BOOK I.
It being our determination to discourse of Natural Philosophy, we judge it necessary, in the first place and chiefly, to divide the body of philosophy into its proper members, so that we may know what is that which is called philosophy, and what part of it is physical, or the explanation of natural things. The Stoics affirm that wisdom is the knowledge of things human and divine; that philosophy is the pursuit of that art which is convenient to this knowledge; that virtue is the sole and sovereign art which is thus convenient; and this distributes itself into three general parts—natural, moral, and logical. By which just reason (they say) philosophy is tripartite; of which one natural, the other moral, the third logical. The natural when our inquiries are concerning the world and all things contained in it; the ethical is the employment of our minds in those things which concern the manners of man's life; the logical (which they also call dialectical) regulates our conversation with others in speaking. Aristotle, Theophrastus, and after them almost all the Peripatetics give the same division of philosophy. It is absolutely requisite that the complete person he contemplator of things which have a being, and the practiser of those thing which are decent; and this easily appears by the following instances. If the question be proposed, whether the sun, which is so conspicuous to us, be informed of a soul or inanimate, he that makes this disquisition is the thinking man; for he proceeds no farther than to consider the nature of that thing which is proposed. Likewise, if the question be propounded, whether the world be infinite, or whether beyond the system of this world there is any real being, all these things are the objects about which the understanding of man is conversant.
But if these be the questions,—what measures must be taken to compose the well-ordered life of man, what are the best methods to govern and educate children, or what are the exact rules whereby sovereigns may command and establish laws,—all these queries are proposed for the sole end of action, and the man skilled therein is the moral and practical man.
CHAPTER I. WHAT IS NATURE?
Since we have undertaken to make a diligent search into Nature, I cannot but conclude it necessary to declare what Nature is. It is very absurd to attempt a discourse of the essence of natural things, and not to understand what is the power and sphere of Nature. If Aristotle be credited, Nature is the principle of motion and rest, in that thing in which it exists as a principle and not by accident. For all things that are conspicuous to our eyes, which are neither fortuitous nor necessary, nor have a divine original, nor acknowledge any such like cause, are called natural and enjoy their proper nature. Of this sort are earth, fire, water, air, plants, animals; to these may be added all things produced from them, such as showers, hail, thunders, hurricanes, and winds. All these confess they had a beginning, none of these were from eternity, but had something as the origin of them; and likewise animals and plants have a principle whence they are produced. But Nature, which in all these things hath the priority, is not only the principle of motion but of repose; whatsoever enjoys the principle of motion, the same has a possibility to find a dissolution. Therefore on this account it is that Nature is the principle of motion and rest.
CHAPTER II. WHAT IS THE DIFFERENCE BETWEEN A PRINCIPLE AND AN ELEMENT?
The followers of Aristotle and Plato conclude that elements are discriminated from principles. Thales the Milesian supposeth that a principle and the elements are one and the same thing, but it is evident that they vastly differ one from another. For the elements are things compounded; but we do pronounce that principles admit not of a composition, nor are the effects of any other being. Those which we call elements are earth, water, air, and fire. But we call those principles which have nothing prior to them out of which they are produced; for otherwise not these themselves, but rather those things whereof they are produced, would be the principles. Now there are some things which have a pre-existence to earth and water, from which they are begotten; to wit, matter, which is without form or shape; then form, which we call [Greek omitted] (actuality); and lastly, privation. Thales therefore is most in error, by affirming that water is both an element and a principle.