Robbie Williams has a response to my post Against 'Against Vague Existence' over on his blog Theories 'n Things.
I've recently written up a short note based on the idea in my original post, which I've put online here. I hope it goes some way to addressing Robbie's concerns (which centre on the thought, shared by Sider, that I need to say something about what kind of thing a precisification is on the envisaged account).
Thursday, June 29, 2006
Wednesday, June 28, 2006
Extended Simples and Quantized Space
David Braddon-Mitchell and Kristie Miller have a fun new paper arguing that we can both believe in spatially extended mereological simples and agree that every extended object o has a part at each sub-region of the region which o occupies. The trick which is supposed to enable us to marry these two theses is to claim that space has smallest regions which have no sub-regions. (This is a position I've heard defended in conversation by others as well, so I'm coming round to the view that it ought to be taken seriously.)
For many of us, quantized space seems a very strange idea on the face of it, but Braddon-Mitchell and Miller argue that it must be taken seriously because of certain results in physics. They claim that 'physicists tell us that we cannot divide up space into any finer-grained regions than those constituted by Planck squares [i.e. areas of 10 to the power -66 centimetres squared]' and that physics 'tells us that talk of space breaks down altogether once we talk about regions smaller than the Planck square'. 'Hence', they conclude, 'we know that talking about something occupying a sub-region of a Planck square makes no sense: there is no such sub-region' (p. 224).
When they give a few details of what the physics actually shows, it turns out to be that 'there is nothing that could be taking place within these squares'. Braddon-Mitchell and Miller take it (and this is where I get puzzled) that this 'is to say that in principle, there cannot be anything that occupies the sub-regions of such a square' (p. 224, their emphasis).
For all I know, physicsists may well be claiming this sort of import for that sort of result, but I can't see how the transition could be that straightforward. What I can't understand is how any claim about what can or cannot take place with a Planck square - which is of course the sort of thing physicists can helpfully tell us about - could settle the question of whether such a square has sub-regions. Specifically, I wonder what sort of results are supposed to distinguish between the hypotheses:
1. that Planck squares have no sub-regions
and
2. that any Planck square (and therefore any sub-region of a Planck square) must, as a matter of nomic necessity, be uniformly filled.
The claim that nothing can be 'taking place' within a Planck square seems at best to get us as far as 2. What justifies the further step to 1? What sort of result from physics as it is currently practiced could possibly justify this further step?
(I ask these questions in self-confessed ignorance of the physics, but with a dose of scepticism as to whether we can get this much metaphysics out of it, whatever it is!)
For many of us, quantized space seems a very strange idea on the face of it, but Braddon-Mitchell and Miller argue that it must be taken seriously because of certain results in physics. They claim that 'physicists tell us that we cannot divide up space into any finer-grained regions than those constituted by Planck squares [i.e. areas of 10 to the power -66 centimetres squared]' and that physics 'tells us that talk of space breaks down altogether once we talk about regions smaller than the Planck square'. 'Hence', they conclude, 'we know that talking about something occupying a sub-region of a Planck square makes no sense: there is no such sub-region' (p. 224).
When they give a few details of what the physics actually shows, it turns out to be that 'there is nothing that could be taking place within these squares'. Braddon-Mitchell and Miller take it (and this is where I get puzzled) that this 'is to say that in principle, there cannot be anything that occupies the sub-regions of such a square' (p. 224, their emphasis).
For all I know, physicsists may well be claiming this sort of import for that sort of result, but I can't see how the transition could be that straightforward. What I can't understand is how any claim about what can or cannot take place with a Planck square - which is of course the sort of thing physicists can helpfully tell us about - could settle the question of whether such a square has sub-regions. Specifically, I wonder what sort of results are supposed to distinguish between the hypotheses:
1. that Planck squares have no sub-regions
and
2. that any Planck square (and therefore any sub-region of a Planck square) must, as a matter of nomic necessity, be uniformly filled.
The claim that nothing can be 'taking place' within a Planck square seems at best to get us as far as 2. What justifies the further step to 1? What sort of result from physics as it is currently practiced could possibly justify this further step?
(I ask these questions in self-confessed ignorance of the physics, but with a dose of scepticism as to whether we can get this much metaphysics out of it, whatever it is!)
Tuesday, June 27, 2006
Job News
I've just accepted a job offer from the University of Nottingham. I start there on 1st September, although I will be in Australia until September 2007.
My favourite colleague is also moving to Nottingham. We are sorry to leave behind lots of great colleagues in St Andrews, but are very excited about joining the Nottingham crowd!
My favourite colleague is also moving to Nottingham. We are sorry to leave behind lots of great colleagues in St Andrews, but are very excited about joining the Nottingham crowd!
Monday, June 26, 2006
Philosophy of Flirting
Just for fun, I've written up a few thoughts on the philosophy of flirting. I'm trying to make progress towards a set of necessary and sufficient conditions for when an act of flirtation has taken place. Let me know what you think!
Wednesday, June 21, 2006
TAR at new address
For those who read Brian Weatherson's blog as well as this one (I imagine an improper subset of those who read this blog), Thoughts Arguments and Rants is now at http://tar.weatherson.org/ after the original address was hijacked.
Sunday, June 18, 2006
They'll All Be Concept-Grounding Theorists Soon ...
More evidence that a priori knowledge is hitting the big time again - and that people are starting to ask just the right sorts of questions about it (that is, the questions that motivate my view ... :)
Saturday, June 10, 2006
Infallibility and Modal Epistemology
The Arche Modality Conference has just finished, and has been excellent fun. I've put some photos on my website. In the end, my comments on Scott Sturgeon's talk mainly focussed on the claim that the infallibility of idealized conceivability methods is the wrong focal point for his worry. He's worried that if we are realists, we shouldn't think that metaphysics and epistemology will fit together the way the infallibilist requires - there should be room to make a mistake. For idealized conceivability (as he thinks of it) involves only mental idealization (allowing unlimited time, capacities etc.). How can we have a guarantee of getting a true belief, if we have only idealized these mental processes, and said nothing about their relationship to the world?
But I argued that we still have a worry of the same kind for fallibilist conceivability views. My point here was just an analogue of what we tell students who think Hume’s worries about induction show that we aren’t guaranteed to get true beliefs by inductive methods, but still think these beliefs are likely to be true. What I claimed is that, for the same reasons Sturgeon thinks we should be worried about the infallibility of conceivability, namely because epistemology and realist metaphysics don’t fit together like that, we should also be worried about the claim that it’s likely that conceivability will deliver true beliefs. Epistemology and realist metaphysics don’t fit together like that either – you don’t get good ways of finding out about the independent world when you idealize along only mental dimensions. Good ways of finding out about the independent world require input, which is a world-involving relationship, and not purely mental.
So infallibility is not necessary to generate the problem. In fact, I claimed, it’s not sufficient either. Sturgeon’s worry will go away if we can somehow add a mind-world input element into our account of ideal conceivability. This sort of ideal conceivability can unproblematically be infallible, for the same reasons Sturgeon thinks idealized vision (which is, among other things, always veridical) can unproblematically be infallible.
The deep problem in the vicinity of Sturgeon's worry is a very old one: how can a priori reflection be a source of knowledge of facts which are construed realistically? But of course, there are many answers to this and debates about them which would have to be engaged with before we could claim to have pressed the point in a new way.
But I argued that we still have a worry of the same kind for fallibilist conceivability views. My point here was just an analogue of what we tell students who think Hume’s worries about induction show that we aren’t guaranteed to get true beliefs by inductive methods, but still think these beliefs are likely to be true. What I claimed is that, for the same reasons Sturgeon thinks we should be worried about the infallibility of conceivability, namely because epistemology and realist metaphysics don’t fit together like that, we should also be worried about the claim that it’s likely that conceivability will deliver true beliefs. Epistemology and realist metaphysics don’t fit together like that either – you don’t get good ways of finding out about the independent world when you idealize along only mental dimensions. Good ways of finding out about the independent world require input, which is a world-involving relationship, and not purely mental.
So infallibility is not necessary to generate the problem. In fact, I claimed, it’s not sufficient either. Sturgeon’s worry will go away if we can somehow add a mind-world input element into our account of ideal conceivability. This sort of ideal conceivability can unproblematically be infallible, for the same reasons Sturgeon thinks idealized vision (which is, among other things, always veridical) can unproblematically be infallible.
The deep problem in the vicinity of Sturgeon's worry is a very old one: how can a priori reflection be a source of knowledge of facts which are construed realistically? But of course, there are many answers to this and debates about them which would have to be engaged with before we could claim to have pressed the point in a new way.
Monday, June 05, 2006
Responding to Kripke
Right, I'm back ... minus one appendix. And straight back into the thick of it, with the Arche academic audit starting today. We've had talks by Mark Sainsbury, Paul McCallion, Philip Ebert and Marcus Rossberg (jointly) and Frank Jackson, with topics ranging from famous fictional characters such as Sherlock Holmes to infamous real ones such as Julius Caesar and Timothy Williamson.
In my spare time :) I'm meant to be preparing some comments on Scott Sturgeon's talk at the upcoming Modality Conference, which is based on this paper. He is arguing against the following combination of views:
1. Kripke is right that ideal conceivability does not imply possibility.
2. But we should make minimal adjustments to deal with 1 - i.e. we should hold that ideal conceivability implies possibility except in the particular kinds of case Kripke brings to our attention.
One thing I'm not sure of is whether this combination of views is defended in print by anyone. (Scott doesn't mention anyone in the version of the paper I've seen.) But more interestingly, I wonder whether many people really (perhaps tacitly) think this is the appropriate thing to do.
In my spare time :) I'm meant to be preparing some comments on Scott Sturgeon's talk at the upcoming Modality Conference, which is based on this paper. He is arguing against the following combination of views:
1. Kripke is right that ideal conceivability does not imply possibility.
2. But we should make minimal adjustments to deal with 1 - i.e. we should hold that ideal conceivability implies possibility except in the particular kinds of case Kripke brings to our attention.
One thing I'm not sure of is whether this combination of views is defended in print by anyone. (Scott doesn't mention anyone in the version of the paper I've seen.) But more interestingly, I wonder whether many people really (perhaps tacitly) think this is the appropriate thing to do.
Wednesday, May 24, 2006
Out of action
LWBM will probably be off air for a little while; due to illness I will be off work until at least the end of May.
Wednesday, May 17, 2006
Going to Australia
I'm very pleased to be spending the next (British) academic year on secondment at the ANU. I'll be working on an ARC project, Epistemic Warrant, lead by Daniel Stoljar, Martin Davies and Crispin Wright. The project will focus on transmission of warrant, basic knowledge and entitlement.
Wednesday, May 03, 2006
Dogmatism and The Content of Experience
If I understand correctly (and I'm indebted to Sebastian Schmoranzer's recent Arche presentation for clarifying the following exegetical points) it is a tenet of Pryor's dogmatism (as represented in this paper) that certain of my experiences give me a reason to believe I have hands, and this regardless of any antecedent warrant I may have for thinking that I am not hallucinating, not a brain in a vat, etc.. Why? Because my experience represents it as being the case that I have hands.
However, my experience's 'representing it as being the case that I have hands' cannot amount to its being as it would be if I had hands, lest we be able to construct a parallel argument to the effect that experience gives me a reason to believe I am a brain in a vat being fed perfectly hand-like sensations.
The standard response to this seems to be that although my experience is as it would be if I were that kind of brain in a vat, my experience does not represent it as being the case that I am that kind of brain in a vat in the way it represents it as being the case that I have hands. That is, the content of my experience is that I have hands, not that I am a brain in a vat having hand-like experiences.
This seems to raise a puzzle: how do we spell out the notion of content required? If it is purely something about (my relationship to) the external world that makes the difference between having an experience with content 'I have hands' and having an experience with content 'I am a brain in a vat having hand-like experiences', then the 'standard response' just described appears to collapse the dogmatist line into a familiar kind of disjunctivist response to scepticism.
On the other hand, suppose we try to use inferential role (assuming that to be something internally accessible) to distinguish the two contents. Then the important thing about the inferential role of the content of the experience I'm actually having is presumably going to include things like the fact that I can correctly infer from the content of this experience to the conclusion that I am not a handless brain in a vat, which is something I cannot infer from the content of an experience which represents it as being the case that I am a brain in a vat having hand-like experiences.
However, it seems to be blantantly begging the question against the sceptic to assume without further comment that I am presently having an experience the content of which enables me to correctly infer that I am not a handless brain in a vat. This is exactly what the sceptic doubts my experience is like.
So what other stories about the difference in content are available for the dogmatist to tell here?
However, my experience's 'representing it as being the case that I have hands' cannot amount to its being as it would be if I had hands, lest we be able to construct a parallel argument to the effect that experience gives me a reason to believe I am a brain in a vat being fed perfectly hand-like sensations.
The standard response to this seems to be that although my experience is as it would be if I were that kind of brain in a vat, my experience does not represent it as being the case that I am that kind of brain in a vat in the way it represents it as being the case that I have hands. That is, the content of my experience is that I have hands, not that I am a brain in a vat having hand-like experiences.
This seems to raise a puzzle: how do we spell out the notion of content required? If it is purely something about (my relationship to) the external world that makes the difference between having an experience with content 'I have hands' and having an experience with content 'I am a brain in a vat having hand-like experiences', then the 'standard response' just described appears to collapse the dogmatist line into a familiar kind of disjunctivist response to scepticism.
On the other hand, suppose we try to use inferential role (assuming that to be something internally accessible) to distinguish the two contents. Then the important thing about the inferential role of the content of the experience I'm actually having is presumably going to include things like the fact that I can correctly infer from the content of this experience to the conclusion that I am not a handless brain in a vat, which is something I cannot infer from the content of an experience which represents it as being the case that I am a brain in a vat having hand-like experiences.
However, it seems to be blantantly begging the question against the sceptic to assume without further comment that I am presently having an experience the content of which enables me to correctly infer that I am not a handless brain in a vat. This is exactly what the sceptic doubts my experience is like.
So what other stories about the difference in content are available for the dogmatist to tell here?
Thursday, April 27, 2006
Against 'Against Vague Existence'
In 'Against Vague Existence', Ted Sider argues that our quantifiers cannot be vague, because it is impossible to characterize semantic vagueness in our quantifiers in the usual way; that is, in terms of multiple admissible precisifications. Sider considers as a test case whether it could be indeterminate, due to vagueness in the existential quantifier, whether the following was true:
(E): Ex (x is composed of the F and the G).
Sider claims that the ‘familiar model’ for spelling out how such indeterminacy comes about would apply to this case as follows:
(P1): ‘E’ has at least two precisifications, call them E1 and E2. There is an object, x, that is in E1’s domain but not in E2’s domain, and which is composed of the F and the G. Thus, (E) is neither definitely true nor definitely false.
But, as Sider points out, ‘the defender of vague existence thinks that it is not definitely true that there is something composed of the F and the G ... She will therefore not make this speech’ (p. 139).
Sider proceeds to offer three options to the defender of vague existence: rejecting the need to non-vaguely describe the precisifications, using vague quantifiers to non-vaguely describe them, and finding non-quantificational non-vague language to describe them. None of these is my preferred way of resisting Sider’s argument. Nor do I wish to resist (here) his two presuppositions: that the indeterminacy of (E) would have to be semantic (as opposed to ontic), and that this means we need to explain it in terms of multiple admissible precisifications of the existential quantifier.
Instead, I propose we investigate how much can be achieved through paying careful attention to scope in describing the relevant precisifications. Instead of (P1) above, perhaps we can appeal to:
(P2): ‘E’ has at least two precisifications. On the first precisification, there is an object, x, which is composed of the F and the G. But on the second precisification, there is no such object. Thus, (E) is neither definitely true no definitely false.
Note that, now, the existential quantifiers appearing in the account of why (E) is neither definitely true nor definitely false occur within the scope of the operators ‘on the first precisification’ and ‘on the second precisification’. Hence there is no need for any metalanguage commitment to an object which is composed of the F and the G.
(P2) seems to do what Sider requires: it talks about two precifications for ‘E’, and explains what it is about these two precisifications which results in the indeterminacy of (E). So what’s wrong with (P2)?
(E): Ex (x is composed of the F and the G).
Sider claims that the ‘familiar model’ for spelling out how such indeterminacy comes about would apply to this case as follows:
(P1): ‘E’ has at least two precisifications, call them E1 and E2. There is an object, x, that is in E1’s domain but not in E2’s domain, and which is composed of the F and the G. Thus, (E) is neither definitely true nor definitely false.
But, as Sider points out, ‘the defender of vague existence thinks that it is not definitely true that there is something composed of the F and the G ... She will therefore not make this speech’ (p. 139).
Sider proceeds to offer three options to the defender of vague existence: rejecting the need to non-vaguely describe the precisifications, using vague quantifiers to non-vaguely describe them, and finding non-quantificational non-vague language to describe them. None of these is my preferred way of resisting Sider’s argument. Nor do I wish to resist (here) his two presuppositions: that the indeterminacy of (E) would have to be semantic (as opposed to ontic), and that this means we need to explain it in terms of multiple admissible precisifications of the existential quantifier.
Instead, I propose we investigate how much can be achieved through paying careful attention to scope in describing the relevant precisifications. Instead of (P1) above, perhaps we can appeal to:
(P2): ‘E’ has at least two precisifications. On the first precisification, there is an object, x, which is composed of the F and the G. But on the second precisification, there is no such object. Thus, (E) is neither definitely true no definitely false.
Note that, now, the existential quantifiers appearing in the account of why (E) is neither definitely true nor definitely false occur within the scope of the operators ‘on the first precisification’ and ‘on the second precisification’. Hence there is no need for any metalanguage commitment to an object which is composed of the F and the G.
(P2) seems to do what Sider requires: it talks about two precifications for ‘E’, and explains what it is about these two precisifications which results in the indeterminacy of (E). So what’s wrong with (P2)?
Wednesday, April 26, 2006
Field Motivates Concept Grounding
In his paper 'Recent Debates About the A Priori', Hartry Field seems to me to be spot on the following passage (pp. 13-14 of the online paper):
[T]he key issue is ... : why should the fact, if it is one, that certain beliefs or inferences are integral to the meaning of a concept show that those principles are correct? Why should the fact, if it is one, that abandoning those beliefs or inferences would require a change in meaning show that we shouldn't abandon those beliefs or inferences? Maybe the meaning we've attached to these terms is a bad one that is irredemably bound up with error, and truth can only be achieved by abandoning those meanings in favor of different ones ...
However, I don't agree with Field that this point is a step on the way towards his conclusion, namely that to claim we have an entitlement, at least in the case of 'basic' beliefs or logical rules, is merely to express an attitude of approval toward those beliefs or rules.
Rather, what Field's questions rightly raise to notice is the need for some account of why we should trust the meanings we have attached to our words (or, as I would prefer to say, why we should trust the concepts we express by them) to serve as epistemic guides to the way the world is. That is, we need a story about concept grounding to explain why these meanings or concepts are rightly taken as encoding information about the world which we can recover through introspection.
[T]he key issue is ... : why should the fact, if it is one, that certain beliefs or inferences are integral to the meaning of a concept show that those principles are correct? Why should the fact, if it is one, that abandoning those beliefs or inferences would require a change in meaning show that we shouldn't abandon those beliefs or inferences? Maybe the meaning we've attached to these terms is a bad one that is irredemably bound up with error, and truth can only be achieved by abandoning those meanings in favor of different ones ...
However, I don't agree with Field that this point is a step on the way towards his conclusion, namely that to claim we have an entitlement, at least in the case of 'basic' beliefs or logical rules, is merely to express an attitude of approval toward those beliefs or rules.
Rather, what Field's questions rightly raise to notice is the need for some account of why we should trust the meanings we have attached to our words (or, as I would prefer to say, why we should trust the concepts we express by them) to serve as epistemic guides to the way the world is. That is, we need a story about concept grounding to explain why these meanings or concepts are rightly taken as encoding information about the world which we can recover through introspection.
Friday, April 21, 2006
Beall and the Paranormal
This week I've been thinking about JC Beall's fun paper 'True, False and Paranormal'. Essentially, the idea is to model our truth-talk with a disquotational predicate 'T', and have a language which can exhaustively characterize all its sentences as 'true', 'false' or 'other', without thereby admitting true contradictions. Sentences of the model can take any one of five values, 0, .25, .5, .75 and 1, of which .75 and 1 are designated. A new term 'pi' is introduced (sorry I don't have a pi-symbol here!) to mean 'paranormal' (or 'other'), and pi-A takes the value .75 when v(A) = .25, .5 or .75, and takes the value 0 otherwise.
It seems that the view requires that there is no predicate in the model language like D ('D' for 'designated'), where:
v(D[A]) = 1 or .75 when v(A) = 1 or .75
and v(D[A]) = 0 or .25 when v(A) = 0, .25 or .5
Otherwise the sentence
A*: ¬D[A*]
presents a problem. (It is designated iff it isn't.)
But it seems to me that such a predicate is needed in order for the model language to be capable of expressing claims about its own semantic machinery (that is, capable of expressing the designation stuff that we can talk about in the metalanguage). Nothing else will do; in particular, any predicate D' such that the value of D'[A] is .5 when the v(A) = .5 does not express designation; any designation claim must take value .25 or less when v(A) = .5.
Why? Because .5 is not a designated value. Of course, that only means its true-in-real-life that .5 is not designated, which you might want to say does not imply that the value of D[A] should be an undesignated value. Truth-in-real-life (as JC has helpfully stressed to me in conversation) is not supposed to be modelled by designation but by truth-in-the-model (i.e. the behaviour of 'true' in the model).
But I think in order for our D to express designation we need D[A] to be false-in-the-model when v(A) = .5, which (unless I'm missing something) means we want F[D[A]] to be designated when v(A) = .5, i.e. we want T[¬D[A]] to be designated, which can only happen if ¬D[A] is designated, which in turn requires that v(D[A]) be at most .25 (because in this model negation toggles designated values with values of at most .25).
If Beall is saying that no model is capable of expressing these things he seems to be forced to say either that no model is adequate as a model of English, which can talk about its own semantic machinery, or that, like the models, English cannot express claims about its own semantic machinery.
If one says the first thing, then one has to admit that these models can't help us understand the Liar - after all, the Liar arises because English can express claims about its own semantic machinery, and if the models don't model this feature of English, they are irrelevant to the Liar. (This point relates to Beall's claim to have preserved exahustive characterization: the exhaustive characterization we wanted was an exhaustive characterization of all the sentence in the model in terms of their semantic values, but we didn't get that.)
And familiarly, if one says the second thing, one places an implausible limitation on the expressive powers of English.
It seems that the view requires that there is no predicate in the model language like D ('D' for 'designated'), where:
v(D[A]) = 1 or .75 when v(A) = 1 or .75
and v(D[A]) = 0 or .25 when v(A) = 0, .25 or .5
Otherwise the sentence
A*: ¬D[A*]
presents a problem. (It is designated iff it isn't.)
But it seems to me that such a predicate is needed in order for the model language to be capable of expressing claims about its own semantic machinery (that is, capable of expressing the designation stuff that we can talk about in the metalanguage). Nothing else will do; in particular, any predicate D' such that the value of D'[A] is .5 when the v(A) = .5 does not express designation; any designation claim must take value .25 or less when v(A) = .5.
Why? Because .5 is not a designated value. Of course, that only means its true-in-real-life that .5 is not designated, which you might want to say does not imply that the value of D[A] should be an undesignated value. Truth-in-real-life (as JC has helpfully stressed to me in conversation) is not supposed to be modelled by designation but by truth-in-the-model (i.e. the behaviour of 'true' in the model).
But I think in order for our D to express designation we need D[A] to be false-in-the-model when v(A) = .5, which (unless I'm missing something) means we want F[D[A]] to be designated when v(A) = .5, i.e. we want T[¬D[A]] to be designated, which can only happen if ¬D[A] is designated, which in turn requires that v(D[A]) be at most .25 (because in this model negation toggles designated values with values of at most .25).
If Beall is saying that no model is capable of expressing these things he seems to be forced to say either that no model is adequate as a model of English, which can talk about its own semantic machinery, or that, like the models, English cannot express claims about its own semantic machinery.
If one says the first thing, then one has to admit that these models can't help us understand the Liar - after all, the Liar arises because English can express claims about its own semantic machinery, and if the models don't model this feature of English, they are irrelevant to the Liar. (This point relates to Beall's claim to have preserved exahustive characterization: the exhaustive characterization we wanted was an exhaustive characterization of all the sentence in the model in terms of their semantic values, but we didn't get that.)
And familiarly, if one says the second thing, one places an implausible limitation on the expressive powers of English.
Friday, April 14, 2006
UConn
I’ve just got back from the University of Connecticut, where I gave my paper on Modal Knowledge at the Philosophy Department Colloquium and got lots of helpful feedback. The UConn grad students have just started a blog, What Is It Like To Be a Blog?.
I also attended a conference on Conditionals. On Saturday, Dorothy Edgington told us what she thinks about subjunctive conditionals, namely that they do not have truth values but rather express the speaker’s belief that the conditional probability of the consequent on the antecedent is high (i.e., basically, they function pretty much the way she thinks indicatives do, but in a different tense).
I was worried that there seem to be cases where the consequent is unlikely to be true given that the antecedent is, yet still would be true if the antecedent was. The existence of such cases suggests that subjunctives and conditional probabilities are not correlated in the way Edgington claims. We discussed the following example (one suggested by Edgington when I raised my worry in discussion time). Suppose you decide at the last minute not to get on a plane which is very unlikely to crash, and the plane in fact crashes, killing all its passengers. It’s tempting to think that the probability of your dying conditional on having got on the plane is low, because the plane’s chances of crashing were low, yet clearly if you had got on the plane you would have died.
Edgington replied that we simply have to find the right conditional probability, in much the same way that (say) someone who likes closest-world semantics for these conditionals has to find the right similarity relation. In the above case, she said, the right conditional probability is that of your dying given that you got on the plane and it crashed. To save the proposal, you just need to find the right pieces of further information about the world to take into account, besides what is mentioned in the antecedent. This information will makes the conditional probability of the consequent high.
This might be thought to be a bit ad hoc, given that the crashing is not mentioned in the antecedent of the conditional we’re actually interested in. But regardless of that, I think it is a problem that the response won’t always work if there is indeterminacy in the world. For in that case, there will – or at least, could – be some unlikely events that just happen, and are not rendered any more likely however much further information about the world we take into account.
Suppose C is an event that would have happened, without being determined, if A had happened, although it was very unlikely to do so. Then the subjunctive:
If A had happened then C would have happened
looks true, although the conditional probability of C on A is low. And in this case there is no further information about the world that we can take into account which will make the conditional probability of C high – that is, there is nothing which can play the role played by the fact that the plane crashed in Edgington’s response to the first example.
So Edgington’s account of counterfactuals seems at risk of giving the wrong results unless we assume there is no indeterminacy. And this seems to be a distinctive problem for the account, not analogous to an problem faced by closest-world approaches.
I also attended a conference on Conditionals. On Saturday, Dorothy Edgington told us what she thinks about subjunctive conditionals, namely that they do not have truth values but rather express the speaker’s belief that the conditional probability of the consequent on the antecedent is high (i.e., basically, they function pretty much the way she thinks indicatives do, but in a different tense).
I was worried that there seem to be cases where the consequent is unlikely to be true given that the antecedent is, yet still would be true if the antecedent was. The existence of such cases suggests that subjunctives and conditional probabilities are not correlated in the way Edgington claims. We discussed the following example (one suggested by Edgington when I raised my worry in discussion time). Suppose you decide at the last minute not to get on a plane which is very unlikely to crash, and the plane in fact crashes, killing all its passengers. It’s tempting to think that the probability of your dying conditional on having got on the plane is low, because the plane’s chances of crashing were low, yet clearly if you had got on the plane you would have died.
Edgington replied that we simply have to find the right conditional probability, in much the same way that (say) someone who likes closest-world semantics for these conditionals has to find the right similarity relation. In the above case, she said, the right conditional probability is that of your dying given that you got on the plane and it crashed. To save the proposal, you just need to find the right pieces of further information about the world to take into account, besides what is mentioned in the antecedent. This information will makes the conditional probability of the consequent high.
This might be thought to be a bit ad hoc, given that the crashing is not mentioned in the antecedent of the conditional we’re actually interested in. But regardless of that, I think it is a problem that the response won’t always work if there is indeterminacy in the world. For in that case, there will – or at least, could – be some unlikely events that just happen, and are not rendered any more likely however much further information about the world we take into account.
Suppose C is an event that would have happened, without being determined, if A had happened, although it was very unlikely to do so. Then the subjunctive:
If A had happened then C would have happened
looks true, although the conditional probability of C on A is low. And in this case there is no further information about the world that we can take into account which will make the conditional probability of C high – that is, there is nothing which can play the role played by the fact that the plane crashed in Edgington’s response to the first example.
So Edgington’s account of counterfactuals seems at risk of giving the wrong results unless we assume there is no indeterminacy. And this seems to be a distinctive problem for the account, not analogous to an problem faced by closest-world approaches.
Tuesday, April 04, 2006
Time Travel and Backwards Causation
It seems to be quite widely assumed (I am informed, by sources who read more about this sort of thing than I do) that backwards time travel requires backwards causation. It wouldn't suffice for time travel if in 2015 I climbed into a time machine and someone looking and acting exactly like how I look in 2015 came into existence for no apparent reason in 1926. Rather, that person's turning up in 1926 would have to be caused by my actions in 2015.
I agree with the insufficiency claim. But I'm not sure whether the causal requirement is motivated by it. (I'm also hung up on whether it might be a conceptual truth that causation happens forwards, not backwards, but let's not worry about that.) Wouldn't it be enough if there were the right kind of non-casual explanation of this person's turning up in 1926, in terms of my actions in 2015? If not, why not?
(I am concerned that I will be trussed up in a sack and sent back to Cambridge for posting on this, but I'm going to do it anyway ...)
I agree with the insufficiency claim. But I'm not sure whether the causal requirement is motivated by it. (I'm also hung up on whether it might be a conceptual truth that causation happens forwards, not backwards, but let's not worry about that.) Wouldn't it be enough if there were the right kind of non-casual explanation of this person's turning up in 1926, in terms of my actions in 2015? If not, why not?
(I am concerned that I will be trussed up in a sack and sent back to Cambridge for posting on this, but I'm going to do it anyway ...)
Tuesday, March 28, 2006
Basic Knowledge Workshop: Call For Graduate Papers
I'm organizing an Arché workshop on Basic Knowledge, which will take place on 24-25 November 2006. Speakers will include Jason Stanley, Duncan Pritchard, Jessica Brown and Timothy Williamson. There will be a slot for a graduate student paper. Graduate students, and those who obtained their PhDs within the last twelve months, are invited to submit papers of not more than 5000 words. Please send me submissions as email attachments in Word or similar format (no pdf files please). Suitable topics include: Sceptical Paradox, Transmission and/or Closure, Non-Evidential Warrant, Internalism and Externalism, and A Priori Knowledge. Particularly welcome are papers which open up new areas of enquiry within these fields, and/or highlight directions in which further research is needed. Travel and subsistence will be covered by Arche for the author of the selected paper. The deadline for submissions is 31 August 2006.
ADDENDUM: Submissions should be prepared for blind review.
ADDENDUM: Submissions should be prepared for blind review.
Wednesday, March 15, 2006
Counterfactuals and Ontic Vagueness
Following on from the idea I floated in this post, I'm posting a draft of a note on why you shouldn't use counterfactuals to characterize commitment to ontic vagueness (which won't surprise those who know that I tend to think you probably shouldn't use counterfactuals to characterize anything metaphysically interesting ...). Comments very welcome, as always.
Tuesday, March 07, 2006
Saturday, March 04, 2006
Weighing Implausibilities
Here's something I was wondering about during Tim Williamson's talk at the Arché Vagueness Workshop yesterday.
Suppose you want to keep bivalence, and you also think that the only way for something to be an aspect of a predicate's meaning is for our use of the predicate to determine that it is (both Williamsonian thoughts, I gather). But you also think it is at least prima facie implausible that usage determines an exact cut-off point for all the vague predicates (a thought pressed against Williamson by McGee and McLaughlin).
We seem to have at least two options.
1: Accept the implausible-sounding claim (with Williamson), or
2: Argue that many of the things we think are vague predicates ('red', 'bald' etc.) are in fact not predicates at all. By bivalence, in order for them to be predicates we would need there to be cut-off points for their application. But it is implausible that our use of these terms determines such cut-off points. And there is nothing else which can do this sort of meaning-constituting work.
It's initially implausible, sure, that words like 'red', 'bald' and so on are not predicates. But my question is: by what sorts of methodological considerations do we weigh this implausibility against that of the claim that usage determines cut-off points for all such terms?
(Incidentally, Williamson mentioned that he talks about Option 2 in his book on vagueness, which I haven't had a chance to look at yet. He obviously has reasons for preferring Option 1, which I will be interested to read.)
Suppose you want to keep bivalence, and you also think that the only way for something to be an aspect of a predicate's meaning is for our use of the predicate to determine that it is (both Williamsonian thoughts, I gather). But you also think it is at least prima facie implausible that usage determines an exact cut-off point for all the vague predicates (a thought pressed against Williamson by McGee and McLaughlin).
We seem to have at least two options.
1: Accept the implausible-sounding claim (with Williamson), or
2: Argue that many of the things we think are vague predicates ('red', 'bald' etc.) are in fact not predicates at all. By bivalence, in order for them to be predicates we would need there to be cut-off points for their application. But it is implausible that our use of these terms determines such cut-off points. And there is nothing else which can do this sort of meaning-constituting work.
It's initially implausible, sure, that words like 'red', 'bald' and so on are not predicates. But my question is: by what sorts of methodological considerations do we weigh this implausibility against that of the claim that usage determines cut-off points for all such terms?
(Incidentally, Williamson mentioned that he talks about Option 2 in his book on vagueness, which I haven't had a chance to look at yet. He obviously has reasons for preferring Option 1, which I will be interested to read.)
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