The manner in which the mover moves the moved is not always the same: whereas one kind of mover can only impart motion by being itself moved, another kind can do so though remaining itself unmoved. Clearly therefore we must [15] recognize a corresponding variety in speaking of the acting thing too; for the mover is said to act and the acting thing to impart motion. Nevertheless there is a difference and we must draw a distinction. For not every mover can act, if we are to contrast agent with patient and patient is to be applied only to those things whose motion is a quality—i.e. a quality, like white or hot, in respect to which they are [20] altered: on the contrary, moving is wider than acting. Still, so much, at any rate, is clear: the things which are such as to impart motion in one sense will touch the things which are such as to be moved by them, but in another sense they will not. But the definition of touching in general applies to things which, having position, are such that one is able to impart motion and the other to be moved, while reciprocal touching holds between two things, one able to impart motion and the other able to be moved in such a way that action and passion are predicable of them.
[25] As a rule, no doubt, if A touches B, B touches A. For indeed practically all the movers within our ordinary experience impart motion by being moved: in their case, what touches must, and evidently does, touch something which touches it. Yet it is possible—as we sometimes say—for the mover merely to touch the moved, and that which touches need not touch a thing which touches it. Nevertheless it is commonly supposed that touching must be reciprocal, because movers which belong to the [30] same kind as the moved impart motion by being moved. Hence if anything imparts motion without itself being moved, it may touch the moved and yet itself be touched by nothing—for we say sometimes that the man who grieves us touches us, but not that we touch him.
7 · The account just given may serve to define the contact which occurs in [323b1] the things of nature. Next in order we must discuss action and passion. Our predecessors’ theories on the subject are conflicting. For most thinkers are unanimous in maintaining that like is always unaffected by like, because (as they argue) neither is more apt than the other either to act or to suffer action, since all [5] the properties which belong to the one belong identically and in the same degree to the other; and that unlikes, i.e. differents, are by nature such as to act and suffer action reciprocally. For even when the smaller fire is destroyed by the greater, it suffers this effect (they say) owing to its contrariety—since the great is contrary to the small. But Democritus dissented from all the other thinkers and maintained [10] a theory peculiar to himself. He asserts that agent and patient are identical, i.e. like. It is not possible (he says) that others, i.e. differents, should suffer action from one another: on the contrary, even if two things, being others, do act in some way on one another, this happens to them not qua others but qua possessing an identical property.
Such, then, are the views, and it looks as if the statements of their advocates [15] were in manifest conflict. But the reason of this conflict is that each group is in fact stating a part, whereas they ought to have taken a view of the subject as a whole. For if two things are like—absolutely and in all respects without difference from one another—it is reasonable to infer that neither is in any way affected by the other. Why, indeed, should the one of them tend to act any more than the other? [20] Moreover, if like can be affected by like, a thing can also be affected by itself; and yet if that were so—if like tended in fact to act qua like—there would be nothing indestructible or immovable, for everything would move itself. And the same consequence follows if the two things are absolutely other, i.e. in no respect identical. Whiteness could not be affected in any way by a line nor a line by [25] whiteness—except perhaps accidentally, viz. if the line happened to be white or black; for unless two things either are, or are composed of, contraries, neither drives the other out of its natural condition. But since only those things which either involve a contrariety or are contraries—and not any things selected at random—are [30] such as to suffer action and to act, agent and patient must be like (i.e. identical) in kind and yet unlike (i.e. contrary) in species. (For by nature body is affected by body, flavour by flavour, colour by colour, and so in general what belongs to any kind by a member of the same kind—the reason being that contraries are in every [324a1] case within a single identical kind, and it is contraries which reciprocally act and suffer action.) Hence agent and patient must be in one sense identical, but in another sense other than (i.e. unlike) one another. And since patient and agent are [5] generically identical (i.e. like) but specifically unlike, while it is contraries that exhibit this character: it is clear that contraries and their intermediates are such as to suffer action and to act reciprocally—for indeed it is these that constitute the entire sphere of passing-away and coming-to-be.
We can now understand why fire heats and the cold thing cools, and in general [10] why the active thing assimilates to itself the patient. For agent and patient are contrary to one another, and coming-to-be is a process into the contrary: hence the patient must change into the agent, since it is only thus that coming-to-be will be a process into the contrary. And, again, it is intelligible that the advocates of both [15] views, although their theories are not the same, are yet in contact with the nature of the facts. For sometimes we speak of the substratum as suffering action (e.g. of the man as being healed, being warmed and chilled, and similarly in all the other cases), but at other times we say what is cold is being warmed, what is sick is being healed: and in both these ways of speaking we express the truth, since in one sense it is the matter, while in another sense it is the contrary, which suffers action. (We make the [20] same distinction in speaking of the agent; for sometimes we say that the man, but at other times that what is hot, produces heat.) Now the one group of thinkers supposed that agent and patient must possess something identical because they fastened their attention on the matter; while the other group maintained the opposite because their attention was concentrated on the contraries.
[25] We must conceive the same account to hold of action and passion as that which is true of being moved and imparting motion. For things are called movers in two ways. Both that which contains the origin of the motion is thought to impart motion (for the origin is first amongst the causes), and also that which is last in relation to the moved thing and to the coming-to-be. A similar distinction holds also of the [30] agent; for we speak both of the doctor and of the wine as healing. Now, in motion, there is nothing to prevent the first mover being unmoved (indeed, as regards some this is actually necessary) although the last mover always imparts motion by being itself moved; and, in action, there is nothing to prevent the first agent being unaffected, while the last agent only acts by suffering action itself. For if things have not the same matter, the agent acts without being affected; thus the art of healing produces health without itself being acted upon in any way by that which is [324b1] being healed. But the food, in acting, is itself in some way acted upon: for, in acting, it is simultaneously heated or cooled or otherwise affected. Now the art of healing corresponds to an origin, while the food corresponds to the last (i.e. contiguous) mover.
Those active powers, then, whose forms are not embodied in matter, are [5] unaffected; but those whose forms are in matter are such as to be affected in acting. For we maintain that one and the same matter is equally, so to say, the basis of either of the two opposed things—being as it were a kind; and that that which can be hot must be made hot, provided the heating agent is there, i.e. comes near. Hence [10] (as we have said) some of the active powers are unaffected while others are such as to be affected; and what holds of motion is true also of the active powers. For as in motion the first mover is unmoved, so among the active powers the first agent is unaffected.
The active power is a cause in the sense of that from which the process originates; but the end, for the sake of which it takes place, is not active. (That is [15] why health is not active, except metaphorically.) F
or when the agent is there, the patient becomes something; but when states are there, the patient no longer becomes but already is—and forms (i.e. ends) are a kind of state. As to the matter, it (qua matter) is passive. Now fire contains the hot embodied in matter; but a hot separate from matter (if such a thing existed) could not suffer any action. Perhaps, indeed, it is impossible that the hot should exist in separation from matter; but if [20] there are any entities thus separable, what we are saying would be true of them.
We have thus explained what action and passion are, what things exhibit them, why they do so, and in what manner. We must go on to discuss how it is possible for action and passion to take place.
8 · Some philosophers think that the last agent—the agent in the strictest [25] sense—enters in through certain pores, and so the patient suffers action. It is in this way, they assert, that we see and hear and exercise all our other senses. Moreover, according to them, things are seen through air and water and other transparent bodies, because such bodies possess pores, invisible indeed owing to their minute-ness, [30]but close-set and arranged in rows—the more transparent the body, the more so.
Such was the theory which some philosophers (including Empedocles) advanced in regard to the structure of certain bodies. They do not restrict it to the bodies which act and suffer action; but combination too, they say, takes place only between bodies whose pores are in reciprocal symmetry. The most systematic theory, however, and one that applied to all bodies, was advanced by Leucippus and [325a1] Democritus: and, in maintaining it, they took as their starting-point what naturally comes first.
For some of the older philosophers thought that what is must of necessity be one and immovable. The void, they argue, is not; but unless there is a void with a separate being of its own, what is cannot be moved—nor again can it be many, since [5] there is nothing to keep things apart. And they hold that the view that the universe is not continuous but consists of separate things in contact is no different from the view that there are many (and not one) and a void. For if it is divisible through and through, there is no one, and no many either, but the Whole is void; while to maintain that it is divisible at some points, but not at others, looks like an [10] arbitrary fiction. For up to what limit is it divisible? And for what reason is part of the Whole indivisible, i.e. a plenum, and part divided? Further, they maintain, it is equally necessary to deny the existence of motion.
Arguing in this way, therefore, they were led to transcend sense-perception, and to disregard it on the ground that one ought to follow reason; and so they assert that the universe is one and immovable. Some of them add that it is infinite, since [15] the limit (if it had one) would be a limit against the void.
There were, then, certain thinkers who, for the reasons we have stated, enunciated views of this kind about the truth . . . Moreover,9 although these opinions appear to follow logically, yet to believe them seems next door to madness when one considers the facts. For indeed no lunatic seems to be so far out of his [20] senses as to suppose that fire and ice are one: it is only between what is right, and what seems right from habit, that some people are mad enough to see no difference.
Leucippus, however, thought he had a theory which harmonized with sense-perception [25] and would not abolish either coming-to-be and passing-away or motion and the multiplicity of things. Making these concessions to the phenomena and conceding to the Monists that there could be no motion without a void, he states that void is not-being, and no part of what is is not-being; for what is in the strict sense of the term is an absolute plenum. This plenum, however, is not one: on the contrary, it [30] is a many infinite in number and invisible owing to the minuteness of their bulk. The many move in the void (for there is a void); and by coming together they produce coming-to-be, while by separating they produce passing-away. Moreover, they act and suffer action wherever they chance to be in contact (for they are not thereby one), and they generate by being put together and becoming intertwined. From the genuinely one, on the other hand, there never could have come-to-be a multiplicity, nor from the genuinely many a one: that is impossible. But just as [325b1] Empedocles and some of the other philosophers say that things suffer action through their pores, so all alteration and all passion take place in this way, breaking-up (i.e. passing-away) being affected by means of the void, and so too [5] growth—solids creeping in to fill the void places.
Empedocles too is practically bound to adopt the same theory as Leucippus. For he must say that there are certain solids which, however, are indivisible—unless there are continuous pores all through the body. But this is impossible; for then there will be nothing solid beside the pores but all of it will be void. It is necessary, therefore, for his contiguous things to be indivisible, while the intervals between [10] them—which he calls pores—must be void. But this is precisely Leucippus’s theory of action and passion.
Such, approximately, are the accounts of the manner in which some things act while others suffer action. And as regards the Atomists, it is not only clear what their explanation is: it is also obvious that it stands in tolerable consistency with the [15] assumptions they employ. But this is less clear in the case of the other thinkers. It is not clear, for instance, how, on the theory of Empedocles, there is to be passing-away as well as alteration. For the primary bodies of the Atomists—the primary constituents of which bodies are composed, and the ultimate elements into which they are dissolved—are indivisible, differing from one another only in figure. In the [20] philosophy of Empedocles, on the other hand, it is evident that all the other bodies down to the elements have their coming-to-be and their passing-away; but it is not clear how the elements themselves, severally in their aggregated masses, come-to-be and pass-away. Nor is it possible for Empedocles to explain how they do so, since he does not assert that Fire too (and similarly every one of his other elements) [25] possesses elementary constituents of itself, as Plato does in the Timaeus10. For Plato differs from Leucippus inasmuch as the indivisibles of Leucippus are solids, while those of Plato are planes, and are characterized by an infinite variety of figures, while the characterizing figures employed by Plato are limited in number—though both hold that the elements are indivisible and are determined by figures. Thus the [30] comings-to-be and the dissociations result from the indivisibles according to Leucippus through the void and through contact (for it is at the point of contact that each of the composite bodies is divisible), but according to Plato in virtue of contact alone, since he denies there is a void.
Now we have discussed indivisible planes in our earlier discussions.11 But with regard to the assumption of indivisible solids, although we must not now enter upon [35] a detailed study of its consequences, let us make a short digression.
They are committed to the view that every indivisible is incapable alike of [326a1] being acted upon (for nothing can suffer action except through the void) and of producing a quality—no indivisible can be either hard or cold. Yet it is surely absurd that an exception is made of the hot—the hot being assigned as peculiar to the spherical figure; for, that being so, its contrary also (the cold) is bound to belong [5] to another of the figures. If, however, these properties (heat and cold) do belong to the indivisibles, it is a further absurdity that they should not possess heaviness and lightness, and hardness and softness. And yet Democritus says that the more any indivisible exceeds, the heavier it is—so that clearly it will also be hotter. But if that [10] is their character, it is impossible they should not be affected by one another: the slightly hot indivisible, e.g., will suffer action from one which far exceeds it in heat. Again, if any indivisible is hard, there must also be one which is soft; but the soft derives its very name from the fact that it suffers a certain action—for soft is that which yields to pressure. But further, not only is it absurd that no property except [15] figure should belong to the indivisibles: it is also absurd that, if other properties do belong to them, one only of these additional properties should attach to each—e.g. that this ind
ivisible should be cold and that indivisible hot. For, on that supposition, their nature would not even be uniform. And it is equally impossible that more than one of these additional properties should belong to the single indivisible. For, being indivisible, it will possess these properties in the same point—so that, if it suffers action by being chilled, it will also, qua chilled, act or suffer action in some other [20] way. And the same line of argument applies to all the other properties too; for the difficulty we have just raised confronts all who advocate indivisibles (whether solids or planes), since their indivisibles cannot become either rarer or denser inasmuch as there is no void in them. It is a further absurdity that there should be small indivisibles, but not large ones. For it is in fact reasonable that larger bodies should [25] be more liable to fracture than the small ones, since they (viz. the large bodies) are easily broken up because they collide with many other bodies. But why should indivisibility as such be the property of small, rather than of large, bodies? Again, is the nature of all those solids uniform, or do they differ from one another—as if, e.g., [30] some of them were fiery, others earthy in their bulk? For if all of them are uniform in nature, what is it that separated one from another? Or why, when they come into contact, do they not coalesce into one, as drops of water run together when drop touches drop (for the two cases are precisely parallel)? On the other hand if they differ, how are they characterized? It is clear, too, that these, rather than the figures, ought to be postulated as principles and causes from which the phenomena result. Moreover, if they differed in nature, they would both act and suffer action on [326b1] coming into reciprocal contact. Again, what is it which sets them moving? For if their mover is other than themselves, they are such as to suffer action. If, on the other hand, each of them sets itself in motion, either it will be divisible (imparting [5] motion here, being moved there), or contrary properties will attach to it in the same respect and its matter will be identical in potentiality as well as numerically identical.
The Complete Works of Aristotle Page 94
