Κατηγορίες αρχείου: Physics
Let us speak about generation and alteration and what they are different in; for we say that these changes are different from one another. Since, then, one thing is what is subject to something and another that property which is said (predicated) of the former, and it happens that each of them can change, we speak of alteration when the underlying thing, though perceptible and persistent, changes in virtue of its properties, whether these are contraries or intermediates. For example, a body is well and then ill, though it remains the same body; and a copper is now round and at another time with angles, but remains the same copper.
According to Aristotle, the term “fulfilment” (entelexeia) signifies the agency and completion; for it is composed of one (en), complete (teleion), and having (exein), since each one thing is said to be in fulfilment when it has its own completion. Of each case the fulfilment is twofold: in one sense, when the actual thing is already done and its whole potentiality has been thrown away, in another, when it has been changed by the potency and is altering in accordance with it and coming to receive its form, as with the copper that is potentially a statue. For we regard it to be a case of fulfilment both when it becomes a statue by the sculptor and forms into such and such a shape, and when it is already a statue and has received its complete form. But the latter fulfilment is exempt from the presence of the potency by virtue of which it was capable of becoming a statue — for it is already a statue and is no more in potentiality. That is why this fulfilment is not the completion of the potency (for how could it be, if it passes away?), but that of the actual thing where the potency was based in. On the other hand, the former mentioned fulfilment, by virtue of which the copper was coming to be a statue, still maintains its potentiality. And this fulfilment is an incomplete agency (for it proceeds towards the form and the most spoken of and unqualified fulfilment) — and for that reason is called first fulfilment — whereas the other is a complete agency; for the thing changed rests within it when it comes to be whatever is the case, and relieves itself entirely of being in potentiality.
That of which nothing is left outside, is complete and whole; for thus we define the whole, as that of which nothing is absent, e.g. a whole man or a whole box. And what holds for each particular the same holds too for the whole in its most proper sense, as it is the universe whose nothing is outside; but that of which there holds an absence outside, is not all, whatever may be absent. The whole and the complete are either completely the same or very close in regard to their nature. And nothing is complete unless it has an end; and the end is a limit.
Given that each kind of being is divided into that which is in actuality, and into that which is in potentiality, the actualization of that which is in potentiality, in so far it is such, is change, e.g. the actualization of that which is capable of altering, in so far it is such as to be capable of altering, is alteration, of that which is capable of increasing and its opposite, that which is capable of decreasing (there is no common name for both of them), increase and decrease, of that which is capable of coming to be and passing away, coming to be and passing away, of that which is capable of being carried along, locomotion. That this is change is clear from this. For when that which is capable of building, in so far it is said to be such, is in actuality, it is being built, and this is building; and similarly with learning and doctoring and rolling and jumping and maturing and ageing.
Something is said to be “in vain”, when the end for the sake of which it comes to be does not occur, e.g. if walking takes place for the loosening of the bowels; if this does not follow after that, we say that we have walked in vain and that the walking was vain, as “in vain” means this: something which is by nature for the sake of something else and fail to accomplish the end for the sake of which it was for. So if this is what is in vain, the automatic, therefore, is well derived from that which is itself in vain. For we say that the stone automatically became such as to be for someone to sit on, as indeed the automatic is the cause for that; for “to be into the proper place” was the natural end of the stone’s moving downwards, yet another concurrent end has been followed to that, which is to become such as to sit on. Since, then, its moving downwards has become by virtue of concurrence the cause of such a shape, it is called automatic, as becoming itself in vain with regard to the concurrent happening.
Since everything which comes to be comes to be either out of something which is or out of something which is not, and it is impossible for both of them to be the case, in that it cannot come to be out of what is (because it is already) nor can it come out of what is not (since it cannot come out of something which is not pre-existent), some people thought either that nothing comes to be or passes away, or that “what is not” is. We, on the other hand, will resolve their difficulty, starting, first, with the various ways in which “what is” is spoken of.
Causes are spoken of in a number of ways. In one way, then, that out of which a thing comes about and which is immanent, is called cause, e.g. the bronze of the statue, the stone of the house, and the genera of these. In another, the form and the exemplar (archetype) are called causes; that is, the statement of the essence of a thing (the definition), and its genera; for example, for an octave, the ratio 2 to 1, and in general the number and the parts in its definition. Again, whence the first origin of a change or of a standstill; for example, the man who gave advice is a cause, the father is cause of the child, and in general what makes of what is made and what causes change of what is changed. Moreover, the end (purpose); that is, the final cause, e.g. health is the cause of walking. For why does one walk? We say ‘τo be healthy’, and in speaking thus we think we have given the cause.
Of things some are (exist) by nature, others from other causes (e.g. art, chance, etc.). By nature are the animals and their parts, the plants and the simple bodies, i.e. earth, fire, air, water – for we say that these and the like exist by nature. All these seem to be different from those which are not constituted by nature. For each of them has within itself a principle of motion and of standstill, some in virtue of place, others in virtue of increase and of decrease, and others in virtue of alteration. On the other hand, a bed or a cloak, or anything else of that sort, in as the above attributes are referred to them, and they exist by art, have no innate impulse to change, but in so far as they happen to be composed of stone or of earth, or compounded of these, they do have, and to that extent, as nature is a certain principle or cause for motion and for stillness within that to which it belongs, primarily, just by itself and not accidentally.