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.