transcript Saunders discussion

July 20 11.30
Explaining probability
Speaker: Simon Saunders
Commentator: Oliver Pooley
Floor speakers (in order of appearance)
Butterfield
Greaves
Loewer
Wallace
Papineau
Rae
Williamson
Bacciagaluppi
Lewis
Sudbery
Hawthorne
Albert
Tappenden




101

Comment by Pooley

1. The main thing I was going to discuss is the particular proposal, the particular claim about overlap and how to understand these indexical utterances in the context of a branching world but I want to do two other things as well, I want to start by setting out the landscape and just trying to situate what Simon’s doing with respect to some of the problems for the Everett interpretation that have been raised over the last couple of days. And the second thing is I want to defend Lewis a bit in this context. So, just setting out the landscape, what I’ve picked up is that in defending Everett there are two things to do and one naturally comes before the other. The first is to show how from the fundamental ontology we can identify or locate or get out of it something that is, at least subjectively, our familiar everyday world and I take it that the criticisms of Tim and some of the things John Hawthorne was saying were criticisms along those lines pointing out difficulties for that project and what David [Wallace] was saying at the start was a defence and a sketch of how that should go. The second lot of problems only arise once that’s on the table, so you take it for granted that we have this branching structure which represents a branching universe of the kind we’re familiar with in our everyday perception and so on and then the problem is meant to be, well, the way to understand our situation in such a universe is as radically mistaken and, in particular, the very theory in such a situation is empirically self-undermining. So I take it that was the tenor of David Albert’s problems raised yesterday. And Hilary, Wayne and David, I take it, in a sense agree that the inhabitants of this universe, until they discovered Everett, were radically mistaken, then Hilary and Wayne say: but that doesn’t matter, you can still understand how the inhabitants of such a universe can confirm their theory of the universe in that branching situation. David says they can’t.

2. Simon, I take it, wants to say something different. David and Simon want to say, no, the right way to think about it is that the inhabitants of such a universe weren’t radically mistaken. Now what I haven’t got is how that part of what they want to say connects to the confirmation and explanatory issues that were at the heart of David Albert’s criticisms, so I can understand you saying, look, there really is uncertainty here, it’s important for justifying our talk of probability and really making that talk okay, that I can find uncertainty in here, but what I haven’t understood is whether that’s part of a reply to the confirmatory or explanatory criticisms.

3. So let me move on to the particular proposal. Rather than talk about the modal case I want to start by talking at least about the Parfittian case. And I think it’s worth giving a bit of background to the situation in which David Lewis ended up saying this. The situation was that Parfit suggest that what goes on in a kind of block universe (well, I’m not sure whether Parfit is a block universe theorist or not but let’s pretend that’s the way he’s thinking), the right thing to say in the block universe picture is that you’ve just got these various experiential happenings in space and time and then, say, this one is a thought at t-zero,[referring to board] “Will I survive to t-one”. Am?..I around at t-one? And for Parfit it’s true that the thinker of this thought is around at t-one just in case there is an experiencing subject at t-one who’s related to the experiencing subject at t-zero in the right kind of causal and psychological ways. So the identity of the subject at t-zero and the subject at t-one just is a matter wholly of the right kind of causal relations and psychological relations. But then there’s a problem because of course these kinds of relations are ones which can be reduplicated in relatively recherché scenarios and then the thought is but, look, the subject here is clearly not identical to the subject here, so given that this is not identical to this person [referring to board], and there’s no reason to say that this person is identical to this one rather than this one, it follows that this one can’t be identical with that. So it looks like, if there’s this kind of branching, the person here doesn’t end up surviving and Parfit’s answer is, well, that’s fine because although survival is a matter of literally being around at a later time you yourself, in cases of branching it doesn’t matter because actually what matters to us in survival, literal survival, wasn’t that we’re around it’s that there’s some future person-state who’s psychologically related to us in the right way. So Parfit says: in such a situation I’m not around later, but that doesn’t matter because what mattered to me wasn’t whether I’m around but whether there’s some future state which is psychologically related to me in the right way.

4. And Lewis comes along and wants to have his cake and it. And that’s why he says, look, you’re not comparing like with like. It’s person-stages between which the R-relation, the psychological relation holds, and it’s persons who’s identity your concerned about. And persons just are the maximal aggregates of person-stages. And so it just falls out of this view that at this earlier time there are two people and they both survive. And if you want to know what the analogue of identity is for person-stages, it’s what he calls the I-relation. So this stage and this stage [referring to board] are I-related just in case they’re stages of one maximal aggregate of person stages. And so Lewis says, look, I can have my cake and eat it. Parfit says that what matters is being R-related to some future person but for Lewis person stages are R-related just if they’e I-related, just if there is some person that the two person-stage are person-stages of. And Lewis thinks that my desire to survive, for there to be someone to be me, just is the thought that there is some future stage which is I-related to my current stage.

5. So Parfit says that’s not true because, okay, we’ve got it here, right [referring to board]. C1 is such that they have a person-stage at t1 which is I-related to their current person-stage but C1 doesn’t survive. So Parfit points out, look, there’s a difference. And it’s at that stage that Lewis retreats and says, well, that’s fine but because there are two here they couldn’t have the thought “I want to survive” anyway because they can’t have the thought “I”, they can’t have “I”-thoughts. So that’s the context in which Lewis ends up saying this kind of thing. So, why does he say it? Simon says something about the identity theory. The general framework that Lewis operates with is, you know, let’s suppose that at this point in time C1 and C2 are sitting. And the thought is, look, it’s true of C1 that they’re sitting at this time because they’ve got a person-stage which is sitting-shaped. So the thought is that C1 and C2 have a thought at this time just because they have a stage which is having a thought. So, I think Lewis is wrong to say C1 and C2 have to be understood as having the same thought; you can see why it’s quite natural to say, well, the flat-footed way of thinking about how continuants have properties at a time is by their parts having that property.

6. I’ve got two objections to make about the proposal that Simon has given us. I think in this situation it’s quite natural to say that C1 can think- that two people can have different thoughts by thinking “I will survive”. And the utterance for C1 is false and the utterance for C2 is true, because of the way the indexical works. There’s a nice example of Mark Heller’s which is [writes on board]. We naturally read this token ‘this’ as referring to two different sentences as it occurs in this grid. And when Simon said this has been discussed, actually Mark Johnston advocates saying exactly the kind of thing that Simon and David want to say in response to the Lewis-Parfit debate. Okay, I think this works fine but how is it going to work at the level of worlds? So this is the problem. In the Parfittian case where we’re saying that persons are maximal aggregates of stages I think it’s fine that this stage refers to this person. But now what Simon wants is that there’s some future branching when these persons are no longer around and he wants the plurality of persons existing at this time to be a function of stuff right over there and what these ones are referring to to be a function of branching right over there and I think it’s that kind of thing – okay, you can say it and you can get the sentences to work, so you’ll get the sentences to come out right but it seems to me that it’s doing grave violence to the kind of metasemantic principles that John Hawthorne mentioned. And, very briefly, you have the three ways Lewis said we could go, I take it his third one was your fall-back option. I’d recommend that one to you.

Butterfield
7. ….The accidental intrinsics….you said not to worry.. [paper-shuffling] …I think the problem of temporary.intrinsics that…..analogue that ..Lewis…against the believer in…in the endurance advocate that got replied to and surely an analogous thing could be said in defence of overlap in respect to accidental intrinsics. The other thing that……….isn’t it true to say that Belnap had a book…advocacy of overlap rather than divergence? I think Belnap and a Chinese co-author on kind of the best logic of branching.

Saunders
8. Did they use this semantics?

Butterfield
9. I don’t know……..focussed against this divergence advocacy

Saunders
10. Thank you.

[new question]

Greaves
11. This is a clarificatory question. I’m not very clear on why you characterise your position as being one of overlap rather than divergence. One of the slides that you put up characterised an overlap view as being a view in which objects are literally present in more than one world. What are the objects that are literally present in more than one world? I mean it’s not the table, it’s not the rainforest, what is it?

Saunders
12. Well, I think that from the physical point of view it’s clear that we’re dealing with overlapping worlds. That’s surely uncontentious. What I’ve been doing is talking about ordinary semantics, okay, and I’m concerned with truth conditions cashing out ordinary platitudes as true. I’m not concerned with cashing out theoretical talk about what is the fundamental theory of the universe. So, at that level, it is transparently the case that we’re dealing with a branching structure.

Greaves
13. So is it that you deny that this condition that was up in that quote is a necessary condition for there to be overlap? That “there are objects that are literally present in one world” condition.

Saunders
14. That’s how metaphysicians cash out their metaphysical picture, right. From the point of view of the fundamental physics I’m cashing out overlapping worlds in terms of something like decoherent history stages?..blah, blah, blah. Parallel to that I’m giving the semantics for ordinary talk. Now, you’re asking me: is there going to be, consistent with that semantics, an ordinary-talk way of saying I’m living in a branching, overlapping set of worlds, right. And I guess I’m saying probably not.

Loewer
15. ….it seems to me that…what I will say before the branching……[very faint plus background noise]…..what someone else will see, someone else who’s coincident with me, will see the other result. So I don’t see how if somebody was puzzled by how it could be that there’s………………….The other view already has an answer……….but if it doesn’t I don’t see how this helps at all.

Saunders
16. Well, I myself am not clear on to what extent this will provide a different sort of answer to the evidential problem. But it does seem to me that it provides an answer to what we want to say about evidence to a believer in Everett. Someone who believes in Everett, it seems to me, and who sees this ordinary talk as not having deep metaphysical truths – I think it allows one to say all those standard things, you know, I’m going to see one thing or another and I don’t know what and so forth. It doesn’t convict people of some weirdly strange things that they have to say. Now, how it goes with?..someone who does not believe Everett who wants to know what would count as evidence for Everett if it’s true…..believe it to be true, I’m not sure.

Wallace
17. ………uncertainty in this situation…...[indistinct]…..there’s lots and lots of uncertainty in this situation. It’s not ..itional uncertainty but it’s not sort of analogous to………………………..it’s just straightforwardly: I don’t know which one of these guys I am…………………………….

Pooley
18. I don’t think it is merely self-locating uncertainty, apart from the sense that all uncertainty is self-locating uncertainty when you become a modal realist. But it seems to me that Simon wants to say, look, the apparatus is splitting but I, me, am referring to a unique apparatus and so I don’t know whether that apparatus is going to measure spin-up or spin-down but there’s a fact of the matter about which it measures.

Wallace
19. ….I have no interest whatever in using the Everett branching structure to do modal talk….physics.. If modal metaphysicians say, ah, fantastic, the Everett universe is just what we wanted, then that’s great but I have no credence at all in the fact that we’re required to use this………

Saunders
20. Could I just interject, if you are interested – Here’s what McDaniel..says: ‘it is possible that Al Gore won the 2000 US presidential election’ must include in some intimate sense the object the claim is about…So here’s what one can say as an Everettian: Al Gore could have won the 2000 US because part of him was a part of an Al Gore who did win the 2000 US presidential election. And I don’t know if that’s intimate enough but I don’t actually care either whether this is acceptable or not so..

Pooley
21. I don’t think my claim was modal at all. There’s a fact of he matter that that apparatus that it will either measure spin-up or it will measure spin-down. There are lots of different apparatuses but I, on Simon’s picture, am able to see and refer to only one. I don’t understand how that is, but that’s the claim. And so I don’t know which of the outcomes is true but – so that seemed like a non-modal claim.

[new question]

Papineau
22. I want to press on to utterances and why Lewis …..[indistinct]……and you want to say that Lewis doesn’t, that before?..there’re two utterances…………………Isn’t there a much simpler answer? So people are maximal worms of stages that are people-wise related and they look at this structure and there’s clearly two people there. Utterances are, let’s say, maximal……of stage that are utterance-wise related and…The point is utterances are much shorter. So if you look at that structure before the branch and count how many utterances there are there’s just one. And I don’t see how you get two. Now you said they enter into different causal relations but that’s begging the question. You’ve got to show me there’s two. I see one and that one enters into just the same causal relations.

Saunders
23. No, no, it doesn’t enter into the same causal relations it’s just that, look – what was before, it’s over, it’s finished. That was reassuring to the one person; it was not at all reassuring to the other person, it was a declaration of despair, it had a different causal role – this is Peter and Colin and the cat and so forth [ref. to final part of Saunders’ talk]. So it has different causal roles. But as to the issue of why are there two, the point is that if utterances are attributed to persons, okay, then this person says an utterance, this other person says an utterance, and what is he meaning of the utterance, what is the role of that utterance in those persons’ lives and so forth, the point is it has different content.

Papineau
24. Sure, I can attribute utterances to persons, no great trouble there, but if there’s just one utterance attributed to both of them then you get, like Lewis, it’s not going to have a determinate reference and so on……You still haven’t got two utterances, it seems to me.

Saunders
25. Is your point that it doesn’t follow from attributing utterances to persons that the word ‘I’ refers to a unique person?

Papineau
26. …..that there’s two utterances and now we have one utterance and now we start thinking about the semantics of that utterance and since ‘I’ I understand to refer to people and there’s two people here I just….

Saunders
27. But that flatly contradicts he presupposition that utterance is attributed to a unique person

Papineau
28. ..you can attribute to me an utterance with indeterminate reference…

Saunders
29. I can attribute to you an utterance with indeterminate reference but the point is in this case I am not doing so. Is the account, then, better filled out by saying ‘I’ is to refer to a unique continuant. Utterances are to refer to unique continuants, the word ‘I’ in an utterance is to refer to the utterer, that unique person that utters it?

Papineau
30. ……the presupposition that you’re entitled to posit two utterances, that’s all.

Rae
31. My belief is that if there are two thoughts in S then C2 must be unaware of the thought related to C1 and I can’t see how you can have two thoughts in S and have C2 completely forgetting that they previously had the thought which is relative to C1.

Williamson
32. A couple of things. One is that the motivation that you seemed to be offering people was at least in part that it was a way of preserving bivalence, which you lost if you didn’t do this, as it were ….into two worlds. But it isn’t the only way of preserving bivalence. You could have a view on which the truth condition for ‘it will be the case that P’ is, roughly speaking, that P has the whole……branch’ (from where you are) and that doesn’t loose you bivalence, even assuming that you associate falsity with truth of the negation, you just have to be very careful about the relative scope of negation and the future tense operator. And so you’ll have cases where ‘it will be that P’ will come out as not true and ‘it will be that not-P’ will also come out as not true, but ‘not – it will be that P’ will come out as true and so you can get bivalence that way. And I think in some ways that’s actually more hospitable to bivalence than the way you’re going because I think it will be very hard to resist the idea that some coarse-grained sense of utterance, in addition to the one that you’ve got, in which there’s only one utterance there and as soon as you try to assign a truth value to that single coarse-grained utterance you’re probably going to find yourself finding it very hard to resist saying some kind of supervaluationist thing which will mean a failure of bivalence.

33. The other minor thing was, I didn’t really understand the play between truth and justification – I mean I don’t really see how you could be taking justification as a fundamental notion of the semantics because I think it likely to run into trouble with the semantic rules for negation. Maybe you’re not, but if you are then I think you need to tell me what the semantic rule for negation is.

Saunders
34. Well, I wasn’t aware that this would be a critical issue. If it is, I’d be very surprised if this is going to be a significant problem.

Williamson
35. Are you taking justification as basic?

Saunders
36. No.

Williamson
37. So the semantics isn’t actually given in terms of justification it’s given in terms of truth.

Saunders
38. No, no.

Williamson
39. Okay, so that was just, as it were, some extra twiddly bit that you stuck on.

Saunders
40. Well, in so far as we – many people here are very preoccupied with the question is there a place for uncertainty, in what sense is one justified in saying “I am uncertain about the future” in an Everettian branching world. I just wanted to give a justification, a sense in which one is indeed uncertain.

Williamson
41. ………semantics in terms of justification or truth?

Saunders
42. Okay…

Williamson
43. That was a slip, was it?

Saunders
44. Yeah……set out then it is going to be a detailed semantics, no, I would not proceed in terms of justification, no.

[new question (observation)]

Bacciagaluppi
45. I wanted to support Simon using an analogy I think – this is now Wayne supporting Simon. Okay, what you’ve showed us, what you want to do is – we’ve got one and the same universal wave function and we’re going to look at it in different ways. Spin-up, spin-down…………we’re going to look at that as spin-up……..and spin-down…………there’s no metaphysical difference but the second is more serviceable when you want to talk about semantics. And what I think is a fairly good analogy is what happens when we have………..measurement, not in our future but at spacelike separation. The question whether we should consider that this measurement at spacelike separation is ……..branching of us over here. And what I take Wayne to say is that we are free to think of branching as happening along any hypersurface, spacelike hypersurface that contains the……….and all of those are equally good ways of thinking of the universal wave function and that’s perfectly analogous, ergo we might think of the distant spacelike measurement as not inducing a branching of ourselves over here……..until our world-line crosses the future light-cone of that measurement or we could just look at it along any kind of surface we want…………..that measurement is in the past or simultaneous with us now and we do, we are branching due to that measurement – and they’re all perfectly good ways of looking at the wave function…… if they are in that situation they are also….

[new question]

Lewis
46. I’m a bit unsure about seeing why the thought ‘I will survive’ has two causal roles. I mean, ……end up in two persons…………

Saunders
47. I think in that particular example the one that dies is dying rather quickly isn’t it. What is the causal role of this sentence here [ref to screen]? Say it’s a promise, a promise……girlfiend…….What is that promise? What is the status of that? What is the role of that speech act in this situation?

Lewis
48. None.

Saunders
49. None? Oh, she says “You lied to me, you said you would survive”. It was a lie.

[new question]

Lehner
50. I think this is a combination of what’s been said before. I rather like you fall-back position and so I was trying to understand why you thought that’s more than a fall-back position and what’s so bad about not having bivalence? It seems that was your main argument – especially in the context of quantum mechanics of course.

Saunders
51. I don’t want to criticise my fall-back position.

[new question]

Sudbery
52. I’ve got a question for two Simons, Simon the organiser and Simon the speaker. It may be that the honourable thing for Simon the organiser to do would be to tell Simon the speaker not to answer. In your introductory talk you had a nice slogan, which I thought you were going to talk about today, that is: we expect what we remember. It’s distinctly relevant to your title..probability. Have you anything to say about that?

Saunders
53. What is the dialectical position here? It seems to me that I am under some coercion here, and I think we all of us always are. Coercively we expect more?..and this is our Humean predicament. And in a sense that ought to be enough. What else can I do? I can only expect what I’ve had before, I can only expect more of the same. Against that there’s another sort of coercion, a coercion of reason which says, no, look, look at these reasons why you cannot expect more of the same. And insofar as you were thinking anything like this before you were just wrong then too. So that’s another sort of coercion. And it seems to me the issue is this, the right onus here. Is there a defensible sense, an intelligible, transparent, clear sense in which I can say I don’t know what’s going to happen, given Everett? And this talk is all about: here’s a defensible sense in which I can say I’m uncertain about the future. So it is, as it were, a defense of and removes – there’s two different coercions here – it allows that coercive Humean habituation stuff to work as it ordinarily does. And part of my problem with why (I’m now going to speak against my fall-back position) – a part of the problem, it seems to me, with the fall-back position – well, it doesn’t address the point that the – actually, no, I’m not going to argue against my fall-back position.

[new question]

Hawthorne
54. I’ve got a couple of quick things to say about the relation between self-locating belief, uncertainty and probability. I think firstly ………..it’s often ignored but in this setting it is important, the methodogical situation before we look at the Everett stuff is, when you pay a bit of attention, one in which, crucially, we recognise that for self-locating beliefs with indexicals the Principal Principle breaks down. We knew that already so lets ……….take claims of the form: contingent propositions of the form ‘p if and only at …’..our credence is one. Objective chance isn’t hyperintentional it’s intentional so the objective chance of the proposition expressed by that claim is known to be less than one. And so the self-locating aspect of the actual indexical makes a total mess of the Principal Principle. Well we knew that already, so we aren’t in a situation where we want credences to track the Principal Principle, we’re in a situation where for self-locating beliefs we know that they should track objective chance. That’s the situation, the pre-physicsy situation, and I thought it was very misleading that that’s been dropped out?...

55. A second thing that I think’s very important is to see how some of these Adam Elgar discussions interact with your semantics, so take a case where you go, there’s three-way fission with half, quarter, quarter weights into three subjectively identical duplicates at a later time. So, there’s a bunch of philosophers that have argued, and they seem to be winning, that at that later time you have uncertainty as to who you are and your credences should go third, third, third across the three de se possibilities. The principle they’re going with is distribute your credences evenly across de se duplicate possibilities within your world, and have argued that there’s a…….winning. If you tack on your metaphysics and semantics to that principle then what you get is the result that even before the splitting you should be third, third, third as between who you are by the Elgar principle and so then crucially your self-location hypotheses and credences about them won’t match at all the branch weights. So it’s absolutely vital to you, if you’re going to go with that package, to argue the growing orthodoxy as to how credence should function with regard to de se beliefs in duplication scenarios is wrong.

Saunders
56. I don’t agree with that latter point. I think your former point is very interesting, I need to understand that better, but the latter point, I don’t agree. It seems to me that the Everett interpretation and this sort of issue has very little to do with the Sleeping Beauty stuff.

Wallace
57. ……………

Saunders
58. That would be a very quick reply. But, look, I understand, one needs a whole presentation on this. But I think, in general, the right thing to say is the way these things have been debated in a lot of contexts in philosophy is rather sensitive to issues that are really flatly denied in the Everett interpretation. And you need to see how in each case that checks out. I think the issue of no determinacy in branch number already just makes nonsense of any attempt a la thirders to work out probabilities in these counting ways. That should be obvious, I mean, have Sleeping Beauty wake up a hundred times, what’s the probabilities then?

Hawthorne
59. If you think you can escape from the Adam Elgar framework just by having vagueness in the specifications?..of who you are and vagueness – that’s just not going to work out. To think that the thirder approach is going to vitiated?..by vagueness…….

Saunders
60. John, she wakes up a hundred times what’s…

Hawthorne
61. I’m interested in the Elgar discussions as applied to classical fission cases.

Saunders
62. But this isn’t being applied to classical fission cases.

Hawthorne
63 – Okay, but let’s start there. So the orthodoxy has it that you go a third a way in a classical fission. And I think once you go with Elgar on that, and I know you’re adding in extra tweeks, you’re adding indeterminacy of branching and this and that but I think it becomes very hard to resist being a thirder in this situation. It becomes unclear what the extra elements of vagueness are doing to really disrupt the thirder arguments. So then it’s going to be a mess if you have three de se possibilities before branching.

[new question]

Albert
64. I guess this is an attempt just to press Barry’s question and sort of John’s question a little harder. I didn’t see how all the problems went away when David said, no, it’s as clear as can be. Look, I’m sorry, I’m being muddled and inarticulate here and I’m just groping to try to understand it and maybe at bottom just pleading for help. But let me raise it on several levels. Level one, and this is probably just exposing that I don’t really understand, this is not a critique this is a confession that I don’t fully understand what’s at stake in this……discussion. If the discussions really are supposed to have semantical but not fundamental metaphysical import, if they’re just supposed to show how speaking in a certain way about a fundamental metaphysical structure on which we’re all agreed could make sense, okay, then I don’t know why I’m not justified in thinking about these problems about probability and so on and so forth in just ignoring them. In just saying, look, I understand the other structure, I understand the fundamental metaphysical structure, I think I see how things go there, it just seems like it could be held to be completely irrelevant to that discussion that there is another coherent way of mapping this onto our ordinary language. So, that’s one level of confusion, and like I say I’m very ready to be instructed here as to how I’m just misunderstanding the import of what’s at stake in the semantical discussion.

65. The second level of confusion, which I guess is the one which Barry was pressing, is: even if the semantical discussion turns out to have more teeth than I’m understanding, and even if the semantics somehow establishes not merely that there’s a coherent way of uttering “I am ignorant” or not an insane way of uttering “I am ignorant”, but that I really am ignorant in some sense. It’s hard to see, given the fixed metaphysical structure underneath it, how learning what I learn after the branching is going to be a way of learning about the fundamental metaphysical structure of the world in a way that’s going to allow me to distinguish between two dynamics that, say, assign different amplitudes to the same branches. Okay, so that’s an unfairly long and multi-part question.

Saunders
66. Let me say a couple of words but perhaps, David, you’d like to say something too. Just to your first point, it seems that when you say metaphysics I have to translate to physics.

Albert
67. Yeah, fine.

Saunders
68. And what I think you come back to as a way of rejecting this semantics and so forth is still a metaphysical view and it’s a metaphysical view, I think, which is essentially a stage-theorist view. I mean I think you’re a Siderian stage theorist in the Everettian case. And okay, you know.

Albert
69. Simon, look, I’m wondering about things like how this semantics system?..is suddenly making …[noise]…the amplitudes explain..

Saunders
70. Oh sure, but that’s coming to the second question. On the second point, what I’m discovering by doing experiments and so forth is what happens in my world. That’s what I’m discovering. I hope my world is typical, it may not be typical, I may get deviant outcomes.

Wallace [addressing Albert]
71. I think your second point is…..[indistinct]……..if the first point goes through………..the ordinary-language-stated set of rules we have…………map onto the theory in the normal way. If they map onto that theory……………………………………..

Tappenden
72. Okay, well, there’s a link on the site to a paper I’ve written against this argument but David and Simon have heard my objection to it many times so I’ll try to put it slightly differently. But I should say that on the site it’s listed under anti-Everettian arguments and I don’t see it as that, I’m very much and enthusiast for Everett, I just think there’s a problem with this argument. Perhaps David Papineau was indicating a different way to put a point similar to mine, I don’t know. This is the way I’d put it now. We’re in this situation of overlap which is very unusual. We’re considering multiple utterance on a single token and who they’re attributed to. So we should at least be cautious about what we’re assuming about the way utterances refer. Especially in the case of the utterance of ‘I’ and the point that I’ve been harping on about and which wasn’t clear in Simon’s talk is that you’ve got to distinguish beween attributing an utterance of ‘I’ to a speaker, okay, so if we allow that there are two utterances coinciding in one physical vocal event, we’re going to attribute one utterance to one speaker and one utterance to the other. It’s another thing entirely what the referent of that term is going to be. So it seems as if Simon and David want to help themselves to the assumption that you can attribute an utterance of ‘I’ to the person seeing outcome A and the reference of their utterance of ‘I’ to that person as well so that you can allow that person to succeed in referring to themself. My whole argument is that there’s good reason to suppose that actually the indexical reference breaks down in this situation and we cannot suppose that the utterance of ‘I’ does succeed in self-referring. So in that case saying “I don’t know which person I am” doesn’t make sense because I can’t even say that my utterance of ‘I’ refers to the person it’s supposed to be referring to – it doesn’t get off the ground.

Saunders
73. A brief comment. The way I understand this sort of criticism is: here’s a condition that is in place in non-branching scenarios, namely where a local bit of physics will uniquely pick out the unique continuant and that isn’t the case in a branching situation. But I think to insist that has to be in place, that some local bit of physics has got to, as it were, causally connect uniquely with – and so forth. I think it needs a lot of argument for that principle to achieve the kind of seriousness that it needs to have. Because, to say again, this is not the claim that here’s the most natural or correct metaphysical analysis and and so on and so forth. It’s to say: here is a simple and consistent and intelligible semantics. Now there’s no ambiguity in this semantics. I think there’s a tacit suggestion that there’s some ambiguity, but there is no ambiguity in this semantics. There’s simply lack of self location.

Tappenden
74. Well, I’d just like it to be clear in the argument that you are helping yourself both attributing an utterance to a speaker and to taking the referent of that utterance to be the speaker as well. And they’re two distinct things. I just want it to be clear – okay, people might grant you that you can make those two assumptions and it’ll work, but people might….

Saunders
75. Right, but let’s be clear on what those assumptions are then. It is that utterances are attributed to unique continuants [speakers], and an utterance of ‘I’ is attributed to the speaker.

Tappenden
76. Attributed to the speaker is one thing, whether it refers to the speaker is another.