A. About the Meaning of the Term ‘Natural’

231. Here one needs to understand that ‘natural’ is taken equivocally [cf. Ord. prol. nn.57-59] - which is plain from the fact it has diverse opposites.

232. And this is one teaching about knowing what is multiple, for in Topics 1.15.106a9-10 the natural in one way is opposed to the supernatural, in another way to the artificial (or to the free or voluntary), in a third way to the violent.

233. For naturality sometimes pertains to the active principle, and then are opposed to it the free in one way and the supernatural in another way - for a natural agent or an agent acting naturally (which is opposed to the free) is said to be that which acts of natural necessity, while the voluntary or the free is that which determines itself to acting. And in this way does the Philosopher speak in Physics 2.3.195a27-b6, 5.196b17-22, when he divides nature from what acts by design, and in Metaphysics 9.2.1046a22-b2, 5.1047b31-8a8, when he speaks about irrational active powers and rational or free active powers. In another way the natural, on the part of the active principle, is said to be what has a natural order of active to passive, and the supernatural what exceeds all such natural order; and in this way any created agent is said to be natural and only an uncreated agent is said to be supernatural.

234. On the part of the passive principle, the natural is spoken of in one way as it is opposed to the violent, insofar as it is said to be moved naturally because it is acted on according to its proper inclination as passive; the violent is what is acted on against its inclination as passive. From this follows that the natural and violent are not immediate contrary opposites; rather there is a mean between them, namely when the passive thing is disposed in neither way, and is not inclined to what it receives nor to what is opposite (as a surface is disposed to whiteness or to blackness or to something intermediate).

235. There follows too that the violent cannot exist in what is primarily passive, namely in prime matter, because prime matter is never inclined against anything that it is absolutely receptive of.

236. And the distinction between these opposites and the intermediate in the passive thing is taken as it is compared to form. But as the passive thing is compared to the agent from which it receives the form, it is said to be moved naturally when it is moved by an agent naturally corresponding to it; however, it is said to be moved supernaturally when it is moved by an agent proportioned to it naturally above the whole order of these sorts of agents.

237. Thus we have, therefore, in two ways the natural as it belongs to the active principle, because we have it as it is distinguished from the free and supernatural [n.233]; and we have in two ways the natural or naturally as it belongs to the passive thing, because we have it as it is distinguished from the neutrals and the violent [n.234].