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Are we living in a possible world?

May 30, 2008

Assume the following kind of picture. You have possible worlds – maximally specific ways the world can be. Worlds can overlap – one and the same individual may be a part of many different worlds. But suppose also that worlds can overlap in a more extreme way, worlds can share large chunks of history, the same state of affairs, or possible situation might be a part of or exist in many different worlds.

Now ask the question: which world do I belong to? Which of these worlds is mine? Since I exist in many worlds there is no unique answer. But intuitively there should be: ‘the actual world’. My impression, (but that’s all it is) is that people generally think that this is not a particularly deep question – the actual world can just be picked out indexically – ‘the world I belong to’, or ‘this one here’. But as we noted, ‘the world I belong to’ won’t do, I belong to many, and if you follow me in thinking situations are parts of multiple worlds, ‘this one here’ won’t do either. The most I can do is demonstratively pick out the situation I’m currently in – I can specify the situation in so far as I can point to or describe it.

Picking it out indexically is not the way to go. Presumably you will say that the actual world is somehow metaphysically privileged – my world is the metaphysically privileged one. But then there is a puzzle about how non-actual English speakers can say things like ‘We live in the actual world’ – that’s supposed to be true relative to their context of utterence. But if ‘actual’ isn’t working indexically there, it can’t be true. Even if, for some mysterious reason, it is working indexically for them and not for us, we want to know what something with the same linguistic meaning as our utterence would have said in that situation.

What I’m interested in is the idea that we’re not actually in any possible world – that we’re living in some less than maximal possible situation. Maybe there is some metaphysical fact about which situation that is, or maybe the actual situation depends on my context of uttence – I shall leave it open. I just want to see how things pan out.

Here’s one candidate: the actual situation is just everything that’s happened so far. This situation is part of many different possible worlds – it’s part of a possible world in which I get a haircut tomorrow, and a possible world in which I don’t. There is no matter of fact, yet, whether I get a haircut tomorrow, because actuality just doesn’t say anything about it, its incomplete. (Although we could supervaluate and say I either do or I don’t, because in every world which contains actuality, I do or I don’t.) It’s an submaximal situation in so far as the future is genuinely indeterminate.

Here’s another one: maybe the actual situation is incomplete in that it doesn’t make true the following kinds of proposition: the boundaries of mount Everest are thus and so, this droplet is a part of this cloud, and so on. Maybe the world is inherently vague. If we go for the first option, the actual situation depends on context, we simply cannot demonstratively pick out one world where Everest has such and such borders, over the other one where it doesn’t.

Lastly – the actual situation doesn’t include facts like: this quark is located here with these properties. If the actual situation is indeterminate in the way that quantum mechanics says it is, then we might even be able to argue that there is no maximally specific world containing this one. Some situations can’t be extended to a maximally specific world because the physical laws of the situation prohibit it.

Ok, so those are my thoughts so far (a bit brief I know.) It all sounds a bit radical, but I haven’t been able to think up a nice solution to the motivating worry. (It’s not clear that going submaximal in the way I described helps either.) Does anyone know any literature that might be relavent?

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13 comments

  1. Presumably you will say that the actual world is somehow metaphysically privileged – my world is the metaphysically privileged one. But then there is a puzzle about how non-actual English speakers can say things like ‘We live in the actual world’ – that’s supposed to be true relative to their context of utterence.

    How’s this picture: there’s a lump of reality, and various possible states (or stories) which purport to describe it. To say that p is true at w is just to say that p is true according to the story of w. (Or: p would be true if the actual universe were in state w.) There aren’t really any non-actual people, so a fortiori they don’t really make true utterances which correspond to how things really are in their context of utterance. We attribute the semantic value ‘true’ (with an implicit ‘in the fiction’) to literally false claims all the time. Sherlock Holmes speaks “truly” in reporting that he lives on Baker St, etc.

    [Cf. The Actual World is not a Possible World]


  2. Eh, my closing parenthesis turned into an emoticon.


  3. Why should we think “this one here” functions to refer to a temporally limited situation in which I currently find myself? Are you suggesting that there just is nothing at the scale of ‘the world’ which I can refer to? How do you conceive of a world?


  4. What I’m interested in is the idea that we’re not actually in any possible world – that we’re living in some less than maximal possible situation

    I’m not sure how you moved from the epistemological questions, (e.g., which world am I in or can I know which world I’m in) to this (admittedly more interesting) metaphysical worry about whether I exist in any world at all. There is at least one sense in which I’m not in any world, assuming unrestricted composition. There is the ‘I’ that is composed of a stage in world @ and a stage in w. That being exists in no world at all.

    Getting back to the initial worry, it seems perfectly possible (I’d say likely) that I’m not sure what world I’m in. I don’t know, for instance, how the chancy macro-events will unfold. I might think that I’m in a world where those events unfold so that I draw to 21 ten consecutive times while playing blackjack tomorrow. Right now, I think that’s a very distant world. In fact (we might suppose) it is the very world I’m in. No surprise in being wrong there. But how might it lead me to believe I’m exist in (at?) no world?


  5. Hi guys. Thank you all for you comments. Just a few thoughts,

    Richard: this is certainly a coherent picture. However, it seems to be inconsistent with one of my premises (which, for the sake of argument, assume we want to keep) namely that actual situations, i.e. bits of our world, exist in multiple other worlds. Similarly, that actual individuals (concrete things, like you and me) are part of many different worlds – not just represented as such. On this possible states view it seems we have to give up this picture to a certain degree.

    Colin: when I say ‘this one here’, and point, I assume (I think correctly) that this cannot be sufficient to guarantee reference to a maximally specific world. There are infinitely many eligible candidates to be the subject of my utterance. So another way to think about it: what makes one world more eligible than the others? If it’s being metaphysically privileged then we can no longer explain how non-actual beings can demonstratively refer. Would they accidentally refer to our world, making most of their utterances false?

    Mike: the problem I’m interested in is metaphysical (the epistemological worry is kind of beside the point, no-one thinks we are omniscient.) Let Jim be a non-actual person. Then there simply is no such thing as “Jims world” – look at all the worlds that he belongs to, and metaphysically they’re all on a par. There is nothing that makes one of them his world over the others. Now run a similar thought for me. You can now say, all the worlds I belong to aren’t metaphysically on a par, one of them is the actual world. But if *that’s* what makes it my world, there seems to be an intolerable asymmetry between me and Jim. What if, in a non-actual world, I tried to say `it’s actually raining’. Does my utterance end up talking about the actual world, where it isn’t raining? And poor old Jim, whenever he tries to talk about his world, he ends up talking about a world in which he never existed.

    BTW, the point about transworld fusions shouldn’t work in this set up. One of the premises was that two worlds overlap when one object exists in both of them. Me in w and me in @ are identical, so the fusion of them is just me again.


  6. Hmmm…I’m not entirely positive I follow what is going on in this discussion, but it seems to me that if we are interested in a maximally specific world, then we can do it with one added (and not too much of a stretch) “axiom.” Suppose we order the worlds according to “subset inclusion.” Now we have a poset of worlds. Take the chain of sets in which I exist. This should be a totally ordered chain. According to what in mathematics we call Zorn’s Lemma we can choose a maximal element (i.e. the maximally specific world that I am in).

    Comment: The axiom we have to accept is the Axiom of Choice. Not too many people believe that this is true on a “real world” level.


  7. Hi Hilbertthm90,

    AC isn’t quite enough to get us what we want here (at least not straight away.) We need to impose some structure on the set of situations. In this paper I argue that the set of situations under the ordering of being ‘more specific’ form a cpo (that is, a partial order such that each directed set of situations has a supremum.) This can be motivated from considerations of plenitude: if a directed set of situations failed to have a supremum, that would represent an intolerable gap in possibility space.

    Of course, once we know that situations form a complete partial order (in fact, that’s more than we need), we can apply Zorns Lemma and infer the existence of possible worlds, which I also note in the paper.

    Note, though, that Zorns Lemma only says that there *is* a maximal situation. In fact, there will be many extending the one we’re currently in. And that is the problem.


  8. What if, in a non-actual world, I tried to say `it’s actually raining’. Does my utterance end up talking about the actual world, where it isn’t raining?

    I find that confusing. Whether you think there is something that is an ontologically special actual world or not, it will be true in every world w that the utterance in w, ‘I exist in the actual world’ is true in w. We can suppose we are in the actual world–i.e., the special world that differs in ontological status from the rest since it is the only one that is instantiated–but we know that the utterance in possible world w that ‘this world is actual’ is true in w. It is definitely not true in any possible, non-actual w that the definite description ‘the actual world’ refers to our world, despite the special ontological status of our world.


  9. Hi Mike,

    That’s correct – it was supposed to be a reductio of the view that being metaphysically privileged plays a role in determining demonstrative reference.

    What I was asking was, what *does* determine the world of my utterance. If I point to thin air and say ‘that quark is strange’ I think we can safely say I haven’t referred, because there are billions of eligible candidates.

    Similarly, an utterance of ‘this world is actual’ (wherever it is uttered) exists in many different worlds. And since it is part of many different worlds there is no unique world we can call the world of utterance – every world that utterance exists in is eligible to be that utterances world.


  10. Hello – I discovered this post and blog via Richard’s blog, and thought this was a good discussion of an interesting problem. I think that the indexical stance can only extend to the causally connected patch we can observe, and we can’t say anything else beyond that is picked out.

    I think the idea that a world is some distinct whole which extends beyond this patch is problematic. We might do better to identify “actual world” with the patch.

    Best regards,
    – Steve Esser


  11. Andrew,
    The problem of indexicality essentially boils down to this: how do you conceive of possible worlds? If you are a ‘concrete realist’ (ala Lewis) you will hold that actuality is an indexical term; though you will also hold that individuals are worldbound. If you are a ‘erstaz realist’ or a ‘abstractionist’ (ala Adams, Plantinga or Paul), you will hold that possible worlds are maximally complete sets of propositions.
    Your supposition about ‘existing in’ many different possible worlds then commits you to some form of abstractionism or erstatz realism. Properly analyzing this supposition, if you are an actualist or an erstatz realist etc., turns out to just say the following: to say that I exist in more than one possible world at one time is to say that there are many different maximally complete situations of which, if they were to be actualized, I would figure into in some particular way.
    It does not mean that you have a problem of speaking about the world you are in, since the world you are in is the actual world. Your ‘existing in’ many possible worlds does not mean you are somehow sliced about into millions of states of affairs in an infinite amount of possible worlds – but only that there are many different ways in which things might have gone (ways which might have been actual) in which you would have (i) existed therein and (ii) exemplified some particular property.
    I think your conception is perplexing to you because you want to hold concretism while holding to a transworld conception of individuals. Concretism commits one to a worldbound conception, which Lewis happily accepted.
    On a side note, many abstractionists also believe that possible worlds, being merely propositions (or sets of them rather), just ‘match-up’ to our actual world. This being the case, your supposition that your getting a haircut being indeterminate in actuality would be wrong – there is a determinate world which ‘matches-up’ to exactly what happens the next day (in which you either do or do not get a haircut), and that world is the world we call ‘actual’.
    [I think you might find VanInwagen’s “Two Concepts of Possible Worlds” an instructive read]


  12. when I say ‘this one here’, and point, I assume (I think correctly) that this cannot be sufficient to guarantee reference to a maximally specific world. There are infinitely many eligible candidates to be the subject of my utterance.

    Okay now I think I get it. The problem really has more to do with the indeterminacy of reference than it has to do with the indeterminacy of the world. I thought you were suggesting that the world we find ourselves in is, in some way, itself indeterminate (as to which world it is or some such thing).


  13. Well, I think I am suggesting that it’s indeterminate which world we’re in. The way I’m thinking of things here, we are literally in many different worlds. Metaphysically speaking, there is no matter of fact which world we are in.

    It’s probably worth distinguishing that from indeterminacy in the world. On this view that includes possible situations, there are trivially “worlds” that are metaphysically indeterminate. Whether the privileged actual world is one of these indeterminate ones isn’t forced on us – but I think there some reasons to think it isn’t determinate – such as the open future, ontic vagueness, etc…



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