Lecture 7 — Metaphysics differs from all the other sciences

Every science seeks certain principles and causes of each of the knowable objects which comes within its scope. For example, medicine and gymnastics do this, and so does each of the other sciences, whether they are productive or doctrinal. For each of these marks off for itself some genus of things and occupies itself with this as with something that is real and a being, though not as being; but there is a certain other science distinct from these which does this.

And each of the sciences mentioned somehow assumes the quiddity in some genus of things and tries to prove the rest with greater or lesser certainty. Some derive the quiddity from sensory perception, and some by assuming it from some other science. Hence, from such a process of induction, it becomes evident that there is no demonstration of the substance and of its quiddity.

Now, since there is a science of nature, it is evident that it must differ both from the practical and the productive sciences. For in the case of a productive science, the source of motion is in the maker, and not in the thing made, and it is either the art or some kind of potency.

And similarly, in the case of a practical science the motion is not in the thing done, but rather in the agents. But the science of the philosopher of nature is concerned with things that have a source of motion in themselves. It is evident from these considerations, then, that the philosophy of nature must be neither practical nor productive, but speculative, for it must fall in one of these genera.

And since it is necessary that each one of the sciences have some knowledge of the quiddity and must use it as a starting point, we must not fail to consider how the philosophy of nature should define things, and how it should consider the intelligible structure of the substance.

Is it in the same way as the term “snub,” or rather as the term “concave”? For, of these, the notion of snub includes the matter of the object, but that of concave is expressed without matter. For snubness comes into being in a nose, and for this reason its intelligible structure includes matter; for snub is a concave nose. It is evident, then, that the intelligible structure of flesh and of eye and of the other parts of the body must always be given along with matter.

And since there is a science of being as being and as separable, one must consider whether this science should be held to be the same as the philosophy of nature, or rather a science distinct from it.

The philosophy of nature deals with things that have a principle of motion in themselves, and mathematics is speculative and is concerned with things that are permanent but are not separable.

Therefore, there is a science distinct from both of these which treats of what is separable and immovable—that is to say, if there is some such substance, and I mean one which is separable and immovable, as we shall attempt to prove (1071b3–1073a5).

And if there is some such nature among existing things, this will exist somewhere and will be divine, and it will be the primary and highest principle. It is evident, then, that there are three genera of speculative science: the philosophy of nature, mathematics, and theology.

The genus of speculative sciences, then, is the highest, and of these the last mentioned is highest of all. For it is concerned with the noblest of beings, and each science is said to be higher or lower by reason of its proper object.

However, one might raise the question of whether the science of being as being is universal or not. For each of the mathematical sciences deals with some one determinate genus of things, but a universal science is common to all. If, then, natural substances are the primary beings, the philosophy of nature must be the primary science. But if there is another nature and substance which is separable and immovable, the science which treats of this must be different from and prior to the philosophy of nature, and must be universal because it is prior (1059a26).

2247. Having shown with what things this science is concerned, here the Philosopher compares this science with the others. In regard to this, he does three things.

First (1063b36; [2247]), he indicates what is proper to the particular sciences.

Second (1064a10; [2252]), he shows how the particular sciences differ from one another, at now, since there is a science of nature.

Third (1064a28; [2259]), he compares this science with the others, at and since there is a science of being.

In treating the first member of this division, he does two things, insofar as there are two characteristics which he says pertain to the particular sciences.

He accordingly says first (1063b36) that every particular science seeks certain principles and causes of the proper object of knowledge which comes within its scope. He says certain principles and causes because not every science considers every genus of cause.

2248. He gives as examples the science of medicine, whose object is health, and the art of gymnastics, whose object is physical exercise directed to the well-being of the body. The same thing holds true of any of the other sciences, whether they are productive, that is, practical, or doctrinal, that is, theoretical, because each of these particular sciences marks off and takes as its own some determinate genus of being, inasmuch as it confines itself to that genus and deals with it alone. For it is concerned with that genus of being as a certain kind of being, though not as being. But to consider this, namely, being as being, belongs to a science which differs from all of the particular sciences.

2249. And each (1064a4). Second, he gives another characteristic of the particular sciences. He says that each of the above-mentioned particular sciences somehow assumes the quiddity in whatever genus of things is considered. Hence it has been stated at the beginning of the Posterior Analytics that it is necessary to assume both the existence and quiddity of the subject. And having assumed this—that is, the quiddity, which every science uses as a middle term to demonstrate certain things, such as properties and the like—it tries to demonstrate these with greater or lesser certainty, because some sciences have a more certain method of demonstrating, like the mathematical sciences, and others a less certain one, like the natural sciences.

2250. And since he had said that other sciences somehow assume the quiddity, he therefore adds that some sciences derive the quiddity from sensory perception, inasmuch as they acquire a knowledge of a thing’s essence from sensible accidents, and that others derive the quiddity by assuming it from other sciences, as particular sciences from universal ones.

2251. Thus it is evident that, in the particular sciences, there is no demonstration of the substance or the quiddity of a thing. Hence, both of the things with which the particular sciences do not concern themselves—that is, a consideration of the substance and being and the thing’s quiddity—pertain to a universal science.

2252. Now, since there is a science (1064a10). Then he shows how the particular sciences differ from one another.

First (1064a10; [2252]), he shows how the philosophy of nature differs from the productive sciences;

second (1064a19; [2256]), how the mathematical sciences differ from the philosophy of nature, at and since it is necessary.

He accordingly first says (1064a10) that, since there is a particular science of nature, it must be different from the practical, that is, from the sciences which govern activity and the productive sciences. For every practical science is either a science of action or a science of production.

2253. In order to understand this difference, we must consider a distinction which was made above in book 9 (1050a23; [1864]), namely, that to act and to make differ. For “to act” is said properly of an operation which remains in the agent and does not pass over into some external matter—for instance, to understand and to perceive and so on. But to make or produce is said of an operation which passes over into some external matter which is changed—for example, to heat and to cut and the like. Hence there is a science of activity by which we are instructed how to perform correctly those operations which are called actions; moral science is such. But that science by which we make something correctly is a productive science. The art of carpentry and the like belong to this genus.

2254. Now, the philosophy of nature differs from each of these sciences which govern operations. For the productive sciences do not have a principle of motion in the thing made, but in the maker, and this principle is either the art, which is a directive principle, or some potency which is the principle executing the work. Similarly, practical sciences, that is, those governing activity, do not have a principle of motion in that upon which the activity is exercised, but rather in the agents.

2255. But those things that belong to the consideration of the philosophy of nature have their principles of motion in themselves, since nature is a principle of motion in the thing in which it exists. It is evident, then, that the philosophy of nature is a science neither of action nor of production, but is speculative. For the philosophy of nature must fall into one of these genera, namely, active, productive or speculative science. Hence, if it is a science neither of action nor of production, it follows that it must be speculative.

2256. And since (1064a19). Then he shows how the mathematical sciences differ from the philosophy of nature. He says that, since each of the sciences must somehow come to know the quiddity and must use this as a starting point with a view to demonstrating, the sciences must be distinguished on the basis of a different method of defining. Hence, in order to understand how the philosophy of nature differs from the other sciences, we must not neglect to consider the method which the philosophy of nature uses in defining things, and how the definition should be considered in the philosophy of nature—that is, whether a thing should be defined in the way that snub is or in the way that concave is.

2257. Now the definition of snub includes sensible matter, but that of concave does not. For since snubness is found only in a definite sensible matter, because it is found only in a nose, the intelligible structure of snub must therefore include sensible matter, since snub is defined thus: “Snub is a concave nose.” Sensible matter, however, is not included in the definition of concave or curved. Hence, just as sensible matter is included in the definition of snub, so too it must be included in the definition of flesh and of eye and of the other parts of the body. The same holds true of other natural beings.

2258. The difference between the philosophy of nature and mathematics is taken from this, because the philosophy of nature deals with those things whose definitions include sensible matter, whereas mathematics deals with those things whose definitions do not include sensible matter, although they have being in sensible matter.

2259. And since there is (1064a28). Then he compares this science with the other particular sciences, and in regard to this, he does three things.

First (1064a28; [2259]), he compares this science with the different particular sciences in reference to the way in which their objects are separate from matter.

Second (1064b3; [2265]), he compares them from the viewpoint of nobility, at the genus of speculative sciences.

Third (1064b6; [2265]), he compares them from the viewpoint of universality, at however, one might.

He accordingly first says (1064a28) that there is a science of being insofar as it is separable, for it is the office of this science not only to establish the truth about being in common (and this is to establish the truth about being as being) but also to establish the truth about things that are separate from matter in being. Hence it is necessary to consider whether this science whose function is to consider these two things is the same as the philosophy of nature or differs from it.

2260. That it differs from the philosophy of nature he makes clear as follows. The philosophy of nature deals with things that have a principle of motion in themselves; therefore, natural things must have a definite matter, because only that which has matter is moved. But mathematics studies immovable things, for those things whose intelligible structure does not include sensible matter must likewise not have motion in their intelligible structure, since motion is found only in sensible things.

2261. But those things that mathematics considers are not separable from matter and motion in being, but only in their intelligible structure. Hence the science that treats the kind of being that is separable from matter and from motion and is immovable in every respect must be one that differs both from mathematics and from the philosophy of nature.

2262. And here he says, if there is some such substance apart from sensible substances which is immovable in every respect, because the existence of some such substance has not yet been proved, although he intends to prove this.

2263. And if there is some such nature among existing things, namely, one which is separable and immovable, it is necessary that such a nature exist somewhere, that is, that it be attributed to some substance. And whatever has this nature must be something that is divine and the highest of all, because, the simpler and more actual a being is, the nobler it is and the more it is prior and a cause of other things. Thus, it is evident that the science which considers separate beings of this kind should be called the divine science and the science of first principles.

2264. From this he again concludes that there are three genera of speculative science:

the philosophy of nature, which considers things that are movable and have sensible matter in their definition;

mathematics, which considers immovable things that do not have sensible matter in their definition yet exist in sensible matter;

and theology, which considers beings that are entirely separate from matter.

2265. The genus of speculative sciences (1064b3). Next, he compares this science with the others from the viewpoint of nobility. He says that the speculative sciences are the noblest, because, of all the sciences, the speculative seek knowledge for its own sake, whereas the practical seek knowledge for the sake of some work. And among the speculative sciences, there is one that is highest, namely, theology, since a science that deals with more noble beings is itself more noble. For a science is more noble in proportion to the greater nobility of its object.

2266. However, one might (1064b6). Then he compares this science with the others from the viewpoint of universality. He says that one might raise the question of whether or not the science that deals with separate beings must be held to be a universal science of being as being, and that it must be such he shows by a process of division.

2267. For it is evident that the foregoing sciences which deal with operations are not universal sciences, and he therefore omits them. In the case of the speculative sciences, it is evident that every mathematical science is concerned with some one determinate genus of things. But a universal science deals with all things in common. No mathematical science, then, can be the one which treats all beings in common. Regarding the philosophy of nature, it is evident that, if natural substances, which are perceptible and movable, are the primary beings, the philosophy of nature must be the primary science; for the order of the sciences corresponds with that of their subjects, as has been stated already (1064b3; [2265]). But if there is a different nature and substance over and above natural substances which is separable and immovable, there must be a science which differs from the philosophy of nature and is prior to it. And because it is first, it must be universal, for it is the same science which treats of primary beings and of what is universal, since the primary beings are the principles of the others.