LECTURE 1 (184 a 9-b 14)

THE MATTER AND THE SUBJECT OF NATURAL SCIENCE AND OF THIS BOOK. WE MUST PROCEED FROM THE MORE UNIVERSAL PRINCIPLES WHICH ARE BETTER KNOWN TO US

1. Because this book, The Physics, upon which we intend to comment here, is the first book of natural science, it is necessary in the beginning to decide what is the matter and the subject of natural science.

             Since every science is in the intellect, it should be understood that something is rendered intelligible in act insofar as it is in some way abstracted from matter. And inasmuch as things are differently related to matter they pertain to different sciences.

             Furthermore, since every science is established through demonstration, and since the definition is the middle term in a demonstration, it is necessary that sciences be distinguished according to the diverse modes of definition.

             2. It must be understood, therefore, that there are some things whose existence depends upon matter, and which cannot be defined without matter. Further there are other things which, even though they cannot exist except in sensible matter, have no sensible matter in their definitions. And these differ from each other as the curved differs from the snub. For the snub exists in sensible matter, and it is necessary that sensible matter fall in its definition, for the snub is a curved nose. And the same is true of all natural things, such as man and stone. But sensible matter does not fall in the definition of the curved, even though the curved cannot exist except in sensible matter. And this is true of all the mathematicals, such as numbers, magnitudes and figures. Then, there are still other things which do not depend upon matter either according to their existence or according to their definitions. And this is either because they never exist in matter, such as God and the other separated substances, or because they do not universally exist in matter, such as substance, potency and act, and being itself.

             3. Now metaphysics deals with things of this latter sort. Whereas mathematics deals with those things which depend upon sensible matter for their existence but not for their definitions. And natural science, which is called physics, deals with those things which depend upon matter not only for their existence, but also for their definition.

             And because everything which has matter is mobile, it follows that mobile being is the subject of natural philosophy. For natural philosophy is about natural things, and natural things are those whose principle is nature. But nature is a principle of motion and rest in that in which it is. Therefore natural science deals with those things which have in them a principle of motion.

             4. Furthermore those things which are consequent upon something common must be treated first and separately. Otherwise it becomes necessary to repeat such things many times while discussing each instance of that which is common. Therefore it was necessary that one book in natural science be set forth in which those things which are consequent upon mobile being in common are treated; just as first philosophy, in which those things which are common to being insofar as it is being, is set forth for all the sciences.

             This, then, is the book, The Physics, which is also called On Physics, or Of the Natural to be Heard, because it was handed down to hearers by way of instruction. And its subject is mobile being simply.

             I do not, however, say mobile body, because the fact that every mobile being is a body is proven in this book, and no science proves its own subject. And thus in the very beginning of the De Caelo, which follows this book, we begin with the notion of body.

             Moreover, after The Physics there are other books of natural science in which the species of motion are treated. Thus in the De Caelo we treat the mobile according to local motion, which is the first species of motion. In the De Generatione, we treat of motion to form and of the first mobile things, i.e., the elements, with respect to the common aspects of their changes. Their special changes are considered in the book Meteororum. In the book, De Mineralibus, we consider the mobile mixed bodies which are non-living. Living bodies are considered in the book, De Anima and the books which follow it.

             5. To this book, then, the Philosopher writes a preface in which he shows the order of procedure in natural science.

             In this preface he does two things. First he shows that it is necessary to begin with a consideration of principles. Secondly, where he says, 'The natural way of doing this . . .' (184 a 16), he shows that among principles, it is necessary to begin with the more universal principles.

             First he gives the following argument. In all sciences of which there are principles or causes or elements, understanding and science proceed from a knowledge of the principles, causes and elements. But the science which is about nature has principles, elements and causes. Therefore it is necessary in it to begin with a determination of principles.

             When he says 'to understand' he has reference to definitions, and when he says 'to have science' he has reference to demonstrations. For as demonstrations are from causes, so also are definitions, since a complete definition is a demonstration differing only by position, as is said in Posterior Analytics, I.

             When, however, he speaks of principles or causes or elements, he does not intend to signify the same thing by each. For cause is wider in meaning than element. An element is a first component of a thing and is in it [i.e., in the composed], as is said in Metaphysics, V. Thus the letters, but not the syllables, are the elements of speech. But those things are called causes upon which things depend for their existence or their coming to be. Whence even that which is outside the thing, or that which is in it, though the thing is not first composed of it, can be called a cause. But it cannot be called an element. And thirdly principle implies a certain order in any progression. Whence something can be a principle which is not a cause, as that from which motion begins is a principle of motion, but is not a cause, and a point is a principle of a line but not a cause.

             Therefore, by principle he seems to mean moving causes and agents in which, more than in others, there is found an order of some progression. By causes he seems to mean formal and final causes upon which things most of all depend for their existence and their coming to be. By elements he means properly the first material causes.

             Moreover he uses these terms disjunctively and not copulatively in order to point out that not every science demonstrates through all the causes. For mathematics demonstrates only through the formal cause. Metaphysics demonstrates through the formal and final causes principally but also through the agent. Natural science, however, demonstrates through all the causes.

             He then proves from common opinion the first proposition of his argument. This is also proven in the Posterior Analytics. For a man thinks that he knows something when he knows all its causes from the first to the last. The meaning here of causes, principles, and elements is exactly the same as we have explained above, even though the Commentator disagrees. Furthermore Aristotle says, '. . . as far as its simplest elements' (184 a 14), because that which is last in knowledge is matter. For matter is for the sake of form, and form is from the agent for the sake of the end, unless it itself is the end. For example, we say that a saw has teeth in order to cut, and these teeth ought to be made of iron so they will be apt for cutting.

             6. Next where he says, 'The natural way of doing this . . .' (184 a 16), he shows that among principles it is necessary to treat the more universal ones first. And he shows this first by means of an argument, and secondly, by an example, where he says, '. . . for it is a whole . . .' (184 a 25).

             First he gives the following argument. It is natural for us to proceed in knowing from those things which are better known to us to those which are better known by nature. But the things which are better known to us are confused, such as the universals. Therefore it is necessary for us to proceed from universals to singulars.

             7. For purposes of clarifying the first proposition he makes the point that things which are better known to us and things which are better known according to nature are not the same. Rather those things which are better known according to nature are less known to us. And because the natural way or order of learning is that we should come to that which is unknown by us from that which is known by us, it is necessary for us to arrive at the better known in nature from the better known to us.

             It must be noted, however, that that which is known by nature and that which is known simply mean the same. Those things are better known simply which are in themselves better known. But those things are better known in themselves which have more being, because each thing is knowable insofar as it is being. However, those beings are greater which are greater in act. Whence these are the most knowable by nature.

             For us, however, the converse is true because we proceed in understanding from potency to act. Our knowledge begins from sensible things which are material and intelligible in potency. Whence these things are known by us before the separated substances, which are better known according to nature, as is clear in Metaphysics, II.

             He does not, therefore, say known by nature as if nature knew these things, but because they are better known in themselves and according to their proper natures. And he says better known and more certain, because in the sciences not just any kind of knowledge is sought, but a certain knowledge.

             Next in order to understand the second proposition, it must be known that those things are here called 'confused' which contain in themselves something potential and indistinct. And because to know something indistinctly is a mean between pure potency and perfect act, so it is that while our intellect proceeds from potency to act, it knows the confused before it knows the distinct. But it has complete science in act when it arrives, through resolution, at a distinct knowledge of the principles and elements. And this is the reason why the confused is known by us before the distinct.

             That universals are confused is clear. For universals contain in themselves their species in potency. And whoever knows something in the universal knows it indistinctly. The knowledge, however, becomes distinct when each of the things which are contained in potency in the universal is known in act. For he who knows animal does not know the rational except in potency. Thus knowing something in potency is prior to knowing it in act. Therefore, according to this order of learning, in which we proceed from potency to act, we know animal before we know man.

             8. It would seem, however, that this is contrary to what the Philosopher says in Posterior Analytics, I, namely, that singulars are better known to us, whereas the universals are better known by nature or simply.

             But it must be understood that there he takes as singulars the individual sensible things themselves, which are better known to us because the knowledge of sense, which is of singulars, does precede in us the knowledge of the intellect, which is of universals. And because intellectual knowledge is more perfect, and because the universals are intelligible in act, whereas the singulars are not (since they are material), the universals are better known simply and according to nature.

             Here, however, by singulars he means not the individuals themselves, but the species. And these are better known by nature, existing more perfectly, as it were, and being known with a distinct knowledge. But the genera are known by us first, being known, as it were, confusedly and in potency.

             It should be known, however, that the Commentator explains this passage in another way. He says that in the passage beginning, 'The natural way of doing this . . .' (184 a 16), the Philosopher wishes to explain the method of demonstration of this science, namely, that this science demonstrates through the effect and what is posterior according to nature. Hence what is said here is to be understood of the progression in demonstration and not of the progression in determination. Then in the passage where Aristotle says, 'Now what is plain to us . . .' (184 a 22), he intends to make clear (according to the Commentator) what things are better known to us and what is better known by nature, i.e., things which are composed of the simple, understanding 'confused' to mean 'composed'. Finally, then, he concludes, as if to a corollary, that we must proceed from the more universal to the less universal.

             It is clear that his explanation is not suitable, because he does not join the whole passage to one intention. Moreover the Philosopher does not intend to set forth the mode of demonstration of this science here, because he will do this in Book II according to his order of treatment. Furthermore, the confused should not be taken to mean composed, but rather to mean indistinct. For nothing could be concluded from such universals because genera are not composed of species.

             9. Next, where he says, '. . . for it is a whole . . .' (184 a 25), he clarifies his position with three examples. The first of these is taken from the integral sensible whole. He says that since the sensible whole is better known to the sense, then, the intelligible whole is also better known to the intellect. But the universal is a sort of intelligible whole, because it comprehends many as parts, namely, its inferiors. Therefore the universal is better known to us intellectually.

             But it would seem that this proof is not effective, because he uses whole and part and comprehension equivocally.

             However it must be said that the integral whole and the universal agree in that each is confused and indistinct. For just as he who apprehends a genus does not apprehend the species distinctly, but in potency only, so also he who apprehends a house does not yet distinguish its parts. Whence it is that a whole is first known to us as confused. This applies to both of these wholes. However, to be composed is not common to each whole. Whence it is clear that Aristotle significantly said 'confused' above and not 'composed'.

             10. Next where he says, 'Much the same thing . . .' (184 b 9), he gives another example taken from the integral intelligible whole.

             For that which is defined is related to the things defining it as a kind of integral whole, insofar as the things defining it are in act in that which is defined. But he who apprehends a name, for example, man or circle, does not at once distinguish the defining principles. Whence it is that the name is, as it were, a sort of whole and is indistinct, whereas the definition divides into singulars, i.e., distinctly sets forth the principles of that which is defined.

             This, however, seems to be contrary to what he said above. For the things which define would seem to be more universal, and these, he said, were first known by us. Furthermore, if that which is defined were better known to us than the things which define, we would not grasp that which is defined through the definition, for we grasp nothing except through that which is better known to us.

             But it must be said that the things which define are in themselves known to us before that which is defined, but we know the thing which is defined before we know that these are the things which define it. Thus we know animal and rational before we know man. But man is known confusedly before we know that animal and rational are the things which define man.

             11. Next where he says, 'Similarly a child . . .' (184 b 11), he gives the third example taken from the more universal sensible. For as the more universal intelligible is first known to us intellectually, for example, animal is known before man, so the more common sensible is first known to us according to sense, for example, we know this animal before we know this man.

             And I say first according to sense both with reference to place and with reference to time. This is true according to place because, when someone is seen at a distance, we perceive him to be a body before we perceive that he is an animal, and animal before we perceive him to be a man, and finally we perceive that he is Socrates. And in the same way with reference to time, a boy apprehends this individual as some man before he apprehends this man, Plato, who is his father. And this is what he says: children at first call all men fathers and all women mothers, but later they determine, that is, they know each determinately.

             From this it is clearly shown that we know a thing confusedly before we know it distinctly.