defining motion as the actualiza- tion of what is capable of being moved (not, as one might expect, of causing motion) (a 38-9).
The moving cause carries with it some element of form, which will serve as a principle of movement (a 9-12). (Extracts from this chapter, Met. 1066 a 7-27.)—C.]
Tuat we have found the true definition becomes clear when we note what others have said about it and the difficulties presented by all their definitions, For, in the first place,? it is not possible to place movement and change under any other heading, nor have any previous definitions justified themselves. This comes out clearly enough when we consider 25 80 ARISTOTLE ἑτερότητα καὶ ἀνισότητα καὶ τὸ μὴ ὃν φάσκοντες εἶναι τὴν κίνησιν' ὧν οὐδὲν ἀναγκαῖον κινεῖσθαι--- οὔτ᾽ ἂν ἕτερα ἢ, οὔτ᾽ ἂν ἄνισα, οὔτ᾽ ἂν οὐκ ὄντα —dAn οὐδ᾽ ἡ μεταβολὴ οὔτ᾽ εἰς ταῦτα οὔτ᾽ ἐκ τούτων μᾶλλόν ἐστιν ἢ τῶν ἀντικειμένων. αἴτιον δὲ τοῦ εἰς ταῦτα τιθέναι ὅτι ἀόριστόν τι δοκεῖ εἶναι a rg ἡ κίνησις, THs δὲ ἑτέρας συστοιχίας αἱ ἀρχαὶ διὰ τὸ στερητικαὶ εἶναι ἀόριστοι: οὔτε γὰρ τόδε οὔτε τοιόνδε οὐδεμία αὐτῶν ἐστιν, [dre]' οὐδὲ τῶν ἄλλων κατηγοριῶν. id eet A cal 3 \ f " Τοῦ δὲ δοκεῖν ἀόριστον εἶναι τὴν κίνησιν αἴτιον ὅτι οὔτε εἰς δύναμιν τῶν ὄντων οὔτε εἰς ἐνέργειαν μὴ - ~ LY ἔστι θεῖναι αὐτὴν ἁπλῶς" οὔτε γὰρ τὸ δυνατὸν ποσὸν εἶναι κινεῦται ἐξ ἀνάγκης, οὔτε τὸ ἐνεργείᾳ ποσόν, ἥ τε κίνησις ἐνέργεια μέν τις εἶναι δοκεῖ, ἀτελὴς δέ' αἴτιον δ᾽ ὅτι ἀτελὲς τὸ δυνατὸν οὗ 1 [ὅτι del. Bonitz.—C. ] * {The Pythagoreans, who in their list of ten contrary popes. in parallel columns (συστοιχίαι, Met. 986 a 22 ff.), eaded by ‘ Limit’ and ‘ Unhmited,’ included κινούμενον under the Unlimited; and Plato, whose pupil Hermodorus (ap. Simplic. 247. 33) says that all things related to one another as * great’ to ‘small’ admit degrees of ‘ more’ or ‘ less,’ so that they can go on to infinity in either direction— towards the still more, or the still less, But things described as the equal or as that which is αὐ rest or in tune do not admit degrees of more or less. There is always something more unequal than what is unequal, moving more than what is moving, more out of tune than what 15. out of tune. So what is of this nature is unstable, formless, unlimited, and may be called ‘ not-being.’ Cf. note on 187 a 17.—C.]
» [Literully, ‘the principles in the second column are regarded as indefinite because of their negative character.’ ‘Not only is συστοιχία used of the Pythagorean list of oppoutes, but Aristotle himself recogmizes a positive συστοιχία, or column including such terms as being, unity, substance, PHYSICS, HT. ας.
PHYSICS, HT. ας.
how movement has been defined by some 4as ὁ otherwisencss ' or “ unequalness’ or non-existence. Tor none of these—being ‘ other’ or ‘ unequal’ or ‘non-existent,’ to wit-—necessarily carries movement with it; nor jis change either into or out of these any more than into or out of their opposites. The reason why motion was brought under these negative definitions was because it seemed to share the indefinite and elusive character of the negative hmb of every antithesis.” For nether motion nor any of these negations seems to be a‘ thing’ or a‘ quality’ or to come under any other category.
Now the indefinite character attributed to motion is due to our inability to place it frankly either amongst the potentialities or amongst the realized functions of any kind of ‘ thing’ as such; for there is no necessity in anything’s changing its magnitude (for instance) either because it is potentially or because it is actually of this or that specified magni- tude. ¢ And the fact turns out to be that movement is a realization, but an uncompleted one; because a and a negative συστοιχία including not-being, plurality, not- substance,.. In each case the negative 1s known, not per se but as the negation of the positive term’ (Ross on Met.
4 (Literally, ‘ And movement appears to be an actuality, but incomplete; the reason is that the potential, of which it is the actuality, is complete.” Cf. Met. 1048 Ὁ 29, ‘Every movement 1s incomplete, for it is not true that at the same time we are taking a walk and have taken a walk, are being moved and have been moved; whereas it is true that the same thing at the same time has seen and 1s seeing, or has thought and is thinkmg. The latter sort of process is an actuality (ἐνέργεια), the former a movement («lvyors),’ Thus a movement is a process which is never complete till it is over; while an activity, 8.5. seeing, is complete at every moment of its duration.—C.]
85 a ARISTOTLE ἐστιν ἐνέργεια. καὶ διὰ τοῦτο δὴ χαλεπὸν αὐτὴν λαβεῖν τί ἐστιν ἢ γὰρ εἰς στέρησιν ἀναγκαῖον θεῖναι ἢ εἰς δύναμιν ἢ εἰς ἐνέργειαν ἁπλῆν, τούτων δ᾽ οὐδὲν φαίνεται ἐνδεχόμενον. λείπεται τοίνυν ὁ εἰρημένος τρόπος, ἐνέργειαν μέν τινα εἶναι, τοιαύ- τὴν δ᾽ ἐνέργειαν οἵαν εἴπαμεν---χαλεπὴν μὲν ἰδεῖν, ἐνδεχομένην δ᾽ εἶναι.
Κινεῖται δὲ καὶ τὸ κινοῦν ὥσπερ εἴρηται, πᾶν τὸ δυνάμει ὃν κινητὸν καὶ οὗ ἡ ἀκινησία ἠρεμία ἐστίν (ᾧ γὰρ ἡ κίνησις ὑπάρχει, τούτῳ ἡ ἀκινησία ἠρεμία)" τὸ γὰρ πρὸς τοῦτο ἐνεργεῖν, ἧ τοιοῦτον, αὐτὸ τὸ κινεῖν ἐστι' τοῦτο δὲ ποιεῖ θίξει, ὥστε ἅμα καὶ πάσχει. διὸ ἡ κίνησις ἐντελέχεια τοῦ 5 (Or: ‘ Now that which causes motion in the way above mentioned (ὥσπερ εἴρηται alludes to φυσικῶς in the passage referred to, 201a28 ὥστε καὶ τὸ κινοῦν φυσικῶς κινητύν), —namely anything that is a potential movable or whose motionlessness can be described as “ rest” (for “ rest” means the absence of motion in a thing to which motion properly belongs)—is also itself in motion: for the act of causing motion is precisely acting upon that which is thus moyable, as such; and this effect is produced by contact, so that the mover is acted upon at the same time that it acts, Accordingly, motion is the actualization of the movable, qua movable, but this oceurs by contact with the thing capable of moving it, so that this latter thing is simul- taneously affected (by some further thing moving 1), But the thing which is actually causmg motion (unlike the moved, which is potential and incomplete while the motion lasts) will always bring with it some element of (actual) form...—C.
> [Contact and action-passion between bodies are ex~- haustively discussed in De gen. δὲ corr. A 6. The Heavens ‘touch ' the sublunary world and communicate motion to it, PHYSICS, 111. u.