Potentiality is not the same as possibility. Potentiality is a kind of power or capacity; possibility is a way things could be. Someone might have the potential to become a concert pianist but this might not actually be a possibility because of circumstances (no pianos to practice on, no teachers, etc.). And someone might possibly be a concert pianist but not have the potential to be one because of a lack of innate talent combined with suitable brain surgery. So nothing in the theory of possibility gives us automatic insight into potentiality (it isn’t simply a matter of what holds in various possible worlds). Nor is potentiality the same as the having of dispositions: to be potentially X is not to be disposed to be X (someone might be disposed to become an alcoholic rather than the concert pianist they have to potential to become). The potential is not the possible or dispositional but a sui generis type of fact. And it is a puzzling type of fact: somehow the future is “contained in” the present (or past)—implicit, foretold, prefigured. It is both there and not there—present only potentially. The acorn is potentially an oak tree (not a birch or a deer)—that is what it has the capacity to be. It is as if the acorn dreams of being an oak tree but not of other destinies. The case is like meaning and use: the use is “contained in” the meaning, but it is not as if the meaning consists of all the uses—it isn’t that the meaning is a compacted sequence of implicit uses (whatever that may mean).  Brave acts are prefigured in the brave man and not the coward, but he may have done nothing brave in his entire life if the occasion has not arisen. The potentiality is a ghostly presence, bathed in philosophical obscurity. Yet the world is full of potentiality, especially the biological world: it is populated with these shadowy enigmatic facts. They are “queer”, inhospitable to empiricism, and not reducible to anything else. Maybe everything harbors a potentiality of some sort. Maybe properties are essentially potentialities. 
 Wittgenstein had a strong interest in the concept of the potential: his discussion of meaning in the Investigations is steeped in the idea (see in particular his remarks on machines in sections 193 and 194).
 This kind of potentiality metaphysics implies that the present is always “bound up” with the future, so that every present fact “makes reference” to future facts (apologies for the scare quotes). Reality thus becomes temporally distributed in some hard-to-grasp way.