I think modern philosophy generally is handicapped in its thinking about the empirical world by its lack of a notion like Aristotelian potentiality. To build context, I need to first say a bit more about the role of actuality.
The modern concept of a factual, existing world is relatively close to Aristotelian actuality, but the first big difference is that it is not paired with anything. The modern concept of a factual world is something that is supposed to be complete in itself, whereas for Aristotle, actuality in the world is always complemented by some correlative potentiality. Aristotle did not consider actuality alone to be sufficient to account for the world as we experience it.
Actuality also does not exactly correspond to a state of things, but rather expresses what is effectively operative. This is semantically a bit deeper than a notion of state. At the same time, it does not have state’s strong implications of complete determination. It also does not have the monolithic unity of a state. Actuality in the world consists of many coexisting things. Further, it is not intended by itself to provide all the resources needed to account for change and what happens next. This is related to the fact that for Aristotle, the operative determination of things is not entirely univocal. (See also Equivocal Determination.)
Enter potentiality. Potentiality is exactly what is not univocal in the actual determination of things. It corresponds to multiple alternative concrete possibilities of realization already implicit in current reality. This is a far more specific notion than mere logical possibility. Potentiality is closely tied to and informed by the current actuality, in that it exactly occupies the real gaps or holes in the actuality’s incompletely univocal determination. For each aspect of things where there is not univocal determination, there are instead multiple potential alternatives. This correlates with the fact that, for Aristotle — in contrast to Poincaré’s classic formulation of modern determinism — the present does not completely determine the future.
Poincaré famously claimed that from the state of the universe at any arbitrary point in time, its entire future is completely determined. This resembles the Stoic notion of fate, transferred to a modern event-based model of causality. For both the Stoics and Poincaré, the world is completely univocally determined. Like Aristotle, they emphasized the intelligibility of the world and of change in the world, but they made the very strong assumption of complete univocal determination. Aristotle did not.
Aristotle’s notion of intelligibility was broadly semantic, whereas Poincaré’s was mathematical. With semantic interpretation, there is always a question of how far we develop the account, which in principle could be extended indefinitely. It thus naturally lends itself to an account of incomplete determination, corresponding to some stopping point. Aristotle does not claim any more determination than he can show. Poincaré’s approach, by contrast, requires that we assume there is a complete univocal determination of the world by mathematical laws, even though we can never even come close to knowing enough to show it. This assumption leaves no room for anything like potentiality. Potentiality, it seems to me, could only have a place in a semantic approach to intelligibility.
The modern factual world is usually considered as something that just is, without modal qualification, but I have increasingly begun to doubt whether for Aristotle there is any non-modal account of the world. I read actuality and potentiality both as modal concepts, and everything in the Aristotelian world as parsable into actuality and potentiality.
What’s important about this is that potentiality is not just some mysterious “metaphysical” concept that we could maybe do without. It is a distinct logical/semantic modality supporting multiple virtual alternatives for the same thing. It allows us to intelligibly account for the incomplete determination we really experience, rather than treating real-world incompleteness and ambiguity as if it were a kind of flaw. (See also Structural Causality, Choice; Values, Causality; Structure, Potentiality.)
The Postmodern Peripatetic 