Distinctions in Theoretical Philosophy

The following are some notes from a graduate seminar, mostly consisting of ~novel observations rather than recapitulations of the content (as I had on the old version of my site), although I’ll try to include some minimal exposition. This class was on distinctions in theoretical philosophy, run by Nick Jones and Ofra Magidor in Hilary Term 2026.

Worlds (Week 1)

Here’s Lewis’s argument for possible worlds (as rendered on the handout): “Things could have been different in many ways. So: there are many ways things could have been besides the way things are. So: there are many possible worlds other than the one we inhabit.” A concrete possible world is supposed to a real physical universe; an abstract world is supposed to be the (total) way that our universe is (something like a property or state of the universe). Stalnaker notes that Lewis’s considerations might get us to abstract worlds, but not to concrete worlds without some additional work (say, the analogy between worlds and times).

It’s note clear that the ordinary not clear that the considerations about ordinary language and thought mustered by Lewis get you to Atomicity, and not just Actuality + ¬Extensionality. That is, it might get you that there there’s total way that things are (Actuality), and there are other ways that world could be (¬Extensionality); but it’s not clear that the ordinary considerations get us to the conclusion that there are other total ways that things could be. For instance, think of alternate ways that the world could be on the model of (a folk theory of) fictions, where for some reason they cannot even in principle settle everything. Stalnaker himself elsewhere seems to consider denying totality, thinking of worlds as only relative to a (limited in principle) set of questions. Nick thinks this is a good point, although initially thought that it might not have additional bearing on the abstract/concrete world dispute between Stalnaker and Lewis. However, note that it’s much harder for Lewis to appropriate such a way (¬Atomicity) of doing things as legitimising his concrete worlds. How is a spacetime block supposed to be so incomplete in the imagined way? (There are more than two ducks, but no particular number of ducks?) Maybe there’s a (bad) theory of vagueness in the vicinity of this view.

As Ofra notes to the class, the situation for Lewis might be worse than that the ordinary considerations mustered by Lewis get us to abstract but not concrete worlds: for the natural language considerations might also tell against his view about concrete worlds. It’s very odd to think, for instance, that a way (for the world to be) is another concrete universe, rather than something like a property or state of a universe. For instance, consider ‘The actual world is the way that it is’—it’s definitely felicitous, but it seems hard to access an reading with identity ‘is’. But compare ‘James is the man that he is’—it’s similarly hard to access that alternate reading, but this shouldn’t give us the result that James is not quite a man. Ofra thinks this is nice and new, but we didn’t have much time to discuss it during the break.

Meaning (Week 2)

Nothing groundbreaking. Thought some more about taking determiners as type (σt)((σt)t)—note that this applies to both the narrow and wide scope readings. Neat thing that Ofra points out: meaninglessness given presupposition failure might run into trouble with necessitated LEM (what happens to the proposition expressed by `the king of England’ in worlds where there is no king of England?).