“[T]he rational powers are powers for two contrary effects: but two contraries cannot be actualized at the same moment by the same power. What is thus necessary (ananke) — but this time by a logical necessity, dictated by the principle of non-contradiction — is that there intervenes, in addition to dunamis, another principle: desire or deliberated choice, orexis or prohairesis, which chooses between the two contraries.”
“We can thus reformulate the definition so that it serves for the dunaton kata logon: it is necessary (ananke) when that which is capable according to reason [what was called a rational power] desires something for which it has the power, that it does that thing. The necessary sequence begins this time from the power insofar as it is modified by desire and/or by choice — and thus by liberty. It remains that, here again, the attribution of such a power implies the taking into account of the circumstances of its effectuation. According to this new determination, that is possible which is decided or desired by the agent, and which the circumstances allow (which its deliberation must take into account)” (Aubry, Dieu san la puissance, 2nd ed., ch. 4, pp. 127-128, my translation throughout).
Aristotle doesn’t literally offer a new definition of possibility at this point, but the effect is similar. In Sachs’ translation, he says that one having a rational power too “has the potency in the sense that it is a potency for acting, and this is not in every situation but when things are in certain conditions…. [E]ven if one wishes and desires… to do contrary things, one will not do them, for… there is no potency for doing them at the same time, since a thing will do the things it is capable of in the way that it is capable of them” (Metaphysics, book Theta ch. 5, p. 173).
All power or potency for Aristotle is the power to do something definite, and every power to do something definite is capable of doing it only under certain conditions. Consequently, there could be no such thing as an indefinite or unlimited power.
The emphasis on contraries in the case of rational powers is a little confusing, but it seems to be a further consequence of the notion that all power is definite. He seems to consider deliberation about the use of definite powers as revolving around the question whether to use them or not, which does thus acquire a kind of binary flavor. But it seems to me that a being having multiple powers might also deliberate about which of several to apply in a given situation.
What is really essential here is that rational power belongs to beings that deliberate. This is what makes it “rational”. And Aristotle sees a kind of “rational” (rather than physical) necessity that a being that desires or chooses something and has the power for it, will do it. But because it incorporates deliberation and choice among its conditions, this kind of necessity is not that of determinism. It is a hypothetical necessity that is compatible with contingency.
Returning to Aubry’s argument, “Proairesis [choice based on deliberation] thus intervenes as a principle of contingency, capable of inaugurating a necessary causal sequence. If the circumstantial definition of the possible leaves no place for logical possibility but tends to identify possible and potential, on the other hand the distinction between potential and actual is maintained.”
“But to this it is necessary to add — and this is what Theta 8 will do — that power considered in itself, and not in relation to its effect, is a principle of contingency. Every power, taken not as principle of action but in opposition to act, considered thus in its ontological determination and not only a kinetic one, is the place of an essential indetermination” (p. 129).
So by a sort of dialectical twist, Aubry momentarily attributes a kind of determinism to Aristotle, and then refutes it two pages later. On pedagogical grounds, I don’t favor the deliberate construction of unnecessary dialectical surprises, just as I don’t stylistically favor the kind of construction that first seemingly makes an unqualified statement, then adds qualifications later on. If a statement will later be qualified, it is good to give some indication of that up front. But in context this a minor point, and partly a personal preference of mine that Aristotle doesn’t follow either. The thing to emphasize here is that Aristotle simultaneously argues for an essential contingency in all power that is incompatible with determinism, and at the same time for the role of a hypothetical, delimited necessity that is compatible with contingency.
“It is on this essential contingency of power that the antideterminist argument of On Interpretation rests. Aristotle there distinguishes not only, like in Theta 4, the impossible from the false, but the possible from the true: of certain possible propositions, one cannot say in advance whether they will be true or false…. The possible is thus distinguished at once from the actual, the necessary, and the true” (ibid).
She summarizes Aristotle’s famous discussion in On Interpretation of the sea battle that may or may not happen tomorrow. At the most obvious level, this has to do with human deliberation and choice.
“But again Aristotle gives this another extension: if the future depends on decision and on human action, it is also true, and this time in a general (holos) manner, that ‘in all that which does not act always, there is a possibility of being and of not being. This indetermination in virtue of which the future must be called contingent, and the propositions concerning it neither true nor false, also affects events involving irrational powers” (p. 130).
Here we come full circle, to Aristotle’s rejection of strict determinism in the action of natural powers as well rational ones.
Next in this series: The Relativity of Dynamis
The Postmodern Peripatetic 