LESSON 1

The Method of Investigating Being as Being. How

This Science Differs from the Other Sciences

  Chapter 1: 1025b 3-1026a 32

             532. The principles and causes of beings are the object of our search, and it is evident that [we must investigate the principles and causes of beings] as beings. For there is a cause of health and of its recovery; and there are also principles and elements and causes of the objects of mathematics; and in general every intellectual science, to whatever degree it participates in intellect, deals with principles and causes: either with those which are more certain or with those which are simpler.

             533. But all these sciences single out some one thing, or some particular class, and confine their investigations to this, but they do not deal with being in an unqualified sense, or as being. Nor do they make any mention of the whatness itself of things. But proceeding from this, some making it evident by means of the senses, and others taking it by assuming it [from some other science], they demonstrate with greater necessity or more weakly the essential attributes of the class of things with which they deal. For this reason it is evident that there is no demonstration of a thing's substance or whatness from such an inductive method, but there is another method of making it known. And similarly they say nothing about the existence or non-existence of the class of things with which they deal, because it belongs to the same science to show what a thing is and whether it exists.

             534. And since the philosophy of nature is concerned with some class of being (for it deals with that kind of substance in which there is a principle of motion and rest), it is evident that it is neither a practical nor a productive science. For the principle of productive sciences is in the maker, whether it be intellect or art or some kind of power; but the principle of practical sciences is prohaeresis in the agent, for the object of action and that of choice are the same. Thus if every science is either practical, productive or theoretical, the philosophy of nature will be a theoretical science. But it will be theoretical of that kind of being which is subject to motion, and of that kind of substance which is inseparable from matter in its intelligible structure for the most part only.

             535. Now the essence and the conceptual expression of the way in which a thing exists must not remain unknown, because without this our investigation will be unfruitful. And regarding things defined, or their whatness, some are like snub and others like concave. And these differ, because snub is conceived with sensible matter (for snub is a concave nose), whereas concave is conceived without sensible matter. But all physical things are spoken of in a way similar to snub, for example, nose, eye, face, flesh, bone and animal in general; leaf, root, bark and plant in general (for the definition of none of these is without motion but always includes matter). Thus it is clear how we must investigate and define the essence in the case of physical things, and why it also belongs to the natural philosopher to speculate about one kind of soul--that which does not exist without matter. From these facts, then, it is evident that the philosophy of nature is a theoretical science.

             536. But mathematics is also a theoretical science, although it is not yet evident whether it deals with things which are immobile and separable from matter. However, it is evident that mathematics speculates about things insofar as they are immobile and insofar as they are separable from matter.

             537. Now if there is something which is immobile, eternal and separable from matter, evidently a knowledge of it belongs to a theoretical science. However, it does not belong to the philosophy of nature (for this science deals with certain mobile things), or to mathematics, but to a science prior to both. For the philosophy of nature deals with things which are inseparable from matter but not immobile. And some mathematical sciences deal with things which are immobile, but presumably do not exist separately, but are present as it were in matter. First philosophy, however, deals with things which are both separable from matter and immobile. Now common causes must be eternal, and especially these; since they are the causes of the sensible things visible to us.

             538. Hence there will be three theoretical philosophies: mathematics, the philosophy of nature, and theology.

             539. For it is obvious that, if the divine exists anywhere, it exists in this kind of nature.

             540. And the most honorable of the sciences must deal with the most honorable class of things. Therefore the theoretical sciences are more desirable than the other sciences.

             541. But someone will raise the question whether first philosophy is universal or deals with some particular class, i.e., one kind of reality; for not even in the mathematical sciences is the method the same, because both geometry and astronomy deal with a particular kind of nature, whereas the first science is universally common to all.

             542. Therefore, if there is no substance other than those which exist in the way that natural substances do, the philosophy of nature will be the first science; but if there is an immobile substance, this substance will be prior, and [the science which investigates it will be] first philosophy, and will be universal in this way. And because it will be first and about being, it will be the function of this science to investigate both what being is and what the attributes are which belong to it as being.

COMMENTARY

             1144. Having shown in Book IV (297:C 535) of this work that this science considers being and unity and those attributes which belong to being as such, and that all of these are used in several senses; and having distinguished the number of these in Book V (423:C 843; 435:C 885) of this work, here the Philosopher begins to establish the truth about being and those attributes which belong to being.

             This part is divided into two sections. In the first (532:C 1145) he explains the method by which this science should establish what is true about being. In the second (560:C 1247) he begins to settle the issue about being. He does this at the beginning of Book VII ("The term being is used in many senses").

             The first part is divided into two sections. In the first he explains the method of treating beings, which is proper to this science, by showing how it differs from the other sciences. In the second (543:C 1171) he excludes certain senses of being from the investigation of this science, namely, those senses which are not the chief concern of this science ("Being in an unqualified sense").

             The first part is again divided into two sections. In the first he shows how this science differs from the others because it considers the principles of being as being. In the second (534:C 1152) he shows how this science differs from the others in its method of treating principles of this kind ("And since the philosophy of nature"). In regard to the first he does two things.

             1145. First (532), he shows how this science agrees with the other sciences in its study of principles. He says that since being is the subject of this kind of science, as has been shown in Book IV (294:C 529-31), and every science must investigate the principles and causes which belong to its subject inasmuch as it is this kind of thing, we must investigate in this science the principles and causes of beings as beings. And this is also what occurs in the other sciences. For there is a cause of health and of its recovery, which the physician seeks. And similarly there are also principles, elements and causes of the objects of mathematics, as figure and number and other things of this kind which the mathematician investigates. And in general every intellectual science, to whatever degree it participates in intellect, must always deal with causes and principles. This is the case whether it deals with purely intelligible things, as divine science does, or with those which are in some way imaginable or sensible in particular but intelligible in general; or even if it deals with sensible things inasmuch as there is science of them, as occurs in the case of mathematics and in that of the philosophy of nature. Or again whether they proceed from universal principles to particular cases in which there is activity, as occurs in the practical sciences, it is always necessary that such sciences deal with principles and causes.

             1146. Now these principles are either more certain to us, as occurs in the natural sciences, because they are closer to sensible things, or they are simpler and prior in nature, as occurs in the mathematical sciences. But cognitions which are only sensory are not the result of principles and causes but of the sensible object itself acting upon the senses. For to proceed from causes to effects or the reverse is not an activity of the senses but only of the intellect. Or "more certain principles" means those which are better known and more deeply probed, and "simple" means those which are studied in a more superficial way, as occurs in the moral sciences, whose principles are derived from those things which occur in the majority of cases.

             1147. But all these (533).

             Second, he shows how the other sciences differ from this science in their study of principles and causes. He says that all these particular sciences which have now been mentioned are about one particular class of being, for example, number, continuous quantity or something of this kind; and each confines its investigations to "its subject genus," i.e., dealing with this class and not with another; for example, the science which deals with number does not deal with continuous quantity. For no one of the other sciences deals "with being in an unqualified sense," i.e., with being in general, or even with any particular being as being; for example, arithmetic does not deal with number as being but as number. For to consider each being as being is proper to metaphysics.

             1148. And since it belongs to the same science to consider both being and the whatness or quiddity, because each thing has being by reason of its quiddity, therefore the other particular sciences make "no mention of," i.e., they do not investigate, the whatness or quiddity of a thing and the definition signifying it. But they proceed "from this," i.e., from the whatness itself of a thing, to other things, using this as an already established principle for the purpose of proving other things.

             1149. Now some sciences make the whatness of their subject evident by means of the senses, as the science which treats of animals understands what an animal is by means of what "is apparent to the senses," i.e., by means of sensation and local motion, by which animal is distinguished from non-animal. And other sciences understand the whatness of their subject by assuming it from some other science, as geometry learns what continuous quantity is from first philosophy. Thus, beginning from the whatness itself of a thing, which has been made known either by the senses or by assuming it from some other science, these sciences demonstrate the proper attributes which belong essentially to the subject-genus with which they deal; for a definition is the middle term in a causal demonstration. But the method of demonstration differs; because some sciences demonstrate with greater necessity, as the mathematical sciences, and others "more weakly," i.e., without necessity, as the sciences of nature, whose demonstrations are based on things that do not pertain to something always but for the most part.

             1150. Another translation has "condition" in place of "assumption," but the meaning is the same; for what is assumed is taken, as it were, by stipulation. And since the starting point of demonstration is definition, it is evident that from this kind of inductive method "there is no demonstration of a thing's substance," i.e., of its essence, or of the definition signifying its whatness; but there is some other method by which definitions are made known, namely, the method of elimination and the other methods which are given in the Posterior Analytics, Book II.

             1151. And just as no particular science settles the issue about the whatness of things, neither does any one of them discuss the existence or nonexistence of the subject-genus with which it deals. This is understandable, because it belongs to the same science to settle the question of a thing's existence and to make known its whatness. For in order to prove that a thing exists its whatness must be taken as the middle term of the demonstration. Now both of these questions belong to the investigation of the philosopher who considers being as being. Therefore every particular science assumes the existence and whatness of its subject, as is stated in Book I of the Posterior Analytics. This is indicated by the fact that no particular science establishes the truth about being in an unqualified sense, or about any being as being.

             1152. And since the philosophy of nature (534).

             Here he shows how this science differs from the other sciences in its method of considering the principles of being as being. And since the philosophy of nature was considered by the ancients to be the first science and the one which would consider being as being, therefore, beginning with it as with what is more evident, he shows, first (534), how the philosophy of nature differs from the practical sciences; and second (535), how it differs from the speculative sciences, showing also the method of study proper to this science ("Now the essence").

             He says, first (534), that the philosophy of nature does not deal with being in an unqualified sense but with some particular class of being, i.e., with natural substance, which has within itself a principle of motion and rest; and from this it is evident that it is neither a practical nor a productive science. For action and production differ, because action is an operation that remains in the agent itself, as choosing, understanding and the like (and for this reason the practical sciences are called moral sciences), whereas production is an operation that passes over into some matter in order to change it, as cutting, burning and the like (and for this reason the productive sciences are called mechanical arts).

             1153. Now it is evident that the philosophy of nature is not a productive science, because the principle of productive sciences is in the maker and not in the thing made, which is the artifact. But the principle of motion in natural bodies is within these natural bodies. Further, the principle of things made by art, which is in the maker, is, first, the intellect which discovers the art; and second, the art which is an intellectual habit; and third, some executive power, such as the motive power by which the artisan executes the work conceived by his art. Hence it is evident that the philosophy of nature is not a productive science.

             1154. And for this reason it is evident that it is not a practical science; for the principle of practical sciences is in the agent, not in the actions or customary operations themselves. This principle is "prohaeresis," i.e., choice; for the object of action and that of choice are the same. Hence it is evident that the philosophy of nature is neither a practical nor a productive science.

             1155. If, then, every science is either practical, productive or theoretical, it follows that the philosophy of nature is a theoretical science. Yet "it is theoretical," or speculative, of a special class of being, namely, that which is subject to motion; for mobile being is the subject matter of the philosophy of nature. And it deals only with "that kind of substance," i.e., the quiddity or essence of a thing, which is for the most part inseparable from matter in its intelligible structure. He adds this because of the intellect, which comes in a sense within the scope of the philosophy of nature, although its substance is separable from matter. Thus it is clear that the philosophy of nature deals with some special subject, which is mobile being, and that it has a special way of defining things, namely, with matter.

             1156. Now the essence (535).

             Here he shows how the philosophy of nature differs from the other speculative sciences in its method of defining things; and in regard to this he does two things. First (535), he explains this difference. Second (538:C 1166), he draws a conclusion about the number of theoretical sciences ("Hence there will be").

             In regard to the first he does three things. First, he exposes the method of defining things which is proper to the philosophy of nature. He says that, in order to understand how the speculative sciences differ from each other, the quiddity of a thing and the way in which "the conceptual expression," i.e., the definition signifying it, should be expressed in each science, must not remain unknown. For in seeking the aforesaid difference "without this," i.e., without knowing how to define things, our search would be unfruitful. For since a definition is the middle term in a demonstration, and is therefore the starting-point of knowing, the difference between the speculative sciences must depend on the different ways of defining things.

             1157. Now concerning things which are defined it must be noted that some are defined like snub and others like concave. And these two differ because the definition of snub includes sensible matter (since snub is merely a curved or concave nose), whereas concavity is defined without sensible matter. For some sensible body, such as fire or water or the like, is not included in the definition of concave or curved. For that is said to be concave whose middle curves away from the ends.

             1158. Now all natural things are defined in a way similar to snub, as is evident both of those parts of an animal which are unlike, for example, nose, eye and face; and of those which are alike, for example, flesh and bone; and also of the whole animal. And the same is true of the parts of plants, for example, leaf, root and bark; and also of the whole plant. For no one of these can be defined without motion; but each includes sensible matter in its definition, and therefore motion, because every kind of sensible matter has its own kind of motion. Thus in the definition of flesh and bone it is necessary that the hot and cold be held to be suitably mixed in some way; and the same is true of other things. From this it is evident what the method is which the philosophy of nature uses in investigating and defining the quiddity of natural things; i.e., it involves sensible matter.

             1159. And for this reason the philosophy of nature also investigates one kind of soul--the kind that is not defined without sensible matter. For in Book II of The Soul he says that a soul is the first actuality of a natural organic body having life potentially. But if any soul can exist separately from a body, then insofar as it is not the actuality of such a body, it does not fall within the scope of the philosophy of nature. Therefore it is evident from the above that the philosophy of nature is a theoretical science, and that it has a special method of defining things.

             1160. But mathematics (536).

             Second, he exposes the method proper to mathematics. He says that mathematics is also a speculative science; for evidently it is neither a practical nor a productive science, since it considers things which are devoid of motion, without which action and production cannot exist. But whether those things which mathematical science considers are immobile and separable from matter in their being is not yet clear. For some men, the Platonists, held that numbers, continuous quantities and other mathematical objects are separate from matter and midway between the Forms and sensible things, as is stated in Book I (70:C 157) and in Book III (183:C 350). But the answer to this question has not yet been fully established by him, but will be established later on.

             1161. However, it is evident that mathematical science studies some things insofar as they are immobile and separate from matter, although they are neither immobile nor separable from matter in being. For their intelligible structure, for example, that of concave or curved, does not contain sensible matter. Hence mathematical science differs from the philosophy of nature in this respect, that while the philosophy of nature considers things whose definitions contain sensible matter (and thus it considers what is not separate insofar as it is not separate), mathematical science considers things whose definitions do not contain sensible matter. And thus even though the things which it considers are not separate from matter, it nevertheless considers them insofar as they are separate.

             1162. Now if there is something (537).

             Third, he exposes the method proper to this science. He says that, if there is something whose being is immobile, and therefore eternal and separable from matter in being, it is evident that the investigation of it belongs to a theoretical science and not to a practical or productive one, whose investigations have to do with certain kinds of motion. However, the study of such being does not belong to the philosophy of nature, for the philosophy of nature deals with certain kinds of beings, namely, mobile ones. Nor likewise does the study of this being belong to mathematics, because mathematics does not consider things which are separable from matter in being but only in their intelligible structure, as has been stated (C 1161). But the study of this being must belong to another science which is prior to both of these, i.e., prior to the philosophy of nature and to mathematics.

             1163. For the philosophy of nature deals with things which are inseparable from matter and mobile, and mathematics deals with certain immobile things, although these are not separate from matter in being but only in their intelligible structure, since in reality they are found in sensible matter. And he says "presumably" because this truth has not yet been established. Further, he says that some mathematical sciences deal with immobile things, as geometry and arithmetic, because some mathematical sciences are applied to motion, as astronomy. But the first science deals with things which are separable from matter in being and are altogether immobile.

             1164. Now common causes must be eternal, because the first causes of beings which are generated must not themselves be generated, otherwise the process of generation would proceed to infinity; and this is true especially of those causes which are altogether immobile and immaterial. For those immaterial and immobile causes are the causes of the sensible things evident to us, because they are beings in the highest degree, and therefore are the cause of other things, as was shown in Book II (151:C 290). From this it is evident that the science which considers beings of this kind is the first of all the sciences and the one which considers the common causes of all beings. Hence there are causes of beings as beings, which are investigated in first philosophy, as he proposed in Book I (14:C 36). And from this it is quite evident that the opinion of those who claimed that Aristotle thought that God is not the cause of the substance of the heavens, but only of their motion, is false.

             1165. However, we must remember that even though things which are separate from matter and motion in being and in their intelligible structure belong to the study of first philosophy, still the philosopher not only investigates these but also sensible things inasmuch as they are beings. Unless perhaps we may say, as Avicenna does, that common things of the kind which this science considers are said to be separate from matter in being, not because they are always without matter, but because they do not necessarily have being in matter, as the objects of mathematics do.

             1166. Hence there will be (538).

             He draws a conclusion as to the number of theoretical sciences. And in regard to this he does three things. First (538), he concludes from what has been laid down above that there are three parts of theoretical philosophy: mathematics, the philosophy of nature, and theology, which is first philosophy.

             1167. For it is obvious (539).

             Second, he gives two reasons why this science is called theology. The first of these is that "it is obvious that if the divine exists anywhere," i.e., if something divine exists in any class of things, it exists in such a nature, namely, in the class of being which is immobile and separate from matter, which this science studies.

             1168. And the most honorable (540).

             He gives the second reason why this science is called theology; and the reason is this: the most honorable science deals with the most honorable class of beings, and this is the one in which divine beings are contained. Therefore, since this science is the most honorable of the sciences because it is the most honorable of the theoretical sciences, as was shown before (32:C 64)--and these are more honorable than the practical sciences, as was stated in Book I (13:C 35)--it is evident that this science deals with divine beings; and therefore it is called theology inasmuch as it is a discourse about divine beings.

             1169. But someone will (541).

             Third, he raises a question about a point already established. First, he states the question, saying that someone can inquire whether first philosophy is universal inasmuch as it considers being in general, or whether it investigates some particular class or a single nature. Now this does not seem to be the case. For this science and the mathematical sciences do not have one and the same method; because geometry and astronomy, which are mathematical sciences, deal with a special nature, whereas first philosophy is universally common to all. Yet the reverse seems to be true, namely, that it deals with a special nature, because it is concerned with things which are separable from matter and immobile, as has been stated (537:C 1163).

             1170. Therefore, if (542).

             Second, he answers this question, saying that if there is no substance other than those which exist in the way that natural substances do, with which the philosophy of nature deals, the philosophy of nature will be the first science. But if there is some immobile substance, this will be prior to natural substance; and therefore the philosophy of nature, which considers this kind of substance, will be first philosophy. And since it is first, it will be universal; and it will be its function to study being as being, both what being is and what the attributes are which belong to being as being. For the science of the primary kind of being and that of being in general are the same, as has been stated at the beginning of Book IV (296:C 533).