Lecture 5 — The definition of “nature”

Nature means, in one sense, the generation of things that are born, as if one were to pronounce the word “nature” long.

And in another sense it means the immanent principle from which anything generated is first produced.

Again, it means the source of the primary motion in any beings which are by nature, and it is in each inasmuch as it is such. Now all those things are said to be born that grow through something else by touching and by existing together, or by being naturally joined, as in the case of embryos.

But being born together differs from touching, for in the latter case there need be nothing but contact. But in things that are naturally joined together there is some one same thing in both, instead of contact, which causes them to be one, and which makes them to be one in quantity and continuity but not in quality.

Again, nature means the primary thing of which a natural being is composed or from which it comes to be, when it is unformed and immutable by its own power. For example, the bronze of a statue or of bronze articles is said to be their nature, and the wood of wooden things, and the same applies in the case of other things. For each thing comes from these though its primary matter is preserved. For it is also in this sense that men speak of the elements of natural beings as their nature; some calling it fire, others earth, others water, others air, and others something similar to these, whereas others call all of them nature.

In still another sense, nature means the substance of things that are by nature, as those who say that nature is the primary composition of a thing. As Empedocles says, Of nothing that exists is there nature, but only the mixing and separating-out of what has been mixed. Nature is but the name men give to these. For this reason we do not say that things that are or come to be by nature have a nature, even when that from which they can be or come to be is already present, so long as they do not have their form or species. Hence that which is composed of both of these exists by nature, as animals and their parts.

Again, “nature” is the primary matter of a thing, and this in two senses: either what is primary with respect to this particular thing, or primary in general; for example, the primary matter of bronze articles is bronze, but in general it is perhaps water, if everything capable of being liquefied is water.

And nature is also a thing’s form or substance, the terminus of the process of generation. But metaphorically speaking, every substance in general is called “nature” because of form or species, for the nature of a thing is also a kind of substance.

Hence, from what has been said, “nature” in its primary and proper sense is the substance of those things that have within themselves as such the source of their motion. For matter is called nature because it is receptive of this.

And processes of generation and growth are called nature because they are motions proceeding from it. And nature is the source of motion in those things that are by nature, and it is something present in them either potentially or perfectly in act.

Nature

808. Here he gives the different meanings of the term “nature.” And even though an investigation of the term “nature” appears not to belong to first philosophy, but rather to the philosophy of nature, he nevertheless gives the different meanings of this term here, because according to one of its common meanings, nature is predicated of every substance, as he will make clear. Hence it falls under the consideration of first philosophy, just as universal substance does. In regard to this he does two things.

First [808], he distinguishes the different senses in which the term “nature” is used.

Second (1015a13; [824]), he reduces all of these to one primary notion, at hence, from what.

In regard to the first he does two things.

First, he gives five principal senses in which the term “nature” is used.

Second (1015a7; [821]), he gives two additional senses connected with the last two of these, at again, nature.

He accordingly first says that in one sense “nature” means the process of generation of things that are generated, or according to another text which states this in a better way, of things that are born. For not everything that is generated can be said to be born, but only living things (for example, plants and animals and their parts). The generation of non-living things cannot be called “nature,” properly speaking, according to the common use of the term, but only the generation of living things inasmuch as “nature” may mean the nativity or birth of a thing. As if one were to pronounce the word “nature” long. This text is corrupt. This is clear from another translation, which says: as if one were to pronounce the letter “upsilon” long. For physis, which means “nature” in Greek, if it is used to mean the generation of living things, is pronounced with a long upsilon; but if it is used for a principle, as it ordinarily is, it is pronounced with a short upsilon. Yet even from this text it can be understood that the term “nature” means the generation of living things by a certain lengthening or extension of usage.

809. Again, from the fact that “nature” was first used to designate the birth of a thing, there followed a second use of the term, such that “nature” came to mean the principle of generation from which a thing comes to be, or that from which (as from an intrinsic principle) something born is first generated.

810. And as a result of the likeness between birth and other kinds of motion, the meaning of the term “nature” has been extended farther, so that in a third sense it means the source from which motion begins in any being according to its nature, provided that it is present in it insofar as it is such a being and not accidentally. For example, the principle of health, which is the medical art, is not present in a physician who is ill insofar as he is ill, but insofar as he is a physician. And he is not healed insofar as he is a physician, but insofar as he is ill; and thus the source of motion is not in him insofar as he is moved. This is the definition of “nature” given in Physics 2.

811. And because he mentioned things that are born, he also shows what it means in the proper sense to be born, as another text says, and in place of which this text incorrectly says to be generated. For the generation of living things differs from that of non-living things, because a non-living thing is not generated by being joined or united to its generator, as fire is generated by fire and water by water.

But the generation of a living thing comes about through some kind of union with the principle of generation. And because the addition of quantity to quantity causes growth, therefore in the generation of living things there seems to be a certain growth, as when a tree puts forth foliage and fruit. Hence he says that those things are said to be born which grow, that is, have some growth with the principle of generation.

812. But this kind of growth differs from that species of motion which is called “growth,” by which things that are already born are moved or changed. For a thing that grows within itself does so because the part added passes over into the substance of that thing, as food passes over into the substance of the one nourished.

But anything that is born is added to the thing from which it is born as something other and different, and not as something that passes over into its substance. Hence he says that it grows through something distinct or something else, as if to say that this growth comes about through the addition of something that is other or different.

813. But addition that brings about growth can be understood to take place in two ways: in one way, by touching, that is, by contact alone; in another way, by existing together, that is, by the fact that two things are produced together and naturally connected with each other, as the arms and sinews; and by being joined, that is, by the fact that something is naturally adapted to something else already existing, as hair to the head and teeth to the gums.

In place of this another text reads, more appropriately, by being born together with, and by being connected with at birth. Now in the generation of living things, addition comes about not only by contact, but also by a kind of joining together or natural connection, as is evident in the case of embryos, which are not only in contact in the womb, but are also bound to it at the beginning of their generation.

814. Further, he indicates the difference between these two, saying that being fused, that is, being bound together, or being connected at birth, as another text says, differs from contact, because in the case of contact there need be nothing besides the things in contact which makes them one.

But in the case of things that are bound together, whether naturally connected or born together and joined at birth, there must be some one thing instead of contact, that is, in the place of contact, which causes them to be naturally joined, that is, joined or bound together or born together. Moreover, it must be understood that the thing which causes them to be one makes them one in quantity and continuity but not in quality. For a bond does not alter the things bound from their own dispositions.

815. And from this it is evident that anything that is born is always connected with the thing from which it is born. Hence “nature” never means an extrinsic principle, but in every sense in which it is used, it is taken to mean an intrinsic principle.

816. And from this third meaning of “nature” there follows a fourth. For if the source of motion in natural bodies is called their nature, and it seemed to some that the principle of motion in natural bodies is matter, it was for this reason that matter came to be called nature, which is taken as a principle of a thing, both as to its being and as to its becoming. And it is also considered to be without any form, and is not moved by itself, but by something else. He accordingly says that nature is spoken of as that primary thing of which any being is composed or from which it comes to be.

817. He says this because matter is a principle both of being and of becoming. Hence he says that it is without order, that is, form, and for this reason another text says when it is unformed. In the case of some things, their order (or arrangement) is regarded as their form, as in the case of an army or of a city. From this, he says that it is immutable by its own power: it cannot be moved by its own power, but by that of a higher agent. For matter does not move itself to acquire a form but is moved by a higher and extrinsic agent. For instance, we might say that bronze is the nature of a statue or of bronze vessels or wood of wooden, as if such vessels were natural bodies. The same is true of everything else that is composed of or comes to be from matter, for each comes to be from its matter, though this is preserved. But in the process of generation, the dispositions of a form are not preserved; for when one form is introduced, another is cast out. And for this reason it seemed to some thinkers that forms are accidents and that matter alone is substance and nature, as he points out in the Physics 2.

818. They held this view because they considered the matter and form of natural bodies in the same way as they did the matter and form of things made by art, in which forms are merely accidents and matter alone is substance.

It was in this sense that the philosophers of nature said that the elements are the matter of things that come to be by nature, that is, water, air, fire, or earth, which no philosopher has held to be the element of natural beings all by itself, although some of those who were not philosophers of nature did hold this, as was stated in book 1 [134].

And some philosophers, such as Parmenides, held that some of these are the elements and natures of things; others, such as Empedocles, held that all four are the elements of things; but others held that something different is the element of things, such as Heraclitus held of vapor.

819. Now, because motion is caused in natural bodies by the form rather than by the matter, he therefore adds a fifth sense in which the term “nature” is used: that in which it means the form of a thing. Hence in another sense “nature” means the substance of things, that is, the form of things, which are by nature. It was in this sense that some said that the nature of things is the composition of mixed bodies, as Empedocles said that there is nothing absolute in the world, but that only the alteration or loosening (or mixing, according to another text) of what has been mixed is called “nature” by men. For they said that things composed of different mixtures have different natures.

820. Now they were led to hold that form is nature by this process of reasoning. Whatever things exist or come to be by nature are not said to have a nature, even though the matter from which they are naturally disposed to be or to come to be is already present, unless they have a proper species and a form through which they acquire their species. Now the term “species” seems to be given in place of substantial form and the term “form” in place of figure, which is a natural result of the species and a sign of it. Hence, if form is nature, a thing cannot be said to have a nature unless it has a form. Therefore, that which is composed of matter and form is said to be by nature, according to nature, as animals and the parts of animals, such as flesh and bones and the like.

821. Again, nature (1015a7). Then he gives two meanings of nature which are connected with the last two preceding ones, and the first of these is added to the fourth sense of nature, in which it means the matter of a thing. And he says that not every kind of matter is said to be the nature of a thing but only first matter.

This can be understood in two senses: either with reference to something generic, or with reference to something that is first absolutely or without qualification. For example, the first matter generically of artificial things produced from bronze is bronze, but their first matter without qualification is water, for all things that are liquefied by heat and solidified by cold have the character of water, as he says in Meteorology 4.

822. He links up the second of these additional meanings with the fifth sense of “nature” mentioned above, according to which “nature” means form. And in this sense, not only is the form of a part called “nature,” but the species is the form of the whole. For example, we might say that the nature of man is not only a soul but humanity and the substance signified by the definition.

For it is from this point of view that Boethius says that the nature of a thing is the specific difference which informs each thing, because the specific difference is the principle that completes a thing’s substance and gives it its species.

And just as form or matter is called nature because it is a principle of generation, which is the meaning of nature according to the original use of the term, in a similar way the species or substance of a thing is called its nature because it is the end of the process of generation. For the process of generation terminates in the species of the thing generated, which is a result of the union of matter and form.

823. And because of this, every substance is called “nature” according to a kind of metaphorical and extended use of the term, for the nature which we spoke of as the terminus of generation is a substance. Thus every substance is similar to what we call nature. Boethius also gives this meaning of the term. Moreover, it is because of this meaning that the term “nature” is distinguished from other common terms. For it is common in this way just as substance also is.

824. Hence, from what (1015a13). Then he reduces all of the foregoing senses of the term “nature” to one common notion. But it must be noted that the reduction of the other senses to one primary sense can happen in two ways: in one way, with reference to the order which things have; and in another way, with reference to the order which is observed in giving names to things.

For names are given to things according as we understand them, because names are signs of what we understand; and sometimes we understand prior things from subsequent ones. Hence something that is prior for us receives a name which subsequently fits the object of that name. And this is what happens in the present case, for, since the forms and powers of things are known from their activities, the process of generation or birth of a thing is the first to receive the name of “nature,” and the last is the form.

825. But with reference to the order which things have in reality, the concept of “nature” primarily fits the form, because, as has been said [808], nothing is said to have a nature unless it has a form.

826. Hence from what has been said it is evident that in its primary and proper sense “nature” is the substance, that is, the form, of those things that have within themselves as such the source of their motion. For matter is called “nature” because it is receptive of form, and processes of generation get the name of “nature” because they are motions proceeding from a form and terminating in further forms. And this form is the principle of motion in those things that are by nature, either potentially or actually. For a form is not always the cause of actual motion, but sometimes only of potential motion, as when a natural motion is prevented by an external obstacle, or even when a natural action is prevented by a defect in the matter.