The following account will make it plain that there is an absolutely light and an absolutely heavy body. (15) And by absolutely light I mean one which of its own nature always moves upward, by absolutely heavy one which of its own nature always moves downward, if no obstacle is in the way. There are, I say, these two kinds of body, and it is not the case, as some9 maintain, that all bodies have weight. Different views are in fact agreed that there is a heavy body, (20) which moves uniformly towards the centre. But there is also similarly a light body. For we see with our eyes, as we said before,10 that earthy things sink to the bottom of all things and move towards the centre. But the centre is a fixed point. If therefore there is some body which rises to the surface of all things—and we observe fire to move upward even in air itself, while the air remains at rest—clearly this body is moving towards the extremity. It cannot then have any weight. If it had, (25) there would be another body in which it sank: and if that had weight, there would be yet another which moved to the extremity and thus rose to the surface of all moving things. In fact, however, we have no evidence of such a body. Fire, then, has no weight. Neither has earth any lightness, since it sinks to the bottom of all things, and that which sinks moves to the centre. That there is a centre towards which the motion of heavy things, (30) and away from which that of light things is directed, is manifest in many ways. First, because no movement can continue to infinity. For what cannot be can no more come-to-be than be, and movement is a coming-to-be in one place from another. Secondly, like the upward movement of fire, (35) the downward movement of earth and all heavy things makes equal angles on every side with the earth’s surface: it must therefore be directed towards the centre. [312a] Whether it is really the centre of the earth and not rather that of the whole to which it moves, may be left to another inquiry, since these are coincident.11 But since that which sinks to the bottom of all things moves to the centre, necessarily that which rises to the surface moves to the extremity of the region in which the movement of these bodies takes place. (5) For the centre is opposed as contrary to the extremity, as that which sinks is opposed to that which rises to the surface. This also gives a reasonable ground for the duality of heavy and light in the spatial duality centre and extremity. Now there is also the intermediate region to which each name is given in opposition to the other extreme. For that which is intermediate between the two is in a sense both extremity and centre. (10) For this reason there is another heavy and light; namely, water and air. But in our view the continent pertains to form and the contained to matter: and this distinction is present in every genus.12 Alike in the sphere of quality and in that of quantity there is that which corresponds rather to form and that which corresponds to matter. (15) In the same way, among spatial distinctions, the above belongs to the determinate, the below to matter. The same holds, consequently, also of the matter itself of that which is heavy and light: as potentially possessing the one character, it is matter for the heavy, and as potentially possessing the other, for the light. It is the same matter, but its being is different, as that which is receptive of disease is the same as that which is receptive of health, (20) though in being different from it, and therefore diseasedness is different from healthiness.
5 A thing then which has the one kind of matter is light and always moves upward, while a thing which has the opposite matter is heavy and always moves downward. Bodies composed of kinds of matter different from these but having relatively to each other the character which these have absolutely, possess both the upward and the downward motion. (25) Hence air and water each have both lightness and weight, and water sinks to the bottom of all things except earth, while air rises to the surface of all things except fire. But since there is one body only which rises to the surface of all things and one only which sinks to the bottom of all things, there must needs be two other bodies which sink in some bodies and rise to the surface of others. (30) The kinds of matter, then, must be as numerous as these bodies, i. e. four, but though they are four there must be a common matter of all—particularly if they pass into one another—which in each is in being different. [312b] There is no reason why there should not be one or more intermediates between the contraries, as in the case of colour; for ‘intermediate’ and ‘mean’ are capable of more than one application.
Now in its own place every body endowed with both weight and lightness has weight—whereas earth has weight everywhere—but they only have lightness among bodies to whose surface they rise. (5) Hence when a support is withdrawn such a body moves downward until it reaches the body next below it, air to the place of water and water to that of earth. But if the fire above air is removed, it will not move upward to the place of fire, except by constraint; and in that way water also may be drawn up, (10) when the upward movement of air which has had a common surface with it is swift enough to overpower the downward impulse of the water. Nor does water move upward to the place of air, except in the manner just described. Earth is not so affected at all, because a common surface is not possible to it. Hence water is drawn up into the vessel to which fire is applied, but not earth. As earth fails to move upward, (15) so fire fails to move downward when air is withdrawn from beneath it: for fire has no weight even in its own place, as earth has no lightness. The other two move downward when the body beneath is withdrawn because, while the absolutely heavy is that which sinks to the bottom of all things, the relatively heavy sinks to its own place or to the surface of the body in which it rises, since it is similar in matter to it.
It is plain that one must suppose as many distinct species of matter as there are bodies. (20) For if, first, there is a single matter of all things, as, for instance, the void or the plenum or extension or the triangles, either all things will move upward or all things will move downward, and the second motion will be abolished. And so, either there will be no absolutely light body, if superiority of weight is due to superior size or number of the constituent bodies or to the fullness of the body: but the contrary is a matter of observation, (25) and it has been shown that the downward and upward movements are equally constant and universal: or, if the matter in question is the void or something similar, which moves uniformly upward, there will be nothing to move uniformly downward. Further, it will follow that the intermediate bodies move downward in some cases quicker than earth: for air in sufficiently large quantity will contain a larger number of triangles or solids or particles. (30) It is, however, manifest that no portion of air whatever moves downward.13 And the same reasoning applies to lightness, if that is supposed to depend on superiority of quantity of matter.14 But if, secondly, the kinds of matter are two, it will be difficult to make the intermediate bodies behave as air and water behave. [313a] Suppose, for example, that the two asserted are void and plenum. Fire, then, as moving upward, will be void, earth, as moving downward, plenum; and in air, it will be said, fire preponderates, in water, earth. There will then be a quantity of water containing more fire than a little air, and a large amount of air will contain more earth than a little water: consequently we shall have to say that air in a certain quantity moves downward more quickly than a little water. (5) But such a thing has never been observed anywhere. Necessarily, then, as fire goes up because it has something, e. g. void, which other things do not have, and earth goes downward because it has plenum, so air goes to its own place above water because it has something else, (10) and water goes downward because of some special kind of body. But if the two bodies15 are one matter, or two matters both present in each, there will be a certain quantity of each at which water will excel a little air in the upward movement and air excel water in the downward movement, as we have already often said.
6 The shape of bodies will not account for their moving upward or downward in general, (15) though it will account for their moving faster or slower. The reasons for this are not difficult to see. For the problem thus raised is why a flat piece of iron or lead floats upon water, while smaller and less heavy things, so long as they are round or long—a needle,
for instance—sink down; and sometimes a thing floats because it is small, as with gold dust and the various earthy and dusty materials which throng the air. (20) With regard to these questions, it is wrong to accept the explanation offered by Democritus. He says that the warm bodies moving up out of the water hold up heavy bodies which are broad, while the narrow ones fall through, because the bodies which offer this resistance are not numerous. [313b] But this would be even more likely to happen in air—an objection which he himself raises. His reply to the objection is feeble. In the air, he says, the ‘drive’ (meaning by drive the movement of the upward moving bodies) is not uniform in direction. (5) But since some continua are easily divided and others less easily, and things which produce division differ similarly in the ease with which they produce it, the explanation must be found in this fact. It is the easily bounded, in proportion as it is easily bounded, which is easily divided; and air is more so than water, (10) water than earth. Further, the smaller the quantity in each kind, the more easily it is divided and disrupted. Thus the reason why broad things keep their place is because they cover so wide a surface and the greater quantity is less easily disrupted. (15) Bodies of the opposite shape sink down because they occupy so little of the surface, which is therefore easily parted. And these considerations apply with far greater force to air, since it is so much more easily divided than water. But since there are two factors, the force responsible for the downward motion of the heavy body and the disruption-resisting force of the continuous surface, there must be some ratio between the two. For in proportion as the force applied by the heavy thing towards disruption and division exceeds that which resides in the continuum, (20) the quicker will it force its way down; only if the force of the heavy thing is the weaker, will it ride upon the surface.
We have now finished our examination of the heavy and the light and of the phenomena connected with them.
* * *
1 The digression is directed against Plato, Tim. 62 E; but the view was held by others besides Timaeus.
2 63 C.
3 The atomists, Democritus and Leucippus.
4 For, since the planes have no weight, their number cannot affect the weight of a body.
5 Plato, in the Timaeus.
6 Phys. vii. 1. 241b 24; viii. 4. 254b 7.
7 i. e. because there are distinct species of light and heavy.
8 Above, 309b 20: if they would only give an account of the simple bodies, their questions as to the composite would answer themselves.
9 This view is maintained in its most unqualified form by those (atomists, probably) who distinguish the four elements by the size of their particles (Cf. C. 2. 310a 9).
10 Above, 311a 20.
11 The question is discussed in ii. 14. 296b 9.
12 i. e. in every category.
13 sc. in earth.
14 On the somewhat absurd theory that the universal ‘matter’ is void or absolute lightness.
15 viz. air and water.
De Generatione et Corruptione
Translated by Harold H. Joachim
CONTENTS
BOOK I
CHAPTERS 1–5. Coming-to-be and passing-away are distinguished from ‘alteration’ and from growth and diminution.
CHAPTER
1. Are coming-to-be and passing-away distinct from ‘alteration’? It is clear that, amongst the ancient philosophers, the monists are logically bound to identify, and the pluralists to distinguish, these changes. Hence both Anaxagoras and Empedocles (who are pluralists) are inconsistent in their statements on this subject. Empedocles, it must be added, is inconsistent and obscure in many other respects as well.
2. There are no indivisible magnitudes. Nevertheless, coming-to-be and passing-away may well occur and be distinct from ‘alteration’. For coming-to-be is not effected by the ‘association’ of discrete constituents, nor passing-away by their ‘dissociation’; and ‘change in what is continuous’ is not always ‘alteration’.
3. Coming-to-be and passing-away (in the strict or ‘unqualified’ sense of the terms) are in fact always occurring in Nature. Their ceaseless occurrence is made possible by the character of Matter (materia prima).
4. ‘Alteration’ is change of quality. It is thus essentially distinct from coming-to-be and passing-away, which are changes of substance.
5. Definition and explanation of growth and diminution.
CHAPTERS 6–10. What comes-to-be is formed out of certain material constituents, by their ‘combination’. Combination implies ‘action and passion’, which in turn imply ‘contact’.
6. Definition and explanation of ‘contact’.
7. Agent and patient are neither absolutely identical with, nor sheerly other than, one another. They must be contrasted species of the same genus, opposed formations of the same matter.
8. Bodies do not consist of indivisible solids with void interspaces, as the Atomists maintain: nor are there ‘pores’ or empty channels running through them, as Empedocles supposes. Neither of these theories could account for ‘action-passion’.
9. The true explanation of ‘action-passion’ depends (a) upon the distinction between a body’s actual and potential possession of a quality, and (b) upon the fact that potential possession (i. e. ‘susceptibility’) may vary in intensity or degree in different parts of the body.
10. What ‘combination’ is, and how it can take place.
BOOK II
CHAPTERS 1–8. The material constituents of all that comes-to-be and passes-away are the so-called ‘elements’, i. e., the ‘simple’ bodies. What these are, how they are transformed into one another, and how they ‘combine’.
CHAPTER
1. Earth, Air, Fire, and Water are not really ‘elements’ of body, but ‘simple’ bodies. The ‘elements’ of body are ‘primary matter’ and certain ‘contrarieties’.
2. The ‘contrarieties’ in question are ‘the hot and the cold’ and ‘the dry and the moist’.
3. These four ‘elementary qualities’ (hot, cold, dry, moist) are diversely coupled so as to constitute four ‘simple’ bodies analogous to, but purer than, Earth, Air, Fire, and Water.
4. The four ‘simple’ bodies undergo reciprocal transformation in various manners.
5. Restatement and confirmation of the preceding doctrine.
6. Empedocles maintains that his four ‘elements’ cannot be transformed into one another. How then can they be ‘equal’ (i. e. comparable) as he asserts? His whole theory, indeed, is thoroughly unsatisfactory. In particular, he entirely fails to explain how compounds (e. g. bone or flesh) come-to-be out of his ‘elements’.
7. How the ‘simple’ bodies combine to form compounds.
8. Every compound body requires all four ‘simple’ bodies as its constituents.
CHAPTERS 9–10. The causes of coming-to-be and passing-away.
9. Material, formal, and final causes of coming-to-be and passing-away. The failure of earlier theories—e. g. of the ‘materialist’ theory and of the theory advanced by Socrates in the Phaedo—must be ascribed to inadequate recognition of the efficient cause.
10. The sun’s annual movement in the ecliptic or zodiac circle is the efficient cause of coming-to-be and passing-away. It explains the occurrence of these changes and their ceaseless alternation.
Appendix.
11. In what sense, and under what conditions, the things which come-to-be are ‘necessary’. Absolute necessity characterizes every sequence of transformations which is cyclical.
DE GENERATIONE ET CORRUPTIONE
(On Generation and Corruption)
BOOK I
1 [314a] Our next task is to study coming-to-be and passing-away. We are to distinguish the causes, and to state the definitions, of these processes considered in general—as changes predicable uniformly of all the things that come-to-be and pass-away by nature. Further, we are to study growth and ‘alteration’. We must inquire what each of them is; and whether ‘alteration’ is to be identified with coming-to-b
e, (5) or whether to these different names there correspond two separate processes with distinct natures.
On this question, indeed, the early philosophers are divided. Some of them assert that the so-called ‘unqualified coming-to-be’ is ‘alteration’, while others maintain that ‘alteration’ and coming-to-be are distinct. For those who say that the universe is one something (i. e. those who generate all things out of one thing) are bound to assert that coming-to-be is ‘alteration’, (10) and that whatever ‘comes-to-be’ in the proper sense of the term is ‘being altered’: but those who make the matter of things more than one must distinguish coming-to-be from ‘alteration’. To this latter class belong Empedocles, Anaxagoras, and Leucippus. And yet Anaxagoras himself failed to understand his own utterance. He says, at all events, that coming-to-be and passing-away are the same as ‘being altered’: yet, (15) in common with other thinkers, he affirms that the elements are many. Thus Empedocles holds that the corporeal elements are four, while all the elements—including those which initiate movement—are six in number; whereas Anaxagoras agrees with Leucippus and Democritus that the elements are infinite.
The Basic Works of Aristotle (Modern Library Classics) Page 66