Plutarch De Fato 6

[6] These things being so, we are next in order to show, how that which is in our power (or free will), Fortune, possible, contingent, and other like things which are placed among the antecedent causes, can consist with Fate, and Fate with them; for Fate, as it seems, comprehends all things, and yet all these things will not happen by necessity, but every one of them according to the principle of its nature. Now the nature of the possible is to presubsist, as the genus, and to go before the contingent; and the contingent, as the matter and subject, is to be presupposed to free will; and our free will ought as a master to make use of the contingent; and Fortune comes in by the side of free will, through the property of the contingent of inclining to either part. Now you will more easily apprehend what has been said, if you shall consider that every thing which is generated, and the generation itself, is not done without a generative faculty or power, and the power is not without a substance. As for example, neither the generation of man, nor that which is generated, is without a power; but this power is about man, and man himself is the substance. Now the power or faculty is between the substance, which is the powerful, and the generation and the thing generated, which are both possibles. There being then these three things, the power, the powerful, and the possible; before the power can exist, the powerful must of necessity be presupposed as its subject, and the power must also necessarily subsist before the possible. By this deduction then may in some measure be understood what is meant by possible; which may be grossly defined as that which power is able to produce; or yet more exactly, if to this same there be added, provided there be nothing from without to hinder or obstruct it. Now of possible things there are some which can never be hindered, as are those in heaven, to wit, the rising and setting of the stars, and the like to these; but others may indeed be hindered, as are the most part of human things, and many also of those which are done in the air. The first, as being done by necessity, are called necessary; the others, which may fall one way or other, are called contingent; and they may both thus be described. The necessary possible is that whose contrary is impossible; and the contingent possible is that whose contrary is also possible. For that the sun should set is a thing both necessary and possible, forasmuch as it is contrary to this that the sun should not set, which is impossible; but that, when the sun is set, there should be rain or not rain, both the one and the other is possible and contingent. And the again of things contingent, some happen oftener, others rarely and not so often, others fall out equally or indifferently, as well the one way as the other, even as it happens. Now it is manifest that those are contrary to one another, — to wit, those which fall out oftener and those which happen but seldom, — and they both for the most part depend on Nature; but that which happens equally, as much one way as another, depends on ourselves. For that under the Dog it should be either hot or cold, the one oftener, the other seldomer, are both things subject to Nature; but to walk and not to walk, and all such things of which both the one and the other are submitted to the free will of man, are said to be in us and our election; but rather more generally to be in us. For there are two sorts of this being in our power; the one of which proceeds from some sudden passion and motion of the mind, as from anger or pleasure; the other from the discourse and judgment of reason, which may properly be said to be in our election. And some reason there is to believe that this possible and contingent is the same thing with that which is said to be in us and according to our free will, although differently named. For in respect to the future, it is styled possible and contingent; and in respect of the present, it is named in our power and in our free will. So that these things may thus be defined: The contingent is that which is itself — as well as its contrary — possible; and that which is in our power is one part of the contingent, to wit, that which now takes place according to our will. Thus have we in a manner declared, that the possible in the order of Nature precedes the contingent, and that the contingent subsists before free will; as also what each of them is, whence they are so named, and what are the qualities adjoined or appertaining to them.