Section 4

Nature 1 means: (a) in one sense, the genesis of growing things—as would be suggested by pronouncing the υ of φύσις long—and (b) in another, that immanent thing 2 from which a growing thing first begins to grow. (c) The source from which the primary motion in every natural object is induced in that object as such. All things are said to grow which gain increase through something else by contact and organic unity (or adhesion, as in the case of embryos).

Organic unity differs from contact; for in the latter case there need be nothing except contact, but in both the things which form an organic unity there is some one and the same thing which produces, instead of mere contact, a unity which is organic, continuous and quantitative (but not qualitative).

Again, nature means (d) the primary stuff, shapeless and unchangeable from its own potency, of which any natural object consists or from which it is produced; e.g., bronze is called the nature of a statue and of bronze articles, and wood that of wooden ones, and similarly in all other cases.

For each article consists of these natures, the primary material persisting. It is in this sense that men call the elements of natural objects the nature, some calling it fire, others earth or air or water, others something else similar, others some of these, and others all of them.

Again in another sense nature means (e) the substance of natural objects; as in the case of those who say that the nature is the primary composition of a thing, or as Empedocles says: Of nothing that exists is there nature, but only mixture and separation of what has been mixed; nature is but a name given to these by men. 3

Hence as regards those things which exist or are produced by nature, although that from which they naturally are produced or exist is already present, we say that they have not their nature yet unless they have their form and shape.

That which comprises both of these exists by nature; e.g. animals and their parts. And nature is both the primary matter (and this in two senses: either primary in relation to the thing, or primary in general; e.g., in bronze articles the primary matter in relation to those articles is bronze, but in general it is perhaps water—that is if all things which can be melted are water) and the form or essence, i.e. the end of the process, of generation. Indeed from this sense of nature, by an extension of meaning, every essence in general is called nature, because the nature of anything is a kind of essence.

From what has been said, then, the primary and proper sense of nature is the essence of those things which contain in themselves as such a source of motion; for the matter is called nature because it is capable of receiving the nature, and the processes of generation and growth are called nature because they are motions derived from it. And nature in this sense is the source of motion in natural objects, which is somehow inherent in them, either potentially or actually.