Tuesday, November 25, 2008

Indeterminate truthmaking

Recently, I’ve been thinking a lot about how to think about truthmaker theory if there’s ontic indeterminacy. If you thought that p’s being indeterminate amounted to p’s lacking a truth-value and you were a truthmaker maximalist, your life would be quite easy: you could say that ‘p is indeterminate’ is true just because there’s neither a truthmaker for p not a truthmaker for not-p.

But I, following Elizabeth and Robbie’s work, have committed to the view of ontic indeterminacy whereby ‘p is indeterminate’ does not entail a truth-value gap. ‘Indeterminately, p’, on this bivalent view, is compatible with both the truth of p and the falsity of p. p is either true or false, it’s just unsettled which.

On this view, there’s a gap between truth and determinate truth, and it’s an interesting question in that case what the truthmaker theorist should say. One option is that ‘Indeterminately, p’ and ‘Determinately, p’ just get treated like any other proposition, and get assigned possible truthmakers, but I prefer the option that says we should assign possible truthmakers only to the ‘indeterminacy free’ propositions, and determine the truth-value of the ‘determinacy involving’ propositions based on whether those truthmakers determinately exist or exist but not determinately so.

So the idea is that, e.g., the state of affairs of Ball being red makes it true that Ball is red. And if it’s determinately true that Ball is red that’s not because there’s some further thing, the state of affairs of Ball being determinately red, but rather because the state of affairs of Ball being red is a determinate existent. The thought being that if p is determinately true at one world and true but not determinate at another, it is difference in being enough if the truthmaker for p is a determinate existent at the former world and a mere existent (one which exists, but not determinately so) at the latter. (You can think of this as a difference in the way that the truthmaker exists, or alternatively allow yourself extra ideology – see section 7 of this paper.)

Now, if every proposition got mapped onto exactly one possible truthmaker, life would be simple. But it doesn’t, and it’s not. p might be determinately true not because there is some truthmaker for p that determinately exists but rather because it’s determinate that there exists some truthmaker for p. The case I’m most interested in is the open future. If there’s a fixed past but open future then, I say (see my joint paper with Elizabeth), there’re a bunch of candidate states of the world being a certain way throughout history that agree on how things were and are but disagree on how things will be, and it’s determinate that exactly one of these states exists, but indeterminate which.

It’s determinate that young Earth creationism is wrong because there’s determinately a truthmaker for ‘Dinosaurs existed millions of years ago’ – but there’s no determinately existing truthmaker for that proposition. Each candidate state would make that true, and it’s determinate that one exists, so it’s determinate that it’s made true. ‘Martian colonies will exist in a hundred years’, on the other hand, is neither determinately true nor false, since if a certain candidate state exists it will be made true and if another exists it will be made false, and it’s not determinate which exists.

Exactly one of these candidate states gets things right – it gives us the actual history of the world – so that state exists and all the others don’t. But none of them get it determinately right or wrong, so the existent state is a mere existent and the non-existent states mere non-existents. But saying this doesn’t tell us that it’s determinate that exactly one of these states exists, so we need to either take that as a brute fact or admit a disjunctive state of affairs – the state of affairs of this world state existing or that world state existing or . . . etc – and proclaim it to be a determinate existent.

A decision has to be made when it comes to non-existence. Truthmaker theorists disagree as to whether to admit truthmakers for negative existentials or to let explanation bottom out at facts about what there is not as well as facts about what there is. But either way, the story is going to be more complicated once it can be indeterminate what there is.

Suppose a determinately exists, b exists but not determinately so, c fails to exist but not determinately so, and every other possible existent determinately fails to exist. If you are not a truthmaker maximalist and want to take facts about what there is not as brute you still have to be able to distinguish between the mere non-existence of c and the determinate non-existence of d (say). If you were inclined to believe in two ways of being – determinate and mere being – you should now postulate two ways of non-being – determinate and mere non-being. On this view, to completely determine a world, what God has to do is to say of every possible being which of the four ways of being or non-being it has: once He’s done that, He’ll have settled everything there is to settle. (At least provided that the disjunctive states of affairs mentioned above number amongst the possibilia.)

Now suppose we are attracted to maximalism. Since a and b are the only things there are, we must admit the existence of the second-order totality state of affairs of a and b being the only first-order things that there are. Now for Armstrong, you can stop there: there’s no need to posit an additional third-order totality state of affairs saying of the second-order totality state of affairs that it’s the only second-order totality state of affairs that there is; that’s because it’s necessarily true that there’s only one second-order totality state of affairs, and hence it can itself make it true that it’s the only one. And so there’s no risk of regress. But if it’s not determinate what there is, it will likewise not be determinate what second-order totality state of affairs exists. In our situation it’s not determinate that a and b are all the things there are: both the totality state of affairs of a being the only thing, and of a, b and c being the only things, are non-existents, but they are mere non-existents. However, since it’s determinate that exactly one of these totality facts exists we can’t stop at the postulation of the second-order totality state of affairs; we need to admit a new entity: the disjunctive state of affairs of one of these three totality states of affairs existing. And now we need another new entity – a third-order totality state of affairs – that says that everything we’ve talked about so far are all the things that exist at levels one and two. In essence, this third-order totality state of affairs is the thing that makes it true that all the candidate second-order totality states of affairs are all the candidate second-order totality states of affairs.

Now, our story can stop here if it’s necessarily true that whatever third-order totality state of affairs exists, it is determinately the only third-order totality state of affairs that exists. But if it’s possible for there to be higher-order indeterminacy in what there is – that is, if it’s possible that it’s indeterminate not just what the totality of entities is but what the candidate totalities are – then the third-order totality state of affairs itself may be a mere existent. There could be other candidate third-order totality states of affairs, and it not be determinate which of them exists. But it will be determinate that one of them does . . . and so we’re off on a regress. Now personally, I doubt the coherence of higher-order indeterminacy; I think that while it might be indeterminate what there is, it necessarily won’t be indeterminate what the range of candidate totalities are, and so I think the maximalist will be able to stop at the determinately existing third-order totality state of affairs and resist infinite regress.

Anyway, I go into all of this in more detail in sections 6 and 7 (and 8 to a lesser degree) of my Truthmaking for Presentists paper. If anyone has any comments on either what’s written here or there, I’d welcome them.

Academics as border police

New rules on overseas students are being introduced by the Government, which will involve academics having to report to the Border Agency when such students have missed a certain number of contact hours. If you are a British citizen or resident and think it is not our role to act as immigration officers, that such rules threaten the autonomy of Universities, that they will make it harder for us to attract overseas students, or that this is generally a Bad Idea, please sign the petition below:


Monday, November 24, 2008

Job: deadline this Friday

Just a last reminder that the deadline for applications for the lecturer or senior lecturer at Leeds (in US terms, roughly equivalent to a tenured assistant or associate prof respectively) is THIS FRIDAY (28th).

For details on how to apply, see the post below.

Wednesday, November 12, 2008

Leeds job: reminder

Just a reminder that the deadline for the lecturer/senior lecturer position at Leeds is Nov 28th: just over two weeks from the time of posting.

AOS is open over all areas of the department, but we're particularly interested in applicants working in Theoretical Philosophy (broadly construed: so logic, phil logic, phil language, epistemology, metaphysics, phil of maths, phil mind etc) or the history of philosophy.

For the job ad go here (and scroll down a bit).