Compendium of All Natural Science

ries, there is a need not only for two, but for more. For when heat is to be introduced, if the transmutation began from coldness, two things will seem to have been contraries. For both the privation of heat and coldness itself are opposed to that one heat. But it happened by chance that the heat began to be transmuted from coldness; for it could have happened that it had begun from lukewarmness.

5. On matter.

Matter indeed and form are principles, and the first foundations in composition, but the last in resolution; for which reason both are called natures. For they are those things through which natural things are separated from those that are not natural. Matter, however, is twofold: one indeed which, since it is potentially the recipient of all forms, can neither be corrupted nor generated; the other which, since it is subjected to the substantial form of natural things, is formed from that first matter and from qualities, whence as soon as the principal form is received, a certain composite thing is generated. The composite, moreover, is the principle of all transmutations, as can easily be evident to those who consider it. Matter, however, is the principle not of all transmutations, but only of those which end in a substantial form or a quality. For those transmutations which occur by understanding depend upon no matter, since they neither add any form, or