Tuesday, 17 March 2015

On Kripke's Intuitive Anti-Quinean Defence of De Re Modality

This is the second post in a series on de re modality and quantification into modal contexts. The first is here.

Immediately after the passage quoted at the beginning of the last post where Kripke introduces the problem of de re modality, he goes on to argue that de re subjunctive modal ascriptions, and the notion of necessary and contingent properties, have intuitive content. I will quote this influential passage in full, and make a criticism of it. I will then suggest a weaker argument from analogy which could be given in its stead, and finally indicate my own view on the matter.

Here is the passage:

It is even suggested in the literature, that though a notion of necessity may have some sort of intuition behind it (we do think some things could have been otherwise; other things we don't think could have been otherwise), this notion [of a distinction between necessary and contingent properties] is just a doctrine made up by some bad philosopher, who (I guess) didn't realize that there are several ways of referring to the same thing. I don't know if some philosophers have not realized this; but at any rate it is very far from being true that this idea [that a property can meaningfully be held to be essential or accidental to an object independently of its description] is a notion which has no intuitive content, which means nothing to the ordinary man. Suppose that someone said, pointing to Nixon, 'That's the guy who might have lost'. Someone else says 'Oh no, if you describe him as "Nixon", then he might have lost; but, of course, describing him as the winner, then it is not true that he might have lost'. Now which one is being the philosopher, here, the unintuitive man? It seems to me obviously to be the second. The second man has a philosophical theory. The first man would say, and with great conviction 'Well, of course, the winner of the election might have been someone else. The actual winner, had the course of the campaign been different, might have been the loser, and someone else the winner; or there might have been no election at all. So such terms as "the winner" and "the loser" don't designate the same objects in all possible worlds. On the other hand, the term "Nixon" is just a name of this man.' [Presumably the quote from the imagined "first" man should have ended one sentence ago, but this is how it is in the text. -TH] When you ask whether it is necessary or contingent that Nixon won the election, you are asking the intuitive question whether in some counterfactual situation, this man would in fact have lost the election. If someone thinks that the notion of a necessary or contingent property (forget whether there are any nontrivial necessary properties [and consider] just the meaningfulness of the notion) is a philosopher's notion with no intuitive content, he is wrong.

I do not want to be dogmatic about this, but I suspect that there may be a bit of a bait-and-switch going on here. Certainly, it seems everyday and intuitive for someone to point at Nixon and say 'That's the guy who might have lost'. But then what this 'first man' says in response to the 'unintuitive man' (the philosopher), is beginning to sound pretty philosophical itself, albeit sounder. It is true that what he says, especially if you're trained in philosophy, seems intuitively compelling. But I think it's quite arguably out of character for the first man.

One way of making good on this suspicion is to reflect that forms like 'could have' and 'might have' do not just signal talk about counterfactual scenarios and counterfactual possibility. They also commonly find a retrospective epistemic modal use. And it seems to me that this is the most natural way to interpret the everyday, non-philosophical remark of the 'first man' above, 'That's the guy who might have lost'. To say that Nixon might have lost, on this suggestion, means something like: at some former stage, things could have gone either way – it would have been unreasonable then to be convinced that he would win.

This seems to me like a fairly everyday thing to say. The meaning Kripke intends – where what is asserted means something like (ignoring the later Finean distinction between essential and necessary properties): its not part of Nixon's essence that he won the election – seems less so.

We can also argue along Gricean lines that the first interpretation yields something which it might actually be good to say in the sort of conversation about contemporary events Kripke has in mind. But saying this thing about – speaking loosely – Nixon's essence seems pragmatically odd; if you know that, then presumably you know something stronger from which it follows (such as that winning some election can't be an essential property of anyone), rather than making it sound as if there's something special about Nixon here. (Consider an obscure bystander around Nixon's age: it seems, from an unabashedly philosophical point of view now, implausible that it is part of this bystander's essence that he didn't go into politics, get to run for Presidential office in the election in question, and lose. So it seems you could say of that guy too that he might have lost the election, in the sense in which Kripke has in mind.)

So, I find Kripke's story about the first man and the unintuitive, philosophical man unconvincing: if the first man were really not a philosopher, I'm inclined to think that his intuitive-sounding utterance of 'That's the guy who might have lost' is far more plausibly interpreted along epistemic lines. This is somewhat ironic, given Kripke's seminal insistence on carefully distinguishing epistemic modality and a priority on the one hand from subjunctive modality on the other.

We can get a better idea of how it might have happened by recalling the grammatical devices Kripke uses to isolate subjunctive modality: what could be the case for all we know a priori is to be distinguished from what could have been the case (given various things we know, and not always a priori). This may lead to an overconfidence in the subjunctive mood (or whatever you want to call it) as a signal of subjunctive modality proper, a signal of the thing Kripke isolated.

Still, this criticism doesn't imply that there is nothing in what Kripke says in this influential passage. Two things can be gleaned from the passage which do militate in favour of his main conclusion, which is that the notion of necessary and contingent properties makes sense.

One is a kind of argument from analogy: even when you interpret the first man's initial, everyday-sounding utterance along more appropriate, epistemic lines, it is clear that what is under discussion is not a statement: that is, de re epistemic modality makes sense. (For a recent study of that topic cf. Seth Yalcin's work.) And so, putting this consideration together with Kripke's compelling isolation of a concept of necessity applying to propositions which is distinct (intensionally and extensionally) from those of a priority and analyticity, we might naturally expect de re modal constructions where the modality is of this broad sort, having to do with alternative ways the world could have been in some non-epistemic sense, to be possible too.

Another is a direct philosophical appeal to our intelligence: forget guys on the street, forget questions about what they may or may not say without thereby becoming philosophers, and just think about it. What the first man is made to say in response to the unintuitive man, even though it just sounds like Kripke doing philosophy, seems awfully compelling. To quote it again: 'the actual winner, had the course of the campaign been different, might have been the loser, and someone else the winner; or there might have been no election at all. So such terms as "the winner" and "the loser" don't designate the same objects in all possible worlds'.

The situation, as I see it, is something like this: Kripke has clarified and isolated notions of necessity, contingency etc., which in the first instance apply to propositions and perhaps states of affairs. Now, by analogy with other expressions in our language, we are led to consider forms like 'is necessarily F' and 'There is an which is necessarily F' (or 'There is an x such that it is necessary that x is F'), where we have a vague idea that the terms 'necessarily' and 'necessary' here are, in some way, to express this same notion, which we know in the first instance in application to specific propositions. Consider the syntax of quantified modal logic, where modal operators are combined with first-order logic, in advance of any definite understanding of what these formulas are to mean.

Philosophers often behave like little children who scribble some marks on a piece of paper at random and then ask the grown-up "What's that?" — It happened like this: the grown-up had drawn pictures for the child several times and said "this is a man," "this is a house," etc. And then the child makes some marks too and asks: what's this then? C&V 17e

Our problem is, in a way, similar to that of making a game which is like an existing game, but different in some respects – but where the required similarities and differences are not completely spelt out (and how could they be, without thereby completing the task already?). For example, chess for three players, or with no queens.

In the present case, the task draws us in, since we feel we can already make some dim sense of these constructions. The question of whether this can be spelt out clearly, and the spelling out of it should this be possible, is of logico-philosophical interest. Furthermore, the issue is connected in many people's minds with difficult philosophical topics – with Aristotelian essentialism, with metaphysics, and with confused issues to do with whether modality is 'located' or 'grounded' in language and thought, or in other things.

Accordingly, in the next post in this series I will take up the challenge of de re modality, trying to adapt my account of necessity as an attribute of propositions so that it can be applied to de re modality. My main assumption in taking up this challenge is: there must be a connection here, and a tight one (e.g. not something you would have to describe using worlds like 'sometimes' or 'usually'), and we now have to make this clear. This will also take heat off the idea that de re modality makes no sense, but perhaps in a way which might look strange from the point of view of certain ways of thinking about analysis: the right hand sides of my analyses will in many ways be less simple, more problematic and more difficult than the left hand sides, the things to be analysed. But the problems are not the same ones as affect the left hand sides, and that is important. Roughly, I want to show that de re modal talk is not left hanging by itself, when we have a notion of necessity which applies to propositions. It may in a sense be more intelligible left as it is than when analysed along the lines I propose. But we must distinguish between the first-order intelligibility of a linguistic form on the one hand, and our philosophical conception of how that form works and what it does on the other. Connecting de re modal talk to de dicto can, I think, help a lot with the latter.

(Contrast, for example, Kit Fine's approach of taking essence as something basic – I get the sense of a wall having been erected to keep out trouble, but which also leaves us hapless and isolated. It is similar with his metametaphysical ideas: we must distinguish how things really or metaphysically are from how they are simpliciter, or something like that – and if you don't understand that, too bad: we're up against a wall. The difference, I think, is that in the first case the talk (essence talk) does make some sense, but has been walled off from things which may shed light on it in a way that can make this hard to believe, and hard to grasp, whereas in the second case, you have at most a degenerate, affect-charged sense, and the walls are merely there in a vain attempt to stop this from becoming glaringly apparent.)

Sunday, 15 February 2015

De Re Modality and Quantifying In

This is the first in a series of posts about these issues, the plan for which is given below.

My account of subjunctive necessity treats subjunctive necessity, in the first instance, as an attribute of propositions. That is, it is in the first instance an account of de dicto subjunctive necessity, in the sense that it applies to attributions of necessity and other definable modal properties to propositions (dicta).

As it stands, this account does not apply to propositions which say, of some object, that it necessarily has some property. For example, 'John is necessarily not a number'. That is, the account does not deal with de re subjunctive necessity (assuming such a thing is to be recognized at all).

Now, 'John is necessarily not a number' may look like just another way of saying '“John is not a number” is necessary'. Of course, nothing is stopping us stipulating that it is to be read that way. But furthermore, it might seem to already, naturally, say something equivalent to that. Or it might not. This issue will be seen below to turn on the issue of whether extensionally identical atomic propositions can differ in counterfactual invariance, and in turn modal, status – or more strictly speaking, it will be seen to turn on that given a certain natural approach to the interpretation of de re modal ascriptions.

Unlike '”John is not a number” is necessary', which refers to a proposition and predicates necessity of it, 'John is necessarily not a number' refers to John, and seems to be open to quantification in a way that the de dicto attribution is not: we can seemingly infer from it that something is necessarily not a number, whereas existential generalization on the de dicto attribution yields only 'Something is necessary'. This suggests that de re modal attributions like 'John is necessarily not a number', at least on one natural reading, do not have corresponding de dicto attributions which say exactly the same thing (even if they are equivalent in some sense). It also raises the issue of the interpretation of quantification into modal contexts.

I will begin in this post with some further consideration of what the problems of de re modality and quantifying in amount to. 

In the next post in the series, I will discuss Kripke's criticism in Naming and Necessity of Quine's attempts to make genuine de re modal attributions look bizarre or unintelligible, including the discussion of Nixon, where Kripke argues that de re modal attributions make good intuitive sense.

In the next post after that, I will go in search of an account of de re modal attribution given in terms of de dicto modality, eventually lighting on one, but leaving certain complications undiscussed for the time being.

In the next post after that, I will address the problem of quantification into modal contexts by giving an interpretation of the formulae of quantified modal logic (in the form of a method of translation into natural language).

The Nature of the Problem of De Re Modality

Here is Kripke introducing the problem of de re modality in Naming and Necessity (first lecture):
There is one more question I want to go into in a preliminary way. Some philosophers have distinguished between essentialism, the belief in modality de re, and a mere advocacy of necessity, the belief in modality de dicto. Now, some people say: Let's give you the concept of necessity. A much worse thing, something creating great additional problems, is whether we can say of any particular that it has necessary or contingent properties, even make the distinction between necessary and contingent properties. Look, it's only a statement or a state of affairs that can be either necessary or contingent! Whether a particular necessarily or contingently has a certain property depends on the way it's described. This is perhaps closely related to the view that the way we refer to particular things is by a description.

It is important to separate three parts of what Kripke says 'some people say' here:
  1. Given an understanding of de dicto necessity, the issue of de re modal attribution remains, and creates additional problems.
  2. It's only a statement or state of affairs that can be necessary or contingent.
  3. Whether a particular necessarily or contingently has a certain property depends on the way it is described.
I fully endorse (1), as the existence of this section would suggest. But that does not mean I endorse (2) or (3), both of which are curious and not altogether clear. I do not want to be overly pedantic about something which was said, in a fairly preliminary way, in a lecture delivered without notes, but separating these things and considering what (2) and (3) might mean will help us get clearer about the issue of de re modality. It will also help when we consider, in the next post, Kripke's intuitive defence of de re modality (which he gives right after the above quoted passage).

(2) needs finessing if it is not to be a trivial point of language. Someone – say, an Aristotelian essentialist, or Kit Fine – can hold that de re modal attribution makes perfect sense, and fully reject any (3)-like suggestions that the truth of these attributions is somehow description-dependent, and still agree with (2) as stated. They are not saying that an object (one which isn't a statement) can 'be necessary or contingent', but that it can have properties and stand in relations necessarily or contingently.

The real suggestion behind (2), I suggest, is that the notions of necessity and contingency – the notions of subjunctive or metaphysical modality clearly isolated by Kripke – only apply to statements (propositions) or states of affairs. And 'apply' here is understood in such a way that these notions are not automatically precluded from appearing in some other way than in predications of the form 'x is necessary', for example adverbially ('x is necessarily F').

(2), so understood, is not something I want to endorse. While I accept that de re modal attribution poses difficulties over and above de dicto, I think it may be possible to meet these difficulties. However, the meeting of these difficulties will be attempted here by accounting for de re modal attributions (and quantification into modal contexts) in terms of de dicto attributions. (But that doesn't mean there is no other way – I am giving an account, not the account.)

There is something potentially misleading about this talk of difficulties which may perhaps be met (rather than just cleared away, for instance) – as though there is some reason for us to hope that they may be. But that is not how I see the matter. This has to do with my doubts about whether there is any pre-existing intuitive understanding of de re modal attribution and quantifying-in, which I will elaborate in the next post.

So much for (2). What about (3): 'Whether a particular necessarily or contingently has a certain property depends on the way it's described'? This is very curious in a way. Far from being part and parcel of some attitude one might have on these questions consonant with (1) and (2), (3) seems incompatible with what we understood (2) to be getting at; if the relevant modal notions only apply to propositions or states of affairs, then, it would seem, we cannot speak of particulars necessarily or contingently having a certain property, and so we cannot say that their doing so depends on anything.

There is perhaps a way of interpreting what some skeptic about de re modality might mean by this, but there are also good reasons for them not to say it (not least of all that it is highly ambiguous and confusing).

There suggests that there is a danger that (3) is playing a straw man role, or a more subtle bait-and-switch role, in Kripke's influential arguments for the intuitive intelligibility of de re subjunctive modal attributions: trading on a charitable interpretation to make it a plausible attribution to philosophers (the bait), and then switching to an interpretation on which it couldn't possibly be right or even coherent (the straw man).

In light of this, I will now go into (3) at some length. I will do my best to make it easy to keep track of the argument, and its place in the bigger picture.

Something someone could say while maintaining (2) (as we have understood it) is this: the only clear, philosophically hygienic thing it could mean to say 'Nine is necessarily odd' is '”Nine is odd” is necessary', and all it could mean to say that 'The number of planets is necessarily odd' is '”The number of planets is odd” is necessary'. (Note however that I will not be advancing this view.)

Now, such a person would then face the issue: where does that leave the question of whether the referent of 'nine' and 'the number of planets', that particular number, possesses the property of oddness necessarily or contingently? What, if anything, does that mean?

It seems to me that the most consistent course for this person would be to say: this question just amounts to whether the proposition:

'The referent of “nine” and “the number of planets”, that particular number, possesses the property of oddness'

is necessary or contingent. Either that, or it has no clear meaning.

But Kripke has this person say that this question somehow depends on how we describe that particular number. But note carefully that this question, interpreted in the way I suggested was most consistent for the hypothetical person we are imagining, concerns a particular proposition. If someone asks something, and what their question really asks is whether some particular proposition is necessary or contingent, you can't respond by saying 'Well, that depends on how you describe …'. The describing has already taken place, in the proposition in question, and it is now time to proceed to actually answering the question.

Another thing this person could say which is similar to (3), but clearer, is this: that the truth of propositions which, superficially, designate an object somehow and say that it has some property necessarily or contingently, depends on how that object gets designated. But in this case, if we say that, surely we should say that these propositions have a misleading form. We should not go along with this form and say, as a kind of explanation of it, that whether some object has a property necessarily or contingently depends on how it is described. (The most deserving meaning for this expression here may still not be deserving enough.)

This can perhaps be seen better by comparing our case with one in which we might genuinely say something like this – i.e. that whether an object is some way or other depends on how you describe it. Consider these propositions: 'The number of planets is, in the subject-term of this proposition, being described as the number of planets', 'Nine is, in the subject-term of this proposition, being described as the number of planets'. The truth of these propositions patently does depend on how the referent of the subject-term is described (or, we might say more neutrally, designated). And we can say that whether that referent, that particular number, has the property of being described in some given proposition as the number of planets depends on how it is described by that proposition. Indeed this seems like a tautology. Or consider an object which naturally, whenever it is described as red, turns red if it is not already red (i.e., irrespective of whether the description was true, it becomes true), but turns another colour if it is described as non-red. Of such an object, we could say: whether it is red or not depends on how it is described.

The modal case is plainly not like this at all. Saying that whether a particular has a property necessarily or contingently depends on how it is described is, at best, a clumsy way of saying that the truth of (what superficially look like) de re modal attributions depends on how the object in question is designated. At worst, it is a tortuously confused piece of nonsense.

Another, perhaps more Quinean, thing someone might say which is along the lines of (3) is: de re modal discourse is confused, incoherent – in part because the truth of its claims of necessary or contingent property possession for an object would have to depend on how that object is described. This isn't really clearer than saying that the truth of such claims actually does depend on how the object is described, but the unclarity is less objectionable, since it is being asserted that de re modal discourse is incoherent, and so the thing about description-dependence can be regarded as an incoherent, absurd consequence – where the whole point of bringing it in is to argue that we are not able to make real sense of it.

So, (3) itself seems in danger of being a bit of a straw man for Kripke – it has little to recommend it, and doesn't obviously belong to anyone.

So, we have separated and examined three things involved in the position of the skeptic of de re modality as characterized by Kripke. The first, that given an understanding of de dicto necessity, the issue of de re modal attribution remains, and creates additional problems, is important and endorsed by me. The second, the idea that it is only a statement of a state of affairs that can be necessary or contingent, is something which I hope to undermine in subsequent posts. The third, the idea that whether something has a property necessarily or contingently depends on how you describe it, I have tentatively suggested to be a straw man.

Stay tuned for the next post, on Kripke's intuitive anti-Quinean defence of de re modality.

Tuesday, 20 January 2015

On 'If you're a brain in a vat then you don't have hands'

Much ink has been spilled on skeptical arguments like the following:
  1. If you're a brain in a vat then you don't have hands
  2. You don't know that you're not a brain in a vat
  3. Therefore you don't know that you have hands
There are many variations on this sort of argument, and many issues have been raised about it, for example the issues of the closure of knowledge under implication, and the closure of knowledge under known implication.

I have long felt that there is something very dubious about the first premise in the above formulation (and the analogous premises in the variations). I suspect that coming to terms with this would involve throwing a spanner in the works of some of our ways of thinking about how language functions (we being analytic philosophers, broadly speaking). Not necessarily at the level of explicit commitments, either. And perhaps that is part of the reason why this premise has not been questioned, in anything like the way I want to question it, much in the literature1; it seems very difficult.

In this essay I want to begin to explore this issue. It is a pretty large and confusing issue, and this is only meant to be a beginning, so I will try to be fairly non-technical and to avoid bringing in any very particular overarching theoretical framework, out of fear that if I did so the issue or important aspects of it would get lost.

I will suggest that (1) is not true – or at least, that it isn't true on its most natural readings. If I am right, then we may have a way of avoiding the repugnant conclusions of skeptical arguments like the above, without having to show that we do somehow know that we are not brains in vats. This seems attractive to me – it does intuitively seem to me that I do know that I have hands and that I do not know that I'm not a BIV. Or perhaps better, and from a broadly Lewisian contextualist perspective on knowledge-ascriptions (a perspective I find independently attractive)2, it seems to me that there are levels of strictness – or sets of relevant alternatives – on which 'I know I have hands' comes out true while 'I know I'm not a BIV' comes out false.

So, one thing which may come out of this discussion is a way of diffusing a large class of skeptical arguments. But my motivation isn't primarily epistemological – isn't to vouchsafe certain bits of presumed knowledge. For my part, I don't think that sort of philosophical anxiety about whether we really know such-and-such should always be indulged and attempts made to alleviate it by the straightforward course of trying to come up with reasons to be reassured. It seems largely pathological to me – something which ought to be scrutinized and dissolved, as I think Wittgenstein tried to do.3

No, I'm more interested in (1) for its own sake, and for the sake of the issues which come up once we begin to question it. As we will see, these are fundamental issues in the philosophy of language – for example, the issue of what propositions are, and the issue of whether we ought to think of propositions as sorting all possibilities into two categories (one of which may be empty): those in which the proposition holds, and those in which it does not. (We will not have space to go deeply into these issues in a general way, but we will end up seeing that we have here found one good path into them.)

So much for scene-setting. To kick off the investigation, let us note that (1) is generally supposed to be accepted readily, as though it were obvious. It just appears in skeptical arguments as a premise, which we're meant (by the skeptic) to accept without argument. Once you start scrutinizing it as I have done, this quickly begins to seem very odd and confusing. So, to try to avoid being hampered by such confusion when we do scrutinize it, let us first ask the question: why might (1) seem true?

Silly as it sounds – silly as it is – the answer appears to be something like: when (1) strikes us as true, we are as it were picturing a brain sitting in a vat, and observing that there are no hands in that picture. Or we are picturing a brain sitting in a vat, and a mad scientist tending it, and noticing a striking contrast between the two figures – the scientist-figure has a body and hands, whereas the other figure is just an organ (in a vat). Something along those lines.

And here is a good place to consider and put aside one particular line of attack on (1). It is a comically literal-minded objection. I did not think of it myself, but found it when I was searching the literature for previous attempts at calling propositions like (1) into question. (And this is all I found.) Roush (2010) argues that it is not true that if you're a brain in a vat then you don't have hands, on the grounds that you might be a brain in a vat with hands just stuck on (!) – that is, where there are attached hands in the environment which contains the brain and the vat, not the environment simulated for the brain. Maybe the hands are just stuck on with glue and dangle there, or maybe they are delicately connected up neurologically with the brain, making for a queer straddling of two “worlds” (or environments, or levels of reality) on the part of the BIV.

There is something very frustrating about this objection. It is frustrating, I think, because if you just accepted this objection, deciding on its basis that (1) is false, and then walked away, you would have bypassed all the deep issues in the philosophy of language which we can dig up by scrutinizing (1), thus losing a valuable opportunity.

Calling the objection into question – scrutinizing it – may lead somewhere, however. For instance, we may ask whether a BIV with the envisaged appendages really counts as 'having hands', or whether this is really the best candidate meaning for 'having hands' in connection with a BIV. And here we begin to get the sense of an abyss, this sense of unforeseen ambiguity or indeterminacy, and the sense that this sort of thing, since it's not very clear how we should think about it, has ominous implications for how we think philosophically about language.

These spectres raised just now are at the heart of what I am concerned with here, but they come up with (1) itself anyway, quite apart from the literal-minded objection we have just looked at. So, what I propose is that we put this objection to one side, go back to what we said about why (1) might seem plausible, and proceed from there.

(If you think the objection does show (1) to be simply false, you may be more comfortable with the ensuing discussion if you exchange (1) for something like 'If you're a brain in a vat without appendages as envisaged in Roush (2010), then you don't have hands'. But really, it hardly matters, since the point of this discussion is not really to determine the truth-value of (1). Indeed, the idea that (1) as used in skeptical arguments has a definite meaning, and a definite truth-value, may not survive scrutiny. And our idea of what a 'definite meaning' is, and of what role the notion of definiteness should play in thinking about meaning, may have to be altered too.)

So, we picture a BIV and there are no hands in the picture. And we picture a scientist tending the BIV and see a contrast between the figure of the scientist and the BIV-figure. And with this in mind, we might be tempted to say 'The BIV doesn't have hands and the scientist does'.

But consider a different situation, in which we have two BIVs. It doesn't matter whether or not they are plugged into the same simulation. What does matter is that, in their lives in their simulation(s), one of them is an anatomically normal human, while the other has been in an accident and lost their hands. Mightn't we, if this was the first case we had considered, be tempted to say 'One BIV has hands, the other does not'? And if we would be right in so saying, then we would be wrong to say (without shifting the meanings of relevant terms) that if you're a brain in a vat you don't have hands; the first BIV would then be a counterexample to (1).

Here it might be objected that it would not be correct to say, unqualifiedly, 'One BIV has hands, the other does not' – rather, one would, to be both right and completely explicit, have to say something like 'One BIV has hands in its simulated environment, the other does not'.

Suppose we go along with the objection. We can still ask about things the BIVs may say, in their simulations. And we could reason as follows: Surely, if the first BIV says, in the simulation, 'I have hands', they are, in the simulation, saying something true. And surely if they say, in the simulation, 'I am a BIV', they are, in the simulation, saying something true (even if they could never know it to be true). And thus, if they said 'If you're a brain in a vat then you don't have hands', they would be saying something false – something to which their very case is a counterexample. And if that's right, how could (1) fail to be false? How could our situation differ from the BIV in question's situation in such a way that (1) is true, whereas their utterance – in the simulation – of 'If you're a brain in a vat then you don't have hands' – is not? I can see no way. And furthermore, if there was a way, surely it would turn on us not being BIVs, not living in a simulation – and in that case, we wouldn't be able to know (1) without first knowing that we are not BIVs, and so the skeptical argument could no longer be run.

Now, the above reasoning seems natural, but of course it could be challenged. The most salient way it could be challenged would be to follow Putnam's notorious paper (1981) in saying that, when the BIV says, in their simulation, 'I am a BIV', they are saying, in their simulation, something false, contra the above reasoning.

I do not have space here to lay out Putnam's arguments in full, and to discredit them in detail, but I think it is important to realize that Putnam is completely wrong on this point, and to see why. I will now briefly try to defend this, and to say something about what was going on with Putnam for him to be led so far astray.

Putnam begins with a causal theory of reference, according to which what you're talking about when you say something is what stands in an appropriate causal relation with your utterance. He argues, from the causal theory, that since a BIV could have no causal contact with the brain they are, and the vat they are in, they could not be talking about that when they say 'I am a brain in a vat' – rather, their utterance is, according to Putnam, about 'vats-in-the-image', 'or something related (electronic impulses or program features)'. And since they, the utterers, are not vats-in-the-image, i.e. not vats belonging to their simulation, nor the relevant 'related' things, what they thus say comes out false.

There are lots of things about this we could argue with – the idea that the BIV's talk might literally refer to electronic impulses or program features seems to me very crude and objectionable, for instance – but I will confine myself to three points, the first two of which are closely related to each other.

Firstly, note that singular reference – reference to particular objects – isn't what is in question here. Putnam isn't saying that to say something which is made true by the state of some particular object O requires that we have causal connections to O itself. That, after all, would yield absurd consequences (not that that tends to stop Putnam, but ignore that; these absurd consequences aren't as cool or interesting). For example, I may say, let us suppose on a whim, 'A man will walk into the room now', and if a man immediately walks in, what I said is true, in virtue of that particular man's walking in. But of course the man need not have any causal connection with what I said. All Putnam would insist on is that, in order to be about men at all, my talk needed to have an appropriate causal connection with some man or men. Likewise, in order for a BIV to think or say they are a BIV, their thought or talk doesn't have to be causally connected with the brain they are or the vat they are in. It just has to be connected with some brain(s) and vat(s).

Secondly, why can't there be a general category marked with the word 'vat' which includes as members both “vats-in-the-image” - vats in simulations – and vats outside simulations? (Likewise for 'brain'.) I think there can. Consider things like happiness and intelligence: a BIV with a rich life is surely acquainted with these things, and causally connected with exemplars of them – and so they can have a category, for example marked 'expressions of happiness', and this category would include both things in their simulated environment and any appropriate things outside the simulation. And so Putnam's argument falls down here, by implicitly holding that the relevant reference classes – the 'brain' class and the 'vat' class – can only include things in the utterer's “world”. Once we see this is not so, we can go along with Putnam's basic causal-theoretic starting point, but maintain that there is nothing stopping them thinking they are BIVs, because they can form categories – by means of causal connections to brains and vats in their environment – which manage to include the brain they are and the vat they are in, despite those particular instances not being in their environment.

Thirdly, and stepping back a bit, note how implausible and crude Putnam's interpretation of the BIV's utterance 'I am a BIV' is; it's supposed by Putnam to assert something which to the BIV would be obviously wrong – namely, that they are brains in their environment in vats in their environment. And yet a reflective BIV might not find their utterance of it obviously wrong at all. This suggests that something has gone badly wrong. At a very general level, we may say that Putnam's problem is that he has inappropriately treated the language-game of talking about being a BIV as being just like an ordinary one about things in our environment. But it is plainly not that. Language, we might say, is here playing an entirely new trick. We may not be able to come up with a theoretical understanding of it which would satisfy Putnam, but that does not mean he gets to falsify it.

So, if I'm right about Putnam here, then the reasoning we went through just before considering him seems hard to argue with. And thus, it seems that (1) isn't true, at least on the most natural ways of understanding it. At the very least, it should certainly seem by now that (1) is not the straightforward truth it may have looked to be at first. There are serious challenges to be raised against the naïve, unreflective procedure of just (doing something like) picturing a brain in a vat, observing that there are no hands in the picture, and drawing (1) as a conclusion.

But we are in a bit of a muddle now, only halfway through the essay. A lot of arguments and worries have piled up. I want now to try to restore our energies by clearing the table and approaching the issue from the other side: why might we think (1) is false?

I have an intuitive case to make for thinking that (1) is false. It involves considering statements made in ordinary, everyday conversation, statements which intuitively seem to imply that the utterer has hands, but which intuitively seem not to imply that the utterer is not living in a simulation. For example, suppose someone asks me to help them with something and I say 'OK, one second - I'm just washing my hands'.

This statement – that I'm washing my hands – surely implies that I have hands. Furthermore, I find it very intuitive that it does not imply that I'm not living in a simulation, or that I'm not a BIV; that simply isn't at issue at all. It is completely independent of the truth of what I said.

Having hands is compatible with it not being the case that I'm not a BIV. And so, having hands is compatible with my being a BIV. And so it can't be true that if you're a BIV then you don't have hands.

The key intuition there – that my ordinary statement does not imply that I'm not living in a simulation – can perhaps be bolstered by thinking a bit about the space of scenarios in which I am living in a simulation, and seeing that it is possible to take an attitude to many of these scenarios which is quite unlike regarding them as epistemic nightmares, i.e. situations in which we're in really bad shape epistemically – where much of what we ordinarily think we know fails to even be true.

Certainly we can imagine simulation-scenarios which are epistemic nightmares. We may be BIVs whose tending scientists are engaging in all kinds of foul play, planting false memories and moving things around on us. Also diabolical would be if some or all of the apparent agents we are interacting with are not sentient, or not as fully sentient as we think. I don't so much mean that they may not be constituted the way we are, or the way we think they are – after all, multiple realizability might be the case – but rather that maybe all there is to these agents is what's required to generate our interactions with them. And in lots of cases, corners may be cut, so to speak – when we think they're off by themselves having a rich mental life, perhaps often nothing of the sort is true. But nightmarish scenarios like this are clearly a special subset of all simulation scenarios; in many of the latter, we may not be wrong about much of anything. It just might be the case that, unbeknownst to us, there is a higher level of reality “hosting” the one we inhabit, and this level may involve brains in vats.

From this point of view, we can see that there is no need to respond to the news that you're a brain in a vat by revising your belief that you have hands. Why not treat the news instead as telling you, among other things, something new about your hands (and everything else in your environment), namely that they are “hosted” at a higher level of reality, or speaking crudely, are constituted by electrical impulses or program features. (I say 'crudely' because the relation is obviously not the normal one of constitution from normal physical inquiry. Physics can be done in a simulation, too, and facts about the simulation being a simulation need not be regarded as belonging to it.)

I contend, then, that once we reflect a bit, we can see that (1) is false, at least on the most natural ways of construing it.

Why the hedge about 'most natural ways'? Well, there is one way of construing 'hands' I can think of which is not totally discontinuous with what 'hands' really means and which would make (1) come out true. Namely, a way on which hands are taken as a matter of definition to be things which exist only at the highest level of reality. (Note, in case it seems woolly or unclear, that this notion of levels of reality I've been throwing around does not precede, or exist apart from, considerations of simulations. It is a special notion for talking about these very special matters. Despite possible appearances, there's no more general story about it which could be missing or unsatisfactorily hand-waved to here.)

So there is this construal. But when we adopt it, the conclusion of the skeptical argument, that we don't know that we have hands, isn't particularly repugnant any more. And this, by the way, shows that the construal in question isn't very natural, since we do feel the conclusion as ordinarily understood to be highly repugnant. That conclusion can't be put at the end of the skeptical argument without either rendering (1) false, or keeping it true but equivocating on 'hands'.

So much for (1) and its role in the skeptical argument. I will now begin to conclude, with some more general remarks about meaning and propositions.

It seems like there's something artificial about pinning a particular resolution of these issues of 'What exactly does it take to be a hand, anyway?' on ordinary talk about hands, no matter which one we pick. Rather, something along the lines of there being no fact of the matter seems to be the case. Consider in this connection Wittgenstein's case of the disappearing chair:

§80. I say "There is a chair". What if I go up to it, meaning to fetch it, and it suddenly disappears from sight?—"So it wasn't a chair, but some kind of illusion".—But in a few moments we see it again and are able to touch it and so on.—"So the chair was there after all and its disappearance was some kind of illusion".—But suppose that after a time it disappears again—or seems to disappear. What are we to say now? Have you rules ready for such cases—rules saying whether one may use the word "chair" to include this kind of thing? But do we miss them when we use the word "chair"; and are we to say that we do not really attach any meaning to this word, because we are not equipped with rules for every possible application of it?

So, what of propositions? What of meaning? Should we say that hand-talk is somehow incomplete, failing to express determinate propositions? Well, we could say that, but this is taking the notions of a proposition and of meaning pretty far from home. And what for? Perhaps the only answer is: to preserve certain ways of thinking about how propositions work, and what they do (for example, the idea we mentioned at the outset that propositions sort all possibilities into two categories). But is that wise? Were these ways of thinking the results of investigation, or a priori requirements? (Cf. entry 107 of the Investigations.)

In any case, does the breakdown of these ways of thinking here mean they have to be chucked out entirely? No – we could think of them as offering an idealized perspective. A perspective which is robust in some areas of thinking, useless perhaps in others, and worse than useless in others again.

Now to stop and take stock. Firstly, (1) is no straightforward truth. Secondly, there's a lot more to it than there might seem to be at first glance. Thirdly, it is very arguably false on the most natural ways of understanding it. There's one somewhat natural way on which it's true, but on that one the conclusion isn't very repugnant. Finally, we have looked fleetingly at what all this might mean for the fundamentals of philosophy of language, and suggested that certain ways of thinking about language which run into trouble here are either just bad, or at best are idealizations which have some value but can easily break down and become inappropriate. And they do break down and become inappropriate very quickly once we scrutinize (1).

References

Lewis, D.K. (1996). Elusive knowledge. Australasian Journal of Philosophy 74 (4):549 – 567.

Putnam, H. (1981). 'Brains in a Vat', Chapter 1 of Reason, Truth, and History. Cambridge University Press.

Roush, S. (2010). Closure On Skepticism. Journal of Philosophy 107 (5):243-256.

Wittgenstein, L. (1953/2003). Philosophical Investigations: The German Text, with a Revised English Translation. Blackwell.

1. I say 'much in the literature' in case there are documents I am unaware of which question it in something like the way I have in mind; I haven't been able to find any. On the other hand, this does seem to me to be the sort of thing that a philosopher might register in passing in a document mainly about something else. I wouldn't be at all surprised therefore to find myself anticipated to some extent in that way.

2. Cf. Lewis (1996).

3. I am uneasy about this though, since running with such epistemological worries and trying to meet them straightforwardly and on their own ground has borne spectacular philosophical fruit, as it were along the way, even if the worries are ultimately never thus met. Russell's quest for certainty and his work, in service of this quest, in mathematical logic and philosophy of language, seems a spectacular example. The quest seems a sad vestige of a screwed up childhood, while the result of the quest includes spectacular advances in logic, the theory of descriptions, and long-overdue attention to Frege. This kind of alchemy seems unsettlingly rife in philosophy – at least, it's a bit unsettling if you hope to do fundamental work in the subject yourself. Another example would be Nietzsche's writing Zarathustra in the wake of his humiliating falling out with Paul Rée and Lou Salomé.

Saturday, 10 January 2015

Is Propositional Tautologousness a Modal Notion? (Raisins at Dawn #3)

After writing what appears below, I found a treatment-in-passing of the very same issue by von Wright in a rich paper called 'Modal Logic and the Tractatus'.

Discuss: is PC-tautologousness a modal notion?

'Can't come out F'.

But, having a populated abstract space of valuations:

'Doesn't come out F in any row/valuation'.

But then what goes into the conception of 'all valuations'? Isn't this the same as, or tantamount to, 'all possible valuations'?

But what if one tries to gainsay that?

'No, they're all actual.' - One can give non-modal conditions for 'permissible valuation', to be sure. Picking them out of a larger space. But how do we get the notion of the larger space?

We can say: there are valuations. A valuation is a mapping from atoms to {0, 1}. Any mapping from atoms to {0, 1} is a valuation.

We get, as it were, modal effects from a population of abstracta. And it seems we can conceive these abstracta without modal notions. That is, 'mapping from "p" to {0, 1}' doesn't seem like a modal notion.

But what about 'all such mappings'? Is there even any basis for decision? Is there a determinate answer? (Open texture.) Or is there a need to further fix concepts here? More than one legitimate way of going?

If so, we could have something like 'weakly modal' vs. 'strongly modal' so that 'all such mappings' is weakly but not strongly modal. But how do we draw the line?

For can't we, at least superficially, pull the same trick out in all cases, or a great many more than I was dimly thinking of above? The trick, that is, of trading modality - or strong modality - in for abstracta? Isn't ersatzism just such a move? Can we find a principled way of refuting ersatzism but allowing the move in the PC case?

I'm dimly seeing two distinctions:

One:

The case where everything under discussion is abstract, part of the abstract population.

vs.

The case where, as it were 'concrete configurations' are under discussion. So that to be a possible concrete configuration is to correspond to one of the abstract population. E.g. a switchboard.

Another:

The case where the abstract population is well-defined vs. not.

Also:

Abstract population discrete vs. continuous.

Before examining the crossings of these distinctions and trying for examples of each combination: is (1) really about abstract vs. concrete? Or is it rather about whether the object under discussion is itself part of the abstract population? You might, e.g., think of 'actual songs' as non-spatial but temporal and created, and thus hold an actual song to be distinct from its "abstract nature" or whatever, the latter being platonic (uncreated, non-temporal) - a space of "song-patterns".

Thursday, 11 December 2014

On Negation and Necessities about Contingent Existents

This is a long, wide-ranging, difficult to understand post. It will be easier to understand in connection with other posts, some of which already exist and are linked to, some of which have yet to come.

There is an irritating issue with some typical examples of the necessary a posteriori. This issue has to do with existence, negation and presupposition. The purpose of this post is to investigate what our options are with respect to this issue.

Kripke raises the issue and says some things about it in Lecture III of Naming and Necessity:

One qualification: when I say 'Hesperus is Phosphorus' is necessarily true, I of course do not deny that situations might have obtained in which there was no such planet as Venus at all, and therefore no Hesperus and no Phosphorus. In that case, there is a question whether the identity statement 'Hesperus is Phosphorus' would be true, false, or neither true nor false. And if we take the last option, is 'Hesperus = Phosphorus' necessary because it is never false, or should we require that a necessary truth be true in all possible worlds? I am leaving such problems outside my considerations altogether. If we wish to be somewhat more careful, we could replace the statement 'Hesperus is Phosphorus' by the conditional, 'If Hesperus exists then Hesperus is Phosphorus', cautiously taking only the latter to be necessary. Unfortunately this conditional involves us in the problem of singular attributions of existence, one I cannot discuss here.

So, the issue lies, in the first instance, with canonical Kripkean examples of the necessary a posteriori involving names referring to objects which exist contingently. Besides the example of empirical identity statements, this also affects, for example, subject-predicate statements ascribing what we might think of as necessary properties to contingently existing individuals, e.g. 'N is spatiotemporal' where 'N' names some physical object.

Kripke's Gappy Option

Since Kripke is talking of necessity in terms of truth-values at possible worlds, the issue for him involves the question of truth-value gaps. If the cases in question fall into truth-value gaps when their putative referents don't exist, then we can take the option of using 'necessary' to mean 'not false in any possible world', and these cases come out necessary without having to replace them with conditionals whose antecedents assert the existence of the putative referents. Call this 'Kripke's gappy option'.

Kripke's gappy option is quite open to controversy, since the idea that such sentences fall into truth-value gaps when their putative referents don't exist may be, and has been, resisted. If there is no King of France, is 'The King of France is bald' false (as Russell held), or neither true nor false (as Strawson held)? If there is no Santa, is 'Santa Claus came to my house and spoke to me yesterday' false, or neither true nor false? I am not sure that this is a sensible or important question – isn't there perhaps room for quite harmless stipulation either way here?, and isn't there room to quite harmlessly just not care (compare “don't care cases” in computer science)? – but for what it's worth, I am inclined to think it's more plausible that the definite description case is neither true nor false, than it is that the Santa case (a proper name case) is neither true nor false. It seems very natural to me to call the Santa sentence false. And since it is proper name cases that we have to do with, Kripke's gappy option seems predicated on something quite open to doubt and controversy.

The Conditionalizing Option

The other option Kripke identifies is to give up the idea that 'Hesperus is Phosphorus' and the like are strictly speaking necessary, and to replace these examples with conditionals like 'If Hesperus exists, then Hesperus is Phosphorus'. Call this 'the conditionalizing option'. Kripke shies away from this, saying that it 'unfortunately' involves us in the problems of singular existence attributions. To contemporary philosophers, this probably doesn't seem like much of an obstacle; OK, so there might be difficult philosophical problems pertaining to singular attributions of existence, but surely we can understand and legitimately use them, and so this strategy doesn't really involve us in the problems of singular existence attributions in any urgent way. It seems that things looked different when Kripke was lecturing, however – in large part because those very lectures had not yet had their great effect. The above-quoted passage continues thus, shedding light on this:

In particular, philosophers sympathetic to the description theory of naming often argue that one cannot ever say of an object that it exists. A supposed statement about the existence of an object really is, so it's argued, a statement about whether a certain description or property is satisfied. As I have already said, I disagree. Anyway, I can't really go into the problems of existence here.

The conditionalizing option is more open to us, however, since singular existence statements are now widely conceded to be legitimate and understandable, and furthermore because I do go into the problems of existence, and try to deal with them (for a start, in this post) – and so, to any extent that the conditionalizing option does involve us in these problems, that isn't a bad thing at all, since they are being dealt with.

So the conditionalization option is viable. But is it the only option? We may feel that there is another – that, by construing or modifying our account of necessity in some simple way (which may take some finding), we can have 'Hesperus is Phosphorus' itself come out necessary.

This is somewhat desirable, since a lot of people call that proposition necessary, without any implicit intention to really be talking about the conditionalized version, and it seems more plausible that they have their concepts arranged in a way that makes what they say true, than to suppose that they are simply mistaken. But even apart from that, and apart from any considerations in favour of preferring an account on which 'Hesperus is Phosphorus' comes out necessary, it is instructive to see whether and how we might have one. If we get one, we've just enriched our conceptual resources – we then have (at least) two notions available, closely related, which we can use 'subjunctively necessary' for – or we can use two different terms. (We may ask which one best fits most extant uses of the relevant terminology in the philosophical literature, but I can't see that this is an especially important question.) We will now pursue this.

Options Arising on My Account of Necessity

I say that a proposition is necessary iff it is, or is implied by, a proposition which is both true and inherently counterfactually invariant.

In the context of my account of necessity, the issue we have been discussing does not come so inevitably upon the issue of truth-value gaps, since I do not give my account of necessity in terms of truth-values at possible worlds. Truth-values are involved, of course: to be necessary, a proposition must be true – it must be, or be implied by, a true and inherently counterfactually invariant proposition. But the bit which does all the special work, the notion of inherent counterfactual invariance, is not spelt out in terms of truth-values, but rather in terms of negation and the contents of counterfactual scenario descriptions: a proposition is inherently counterfactually invariant if it is such that, if one comes to believe it, its negation does not appear in any counterfactual scenario description permitted by one's system.

Thus, with the account given here, the issue becomes about negation and the space of counterfactual scenario descriptions permitted by a system. We will first consider the option of approaching the issue via negation, in particular, by disambiguating the reference to 'its negation' – the negation of a proposition – in the characterization of inherent counterfactual invariance rehearsed above. On one reading, the cases at issue will come out necessary, on another, contingent.

Following that, we will consider the option of approaching the issue via the space of counterfactual scenario descriptions held to be relevant to inherent counterfactual invariance, and considering a restriction on this space such that, if it is in place, the cases at issue come out necessary, and contingent otherwise. One reason for considering this as well as the (more natural, I think) negation approach is that the idea that 'not' is ambiguous, or even the idea that a proposition can be negated in more than one way, is controversial. I will defend this idea, but even given its correctness, it may be dialectically useful to have another approach available, and it is interesting in any case to see that there is such an alternative.

Internal and External Negation

What is the negation of 'Hesperus is Phosphorus'? Two sentences we might give are 'Hesperus is not Phosphorus' and 'It is not the case that Hesperus is Phosphorus'. Is there more than one natural reading for these sentences? That is, can we give them different natural readings, or give one of them more than one natural reading?

It seems we can. It seems particularly clear that we can give one natural reading to one of them, and another to the other: we can read the first as implying that Hesperus (and perhaps a distinct object Phosphorus) exists, and read the second as having no such implication. Consideration of cases involving empty names (i.e., where the relevant existence-implications will be false) gives this intuitive support; if someone says 'Santa's not happy', we might take this as saying that Santa's state of mind is not a happy one – that is, we might understand it to be saying something which, in order to be true, requires that Santa exists. If someone says 'It is not the case that Santa is happy', we might understand this as having no such requirement – roughly, as merely denying that it is true to say that Santa is happy. It may also be that one of these sentences can naturally be understood both ways, or that both can (whether or not we should say this will not concern us here).

So, it seems natural to suppose that we have here a difference between two kinds of negation of a proposition, and should therefore regard the phrase 'the negation' as ambiguous, or as failing to refer due to a failure of uniqueness. Let us for now use, in a rough way, the terms 'internal negation' and 'external negation' to talk about these two kinds, in advance of any particular account of how negation works in the different cases, or how the difference gets made, and without assuming that there aren't further distinctions to be made, for example between different sorts of internal negation. We will now consider some different strategies for accounting for this distinction.

Internal Negation as Dispredication

Looking at 'Santa is not happy' and 'It is not the case that Santa is happy', we might have the idea that the difference between them consists in this: that the first purports to name Santa and deny the predicate 'is happy' of him, much as 'Santa is happy' affirms it, whereas in the second case the negation applies to the whole proposition about Santa. Thus the first cannot be true without Santa existing, while the second can.

We may think of these two propositions as being of different logical forms. The first is of the subject-predicate form (or, we might say, a closely related dispredicational form) whereas the second is a truth-functional compound with one argument. On this way of construing the latter, the phrase 'It is not the case that' is taken as forming a symbol, so that the proposition may be rewritten 'Not-(Santa is happy)' or '~(Santa is happy)'.

Alternatively, we may think of external negation in natural language propositions like 'It is not the case that Santa is happy' as a special case of internal negation, namely where the subject is a proposition (or proposition-meaning, or whatever is apt to be the case) which is specified with a that-clause. And so while 'It is not the case that p' propositions are equivalent, and effectively the same as, those of the more artificial operatorial forms, we really only need internal negation, and the difference between 'Santa is not happy' and 'It is not the case that Santa is happy' is that the subject of the first is Santa, and the subject of the second is this 'It' – that Santa is happy. The first dispredicates happiness of Santa. The second dispredicates being the case of a certain proposition, or proposition-meaning (including both internal meaning and external projective relations), or whatever being-the-case-apt thing it is, and could be rendered without the 'It' as 'That Santa is happy is not the case'. (Note that not all similar-looking forms can easily be regarded as having the same kind of subject. For example, 'It is good that …'. It seems that for 'It is not good that p' to be true, 'p' needs to be true. We might say that the subject here is a state of affairs or a fact.)

Irrespective of this alternative regarding external negation, we have a problem with internal negation. The trouble with the dispredicational approach to internal negation lies in generalizing it. Recall that our aim is to spell out a distinction between two kinds of negation of a proposition, internal and external, so that cases like 'Hesperus is Phosphorus' come out necessary on our account if we use one sort of negation in our characterisation of inherent counterfactual invariance, and contingent if we use the other. It will be internal negation which yields the former verdict, external which yields the latter; since there are no counterfactual scenarios where Hesperus exists and fails to be Phosphorus, the internal negation of 'Hesperus is Phosphorus' should not be part of any counterfactual scenario description. But since there are counterfactual scenarios where Hesperus doesn't exist, the external negation can appear in descriptions of those.

For this strategy, as outlined, to work, it will have to be the case that every proposition has an internal and an external negation. For the notions of necessity and contingency, and therefore our special notion of inherent counterfactual invariance in terms of which we define them, are meant to apply (positively or negatively, and borderline cases aside) generally to all kinds of propositions.

The only other options I can see, short of denying modal status to some propositions of a non-borderline sort which seem to have modal statuses, are the following variations on the strategy as outlined: (i) simply stipulate some modal status for all truths and for all falsities for which there is no internal negation (or for which 'internal negation' is undefined), (ii) take a disjunctive approach to counterfactual invariance (and in turn necessity) by making the internal negation of the proposition in question the relevant thing when there is one, the external negation otherwise. Neither of these seems very appealing, and below we will encounter reasons for thinking that, in addition to seeming ad hoc and messy, they do not behave in any satisfying way: (i) will wind up giving intuitively wrong answers about a great many propositions to which the dispredicational account of internal negation does not apply (such as quantifications, to anticipate), and (ii) will yield an account which behaves in a way which intuitively seems unsatisfyingly non-uniform, even if every verdict it gives is correct on some natural, intuitive understanding of the modal notions.

So, how might we extend the dispredicational account of the distinction between internal and external negation so that it gives all propositions both an internal and external negation?

The case of external negation presents no difficulties on this score, whether or not we regard it as a special case of internal. Every proposition can have the truth-functional negation operator applied to it, and every proposition (or proposition-meaning, or whatever) can be made the subject of an 'It is not the case that p' proposition.

But what are the internal negations of propositions which do not seem to be of the subject-predicate form supposed to be? We will consider three classes of such propositions: relational propositions, truth-functions, and quantifications.

Relations. We began by considering 'Hesperus is Phosphorus', which is often construed relationally, as an ascription of the identity relation. We are perhaps able to stave off, as far as identity statements go, the problem of extending our dispredicational account of internal negation; in other posts we considered issues which arise when identity is construed as a relation, and offered an alternative construal of identity statements as subject-predicate propositions of a special kind. But that is small comfort, since we must face the issue anyway – we will certainly need to be able to use our account of internal negation to rule some relational statements about contingently existing individuals to come out necessary, others contingent, others impossible, others contingently false. (Consider: 'Hesperus is in the same location as Phosphorus' - necessary if colocation is reflexive, 'Hesperus is near Mars' - contingently true on a suitable construal of 'near', 'Hesperus is in a different place from Phosphorus' – impossible, 'Comet A fell to Hesperus' – could be contingently false.)

So, what might the internal negations of 'John loves Mary' and 'John told Paul about Mary' be?

One simple enough option is to treat these as subject-predicate propositions, with 'John' as the subject, and 'loves Mary' and 'told Paul about Mary' as the predicates, and then treat their internal negations as simple dispredications. But the results will not require Mary (and in the second case, Paul as well) to exist, as they might if construed differently. On different ways of construing them (according to whether we have just one subject, or two or more, or equivalently how we construe the predicate (how many places, and where)) their counterfactual invariance status may vary. But if the positive statements being negated all imply each other under these various construals, even if their negations don't, then these differences will not “percolate up” to necessity and other modal statuses. Nevertheless, we have got ourselves into a messy situation, and the dispredicational approach is not looking very appealing, even if it can be argued to happily deliver the desired results. I will try to unpack this a bit, before moving on to consider how the dispredicational approach to internal negation might be extended to truth-functions.

Suppose 'If a and b exist, then aRb' is necessary on an external negation construal of counterfactual invariance, and suppose a and b are distinct, contingently existing and independently existing things. Now, we want a dispredicational construal of the internal negation of 'aRb' such that this comes out necessary when we make that the relevant negation for counterfactual invariance. Since a and b exist contingently and independently of each other, we can divide counterfactual scenarios into four kinds. Using 'a' in this sentence to mean 'a exists' and '~a' to mean 'a does not exist', we have scenarios in which (i) a & b, (ii) ~a & b, (iii) a & ~b, and (iv) ~a & ~b.

Now, let us consider what happens when we take 'a' in 'aRb' as subject and 'Rb' as predicate, i.e. when we construe 'aRb' as 'a is (R b)'. The internal negation of this, which in effect says that a lacks the (non-contingently existing) property of bearing R to b, can appear in descriptions of scenarios of type (iii); when b doesn't exist but a does, a must lack that property, since possessing it would require b to exist. And so on this constual, 'aRb' is not counterfactually invariant – its internal negation does appear in counterfactual scenarios permitted by the system to which it belongs.

On the other hand, when we take a and b both as subjects, or for clarity and neatness's sake the ordered pair <a, b>, i.e., when we construe 'aRb' along the lines of '<a, b> (falls under R)', we get a different result. Instead of saying that a lacks the property of being R-related to b, this says in effect that the pair of things a and b lack the property of falling under R. So this cannot appear in scenarios of type (iii), since that pair doesn't exist in those scenarios. On this construal, therefore, 'aRb' is counterfactually invariant.

(Note that this divergence doesn't show up with true identity statements, even when we do construe them relationally, since in their case the categories (ii) and (iii) will be empty.)

It may seem that, since 'aRb' differs on these construals with respect to counterfactual invariance status, it must differ with respect to necessity vs. contingency as well. After all, this is not one of the disjunctive sorts of cases which was seen to motivate the closure of necessity under implication in my account of necessity, and so it may seem like propositions like 'aRb' are necessary only if they themselves are counterfactually invariant, and since 'aRb' isn't counterfactually invariant on one of its construals (namely 'a is (Rb)'), it isn't necessary on that construal either.

This can, and arguably should, be resisted, on the grounds that the '<a, b> (falls under R)' construal implies the 'a is (Rb)' construal. Indeed, they very arguably imply each other, even though their dispredicational internal negations do not. And so, while 'aRb' on the 'a is (Rb)' construal is not counterfactually invariant, it is implied by a proposition ('aRb' on the '<a, b> (falls under R)' construal) which is both counterfactually invariant and true, so it comes out necessary.

Nevertheless, all this complication is unpleasant – these multiple ways of grouping relational statements into subject, or subjects, and predicates don't seem very instructive, and what they are capturing might plausibly be expected to be capturable in a more illuminating way. (To anticipate, I will end up suggesting that we do this by considering the way a proposition may be construed as having more or less presuppositions.)

Truth-functions. This could perhaps be dealt with by laying it down that, to obtain the internal negation of a truth-functional proposition, one must translate it into disjunctive normal form (a disjunction of conjunctions of non-truth-funcional propositions or negated non-truth-functional propositions) or conjunctive normal form (a conjunction of disjunctions of atomic non-truth-functional propositions or negated non-truth-functional propositions), and then give each negated non-truth-functional proposition an internal reading.

For example, the internal negation of 'p or q', then, will be, taking the option of disjunctive normal form, '(p and q) or (<p's internal negation> and q) or (p and <q's internal negation>)'.

Presupposing that internal negation is defined for all non-truth-functional propositions, we can extend the definition to truth-functions in this artificial way. The artificiality of this procedure compared with the account of internal negation we will eventually settle on is a reason for favouring the latter, but this will be overshadowed by problems arising in the consideration of quantifications below.

Quantifications. So far, we have been able to wangle, using fairly elaborate means, extensions of the dispredicational account of internal negation to relations and truth-functions. But the account founders more seriously on quantifications.

Consider, for example, the proposition 'There are feathers in Robin Hood's cap'. It seems we can say 'There are no feathers in Robin Hood's cap' and read this as requiring Robin Hood's existence – effectively, asserting the featherlessness of Robin Hood's cap. And on the other hand it seems we can say 'It is not the case that there are feathers in Robin Hood's cap', and read it as making no such requirement.

(It may be protested that 'There are no feathers in Robin Hood's cap' can be dealt with by regarding 'no' not as a negation sign, but as like a number-term, making the proposition effectively the same as 'There are zero feathers in Robin Hood's cap'. That is plausible enough for this particular case, but consider 'There aren't feathers in Robin Hood's cap', or this exchange: A: 'There are feathers in Robin Hood's cap', B: 'There are not!'.)

I do not think we can extend the dispredicational approach to internal negation to cover this case, but let us consider two routes which may present themselves: (i) treating quantifications in a way inspired by Frege and Russell as second-order predications, and (ii) treating quantifications as infinite conjunctions or disjunctions.

Both Frege and Russell had a version of what Scott Soames calls a 'properties of properties' analysis of quantification. The basic idea, in formal logical terms, is first to abstract a property from the open sentence bound by the quantifier and then to see the quantifier itself as predicating of that property, in the case of universal quantification, the property of being possessed by everything, or in the case of existential quantification, the property of being possessed by something.

In simpler terms, 'Everything is F' (i.e. 'Everything has the property F') is analyzed along the lines of 'being F is possessed by everything', i.e. a subject-predicate proposition. Or to take a slightly more complicated example, 'All men are mortal' is analyzed along the lines of 's is P', where 's' denotes the set of things which are such that, if they are men, then they are mortal, and 'P' is a predicate true of properties which are possessed by everything.

Brilliant and insightful as this is, it doesn't meet our present needs, since the subject here will always be a property. What we needed was an ability to make contingently existing things whose existence is presupposed by the proposition in question the subjects. So a proposition like 'There are no feathers in Robin Hood's cap', if this is taken to presuppose the existence of Robin Hood, cannot be rendered in this way, at least not without regarding the property of being a feather in Robin Hood's cap to be a contingently existing thing, which would be controversial and difficult. (We will come back to this example below and discuss it a bit further, when we consider and reject the option of a disjunctive approach to inherent counterfactual invariance, whereon the internal negation is what is relevant when there is one, the external negation otherwise, such as in quantificational cases.)

What about the second option of analyzing quantifications as infinite truth-functional propositions – universal quantifications as infinite conjunctions, and existential quantifications as infinite disjunctions? It is a commonplace in contemporary analytic philosophy that this doesn't work – the treatment of them as such by the Tractatus, for example, is widely regarded as one of the fundamental flaws in the Tractarian system.

Why exactly it doesn't work – or, how best to argue that it doesn't work – is actually not nearly so clear and well-established as that it doesn't work. I will not try to give a full treatment of this matter here, but I will briefly look at one quite natural but bad argument that it doesn't work, before discussing why it doesn't work from my point of view.

The natural but bad argument I want to consider is instanced by Richard Holton and Huw Price in 'Ramsey on Saying and Whistling: A Discordant Note', where they consider a reconstruction of one of Ramsey's arguments for treating quantificational sentences as not being (or expressing) genuine propositions. The argument proceeds via an argument that they cannot be treated as infinite conjunctions or disjunctions. Here is the reconstruction, with a good criticism following it:

If we treat universally quantified sentences as expressing propositions we will be forced to see them as equivalent to conjunctions which, since they are infinite, ‘we cannot express for lack of symbolic power’. But that is no good: ‘what we can’t say we can’t say, and we can’t whistle it either’.

Is this argument convincing? At first sight, apparently not, for consider an analogy. What do you get if you divide one by three? If you try saying the result as a decimal expansion you will never stop: 0.33333... However, that doesn’t mean that you can’t say it, only that you need to express it in a different way: as the fraction 1/3.

Holton and Price go on to consider another interpretation of Ramsey, which brings the argument closer to other arguments he gave for the same conclusion. We won't bother with that; our motive was largely to bring into focus that appealing to our finitude, our limitations, in resisting the infinite truth-function analysis of quantifications isn't the point.

What is the point? From my point of view, we can distinguish eight angles from which to see that the truth-functional analysis of quantification fails. For four of these (namely (1), (2), (6) and (8)), I will draw on Wittgenstein's discussion of 'Generality' in Philosophical Grammar (part II, section II, pages 257 – 279), which includes a subsection called 'Criticism of my former view of generality', this former view being the truth-functional analysis of quantification as given in the Tractatus.

(1) Phenomenology of sense: It just doesn't seem like a simple existential quantification (for example), such as 'There are horses', means the same as some long, or infinite, disjunction. We feel like the particular disjuncts in such a disjunction deal with cases, and that these cases to not enter into the sense of the quantification. The quantificational proposition is simple, whereas the long disjunction is complicated.

Here are three passages from Philosophical Grammar which express this point:

Let us take the particular case of the general state of affairs of the cross being between the end-lines.

|--X------| |-----X---| |-------X-| |---X-----|

Each of these cases, for instance, has its own individuality. Is there any way in which this individuality enters into the sense of the general sentence? Obviously not. (p. 257)

There is one calculus containing our general characterization and another containing the disjunction. If we say that the cross is between the lines we don't have any disjunction ready to take the place of the general proposition. (p. 258)

Suppose I stated a disjunction of so many positions that it was impossible for me to see a single position as distinct from all those given; would that disjunction be the general proposition (Ex).Fx? Wouldn't it be a kind of pedantry to continue to refuse to recognize the disjunction as the general proposition? Or is there an essential distinction, and is the disjunction totally unlike the general proposition?

What strikes us is that the one proposition is so complicated and the other so simple. … (p. 262)

(2) Favourable cases are clearly special: Cases which do seem to have justice done to them by the truth-functional analysis of quantification are clearly special – they clearly fulfil conditions which aren't generally fulfilled by quantifications. So, by applying the Wittgensteinian method (made explicit later, in the Investigations) of considering 'a language-game for which this account is really valid' (PI, 48), we will be able to see that the account is not generally valid, since its validity in the favourable cases turns on features not shared by all quantificational propositions.

Of course it is correct that (Ex)Fx behaves in some ways like a logical sum and (x)Fx like a product; indeed for one use of the words “all” and “some” my old explanation is correct, - for instance for “all the primary colours occur in this picture” or “all the notes of the C major scale occur in this theme”. But for cases like “all men die before they are 200 years old” my explanation is not correct. (p. 268)

These amenable cases are clearly special; what makes them amenable is the fact that the concept terms 'primary colour' and 'note of the C major scale' determine, by their very meaning (or 'grammar'), their extensions. Any term used in such a way that something other than {C, D, E, F, G, A, B} (where these letters are taken as names of notes) is its extension simply wouldn't express the concept of a note of the C major scale. Clearly, not all quantifications involve such concepts – for example, the one about men all dying before the age of 200 doesn't. From this we can see that the truth-functional analysis isn't generally valid.

(3) The “that's all” problem: Suppose there are just three objects, a, b and c. (This is just for simplicity's sake – the problem I which will now emerge could be stated for the case of reality, too.) Now, on the basic truth-functional analysis of quantification, 'Everything is F' means 'a is F and b is F and c is F'. But suppose someone believes falsely in a fourth object, which they call 'd'. Surely believing in an object which doesn't exist doesn't stop them correctly understanding 'Everything is F', and using it with its actual meaning. But if they thought d wasn't F, they would deny that everything is F, but they may consistently accept that a is F and b is F and c is F.

This actually enables us to see two problems: the present “that's all” problem, and the next problem on our agenda, the problem of meaning varying with the domain.

The “that's all” problem is this: the conjunction above doesn't capture the meaning of 'Everything is F' because it leaves it open whether there are other objects not mentioned by it – it lacks a “that's all” implication.

This shows the basic truth-functional analysis of quantification, exemplified above, to be wrong. But what if the “that's all” problem could somehow be solved?

There are three sorts of attempts at solutions to consider:

(i) Attempts which deny the need for quantification propositions, upon analysis, to say anything to the effect that “that's all”.

(ii) Attempts to modify the analysis so that quantificational propositions somehow have a “that's all” implication, while preserving non-circularity.

(iii) Attempts to modify the analysis by adding a “that's all” clause, without trying to avoid circularity.

Wittgenstein in the Tractatus is the representative of (i) which I have in mind. The dilemma I propose for this approach is: either there is something deeply right about Wittgenstein's contention that it is nonsensical to name a bunch of objects and say that they are all the objects that there are, or there isn't.

If there is (as I suspect), then this just shows the whole truth-functional approach to quantification to be wrong: many quantificational propositions clearly do say everything they try to say. While it may be important to see that certain “that's all” type propositions are really pseudo-propositions, this appearance of an unsayable element which we may try, and inevitably fail, to express in a proposition, obviously doesn't percolate up to quantificational propositions, as it would if the analysis were correct. It is simply beyond the pale to say that all quantificational propositions involve this sort of “nonsense”, or this attempt to say what can only be shown, or whatever it is, and equally beyond the pale to say that they show something along “that's all” lines which we may try and fail to say – to bite the bullet on this would be to embrace a cripplingly narrow view of the typology and functioning of propositions.

If there isn't, then this sort of attempt is misguided through-and-through.

The second sort of attempt, modifying the analysis to get a “that's all” implication, but without circularity, seems to me to be a non-starter. It may perhaps be argued that this might just be due to a failure of imagination on my part, but I'm inclined to think this isn't so, and that considerations along the lines of the Paradox of Analysis would apply to any materially adequate attempt: any linguistic device able to pull off the trick of giving you a “that's all” implication would thereby qualify as a quantificational device, and so no analysis pulling off this trick could possibly be non-circular.

The third sort of attempt is interesting; perhaps an analysis of quantification in terms of a truth-function with a “that's all” clause tacked on may be true, even if the “that's all” clause involves quantification, making the analysis circular; it may be a non-vicious circularity. Furthermore, the analysis may answer to the task of explaining how quantificational propositions may have dispredicational internal negations: the negation would now apply to a truth-function involving (what may be unnegated) quantification, rather than directly to a quantification, and so the artificial strategy suggested above for getting dispredicational internal negations of truth-functions may apply.

This third attempt is in many ways the most promising – the others seem quite hopeless. At least we get an analysis here, something which we can work with and assess, and one which clearly doesn't suffer from the “that's all” problem. But this attempt brings out the fact that our example above of someone who believes in something which doesn't exist, but still gives quantifications the right meaning, shows up two further problems: the problem of excess content, and the problem of meaning varying with the domain. These show the truth-functional approach to be wrong, with or without a circularity-making “that's all” clause.

(4) The problem of excess content: with the “that's all” problem above, we were entertaining considerations which suggest that the truth-functional approach to quantification yields analyses which aren't logically strong enough in a certain respect: they fail to imply that there is nothing else in the world not covered by the proposition. But there is an opposite problem as well: the analyses yielded are too strong in certain respects, having implications which the propositions they are meant to be analyses of do not have.

For example, 'All men are mortal', if analyzed as an conjunction with a conjunct for every thing, saying that that thing is either mortal, or not a man, then it would involve, for example, a conjunct saying: Venus is either mortal, or not a man. And this implies that Venus exists. But 'All men are mortal' doesn't imply that Venus exists, so the analysis is wrong.

This holds whether or not we have a “that's all” clause. If we do, the problem just gets worse: not only is 'All men are mortal' falsely predicted to imply, of any existing thing you care to mention, that that thing exists, it is also falsely predicted to say that there is nothing besides what it names – in other words, it is predicted to specify which things exist, which it surely does not do (no matter how deeply you analyze it!).

(5) The problem of meaning varying with the domain:

This problem is, in the abstract, that a truth-functional analysis of quantification falsely predicts that the meaning of quantificational propositions varies with the domain.

Suppose (again, for simplicity's sake) that there are just three things, a, b and c. On the truth-functional approach, 'Everything is F' can now be analyzed as 'a is F and b is F and c is F' (or perhaps this with a “that's all” clause added).

The problem can now be seen from an epistemic (or doxastic) angle: suppose someone in this three-object world believed falsely in a fourth object, d, then they wouldn't accept the analysis, and yet intuitively they might understand 'Everything is F' just as well as we do, be just as good at analysis, and mean the exact same thing by it.

If we take a temporally dynamic view of existence, it can also be seen from the angle of the domain changing over time: 'Everything is F' doesn't mean 'a is F and b is F and c is F', since, if something new, d were to come into existence and come to our attention, and if we didn't know whether it was F yet, we wouldn't say 'Everything is still F, according to what we used to mean by that'. Rather, we would bring the question of whether d is F to bear on our proposition 'Everything is F' without it having changed its meaning.

What about if we had a “that's all” clause? In that case, if the analysis were right, and we carried on using 'Everything is F' with the same old meaning (not changing it to cover d), the mere existence of d ought to make us judge it false (since you can no longer say “that's all” of a, b and c taken together). But in fact, we don't change its meaning, but we don't just it false just in view of d's existence either.

Finally, we can see the problem from a counterfactual or “other worlds” angle: our proposition 'All men die before the age of 200', with the meaning it has, may be true of circumstances in which some things which actually exist don't exist (i.e. where the domain varies). But if the truth-functional analysis were right, it would come out false: if some actually existing thing a failed to exist in these circumstances, then in the analysis of 'All men die before the age of 200', the conjunct which covers a, and says of it that it either dies before 200 or isn't a man, would come out false, falsifying the whole. But that is clearly not how the proposition analyzed works: we can speak of counterfactual scenarios in which all men die before the age of 200, but in which you or I don't exist.

(6) The problem of the relevant propositions not existing: On this approach, the infinite conjunctions and disjunctions we would need just don't exist, or even cannot exist – and not just because they are infinite. Rather, also because they would have to contain propositions which name objects, where there just aren't any such propositions, and perhaps couldn't be.

Here is Wittgenstein's expression of this point in Philosophical Grammar:

Criticism of my former view of generality

My view about general propositions was that (Ex)Fx is a logical sum and that though its terms aren't enumerated here, they are capable of being enumerated (from the dictionary and the grammar of language).
For if they can't be enumerated we don't have a logical sum.


Of course, the explanation of (Ex)Fx as a logical sum and of (x)Fx as a logical product is indefensible. It went with an incorrect notion of logical analysis in that I thought that some day the logical product for a particular (x)Fx would be found. (p. 268)

This point – which is quite well known in a slightly different guise, namely as a problem for substitutional quantification (which I will discuss in a future post) – is likely to be controversial, since it relies on taking a certain kind view of the nature and existence of propositions. This kind of view may be called a “down to earth” view: propositions are the sort of things which come out of our mouths and get written down, or types thereof.

Many philosophers think about propositions and the like in ways which are not down-to-earth in this sense. If, for example, we conceive of a name with a referent in abstract mathematical terms, as for example an ordered pair consisting of an abstract typographical object and an object (the referent), then this problem doesn't really come through - although another, Benacerraf-esque problem arises: what's to say which “names” are chosen for the RHS of the analysis, since if the pair <the letter A, n> exists, where n is some highly obscure object which no one will ever really name, and perhaps couldn't, then so too does the pair <the letter B, n>.

(7) Cardinality problems: If there exists a non-denumerable infinity of real numbers, for example, then it may be argued that there are not enough names and propositions to go around – and this isn't due to our finitude: even infinitely many names and infinitely many propositions about infinitely many objects may not be enough, even on an abstract, non-down-to-earth view (in the sense of point (6) above), if there are only denumerably many names.

(8) The problem of domain indeterminacy: The “universal domain”, as well as various subdomains of discourse, cannot (without significant idealization) be regarded as constituting a determinate totality. Many domains are such that you can talk literally, without making any idealization, about a determinate, non-fuzzy set which collects all and only the elements of the domain together. This may lead us to fail to see that there really is no such thing in the universal case, and in many subdomains as well. Despite the idea of a determinate totality being ultimately chimerical here, that doesn't mean we can't quantify over all things, or use quantificational propositions in connection with subdomains not constituted by determinate totalities.

From Philosophical Grammar:

[W]hat matters, I believe, isn't really the infinity of the possibilities, but a kind of indeterminacy. Indeed, if I were asked how many possibilities a circle in the visual field has of being within a particular square, I could neither name a finite number, nor say that there were infinitely many (as in a Euclidean plane). Here, although we don't ever come to an end, the series isn't endless in the way in which | 1, ξ, ξ + 1 | [Wittgenstein's sign for the series of positive integers] is.
Rather, no end to which we come is really the end; that is, I could always say: I don't understand why these should be all the possibilities. – And doesn't that just mean that it is senseless to speak of “all the possibilities”? (p. 276)

This seems closely related to the Tractarian idea, which came in in connection with point (3)(i) above, that you can't actually list a bunch of objects and sensically say “that's all” of them.

We have now seen eight reasons why quantificational propositions cannot be analyzed truth-functionally.

We now conclude, then, that there is no satisfactory way to extend the dispredicational approach to characterising internal negation to the case of quantificational propositions – it cannot be done with them as they are, and they cannot be analyzed into a more amenable form either.

Here is a good place to say something about what is wrong with a disjunctive approach to selecting the negation relevant to inherent counterfactual invariance status, i.e.: take the internal negation when there is a suitable one, otherwise (such as in the case of quantifications) take the external negation. Then one reading of 'inherently counterfactually invariant' will just involve external negation, and the other will be this disjunctive one. This may be coherent, but it is complicated, and doesn't behave in any uniform, satisfying way: the point of the latter sort of reading was to get 'Hesperus is Phosphorus' to come out necessary without having to posit truth-value gaps or conditionalize it. But there will be true quantificational propositions which, by parity, we ought to count as necessary along with 'Hesperus is Phosphorus', but which will come out contingent. For example, 'All things identical to Hesperus are identical to Phosphorus'. (This could arguably be construed so as not to require the existence of Hesperus or Phosphorus, but still, it seems clear that it can be construed as presupposing their existence, so that its internal negation ought to presuppose their existence as well.)

The Presuppositional Account

I propose we account for the distinction between internal and external negation is in terms of the notion of presuppositions; 'Hesperus is Phosphorus', intuitively, doesn't actually say that Hesperus/Phosphorus exists, but presupposes it. We can see the internal negation as preserving this presupposition, and the external negation as cancelling it. Rather than thinking of this as some kind of effect of the two sorts of negation, which we would have to do anyway if we adopted another account of the internal/external negation distinction, we should use this to characterise the two sorts, and the difference between them.

We can be more nuanced too and differentiate between, not just cases where all presuppositions are cancelled and cases where none are, but cases where some presuppositions are in force and others aren't. In this way, we can capture what was awkwardly captured on the dispredicational approach by means of different groupings of subject(s) and predicate.

This approach to making a meaning-distinction between two sorts of negation based on the notion of presuppositions is taken up, in a particular version, by Pieter Seuren in his papers 'Presupposition and Negation' and 'Presupposition, Negation and Trivalence'.

Seuren's approach involves a third truth-value, since Seuren wants both internal and external negations to be expressible as unary truth-functional propositions. Propositions whose presuppositions fail are 'radically false', while propositions whose presuppositions are met but which still aren't true are 'minimally false'. This then leads to several options and complications which Seuren tackles undaunted.

I want to abstract away from this way of going. Why, for example, do we need to regard internal negation as a truth-functional propositional operator? If we don't, then do we really need three truth-values, or even gaps for that matter? For example, can't we just distinguish between cases of what Seuren calls the 'radically false' and the 'minimally false' by taking directly about presuppositions, or the truth-values of their internal negations, while calling them all just 'false'?

Our conclusion, then, is simply that we should distinguish two kinds of negation, internal and external, and that we should characterise this distinction by means of the notion of presupposition: internal negation preserves (some or all) presuppositions, and external negation cancels them.

Negation and Ambiguity

Some linguistic constructions may quite unambiguously be internal or external negations, other constructions may tend to signal one or the other, and still other constructions may not carry anything in themselves to suggest one or the other, this being left to context.

Since I do not want to get deep into the linguistic details of how things are in these respects, it will be difficult to discuss questions of potentially controversial ambiguities implied by this approach with any concreteness. For example, should we say 'not' is ambiguous on this approach? Or can we avoid this by locating the difference, not in the meanings of expressions, but their form or mode of composition? (Or even their subject matter: recall in this connection the idea adumbrated above of construing external negation expressed with 'It is not the case that' as dispredicating being the case of a proposition (or proposition-meaning) referred to by 'It' and the 'that' clause.)

Without going into the details of negation-expressions themselves (like 'not'), we may still consider questions of ambiguity in two ways: (i) by considering, in the abstract, the question of how any ambiguities which may arise on this approach may be made sense of and legitimized, and (ii) by considering the “meta” but concrete case of the expression 'The negation of …' where the dots are filled in with an expression referring to a proposition.

Here is what Seuren has to say about negation and ambiguity:

The ambiguity of negation in natural language is different from the ordinary type of ambiguity found in the lexicon. Normally, lexical ambiguities are idiosyncratic, highly contingent, and unpredictable from language to language. In the case of negation, however, the two meanings are closely related, both truth-conditionally and incrementally. Moreover, the mechanism of discourse incrementation automatically selects the right meaning. These properties are taken to provide a sufficient basis for discarding the, otherwise valid, objection that negation is unlikely to be ambiguous because no known language makes a lexical distinction between the two readings.

While Seuren and I are in agreement that we can profitably speak of an ambiguity between internal and external negation, I want to say that the case of negation is not so special as these remarks of Seuren's may make it seem.

Indeed, the topic of negation just provides another case, or bunch of cases, of ambiguities which fail the Kripke test (roughly: when faced with the question of whether an expression is ambiguous, look at whether other languages use two different expressions instead of one – if not, that casts doubt on the ambiguity).

I will dicuss ambiguities failing the Kripke test, in connection with semantic granularity, in a future post, and from that discussion it will be clear that there is nothing which isn't 'ordinary' or 'normal' here (Seuren's words for what the case of negation isn't), and that the Kripke-test-based objection he considers is not 'otherwise valid': there is a large class of cases for which the Kripke test is valid, and a large class for which it is not, and granularity considerations can help us see what characterizes these classes.

Restricting the Space of Scenarios

There is an alternative to the approach of getting 'Hesperus is Phosphorus' and the like to come out necessary on my account by defining inherent counterfactual invariance in terms of internal negation. It is perhaps a bit less natural, but it may have an ecumenical advantage, in not requiring there to be an internal/external negation distinction.

Rather than defining inherent counterfactual invariance in terms of all counterfactual scenarios, as in:

A proposition is inherently counterfactually invariant iff it is inherently such that, if you come to believe it, its negation doesn't appear in any counterfactual scenario description.

We can say:

A proposition is inherently counterfactually invariant iff it is inherently such that, if you come to believe it, its negation doesn't appear in any counterfactual scenario description according to which the presuppositions of that proposition are met.

An Analogous Issue with the Contingent A Priori, Treated Differently

Recall that the issue we have been looking at here affect necessary truths about contingently existing things. There is an analogous issue with cases of the contingent a priori. When a name, say 'N', has been stipulated to refer to the concrete particular, if there is one, which fulfils certain conditions F, it is often said that the proposition 'N is F' will then be contingent a priori. But this statement entails that N, some concrete particular, exists (and is F), and surely this cannot be a priori. In this case, I think there is no very natural other way, and so I simply deny that such propositions are a priori, speaking strictly. (There is of course room for a slightly artificial use of 'a priori' defined in terms of a more natural use with the express purpose of making such cases come out a priori – e.g. something is a priori in this special sense iff its conditionalization (in the sense of the conditionalizing option discussed above) is a priori.) 'If N exists, N is F', on the other hand, will be genuinely contingent a priori.

Conclusions

Our main conclusions are as follows. We can distinguish two construals of inherent counterfactual invariance, so that on one 'Hesperus is Phosphorus' is not strictly speaking necessary (while 'If Hesperus exists, then Hesperus is Phosphorus' is), and on the other it is. There are at least two viable ways to get the second construal (and so, you might say, we can really distinguish three construals, but two of them line up): (i) by means of a distinction between internal and external negation, where the former preserves presuppositions and the later cancels them, or (ii) by defining inherent counterfactual invariance, not in terms of all counterfactual scenario descriptions permitted by the system of language to which the proposition in question belongs, but rather in terms of the subset of permitted counterfactual scenario descriptions which describe scenarios in which the presuppositions of the proposition in question hold.

Along the way, we reached some other conclusions, which may be of independent interest. One of these was that the dispredicational approach to the internal/external negation distinction cannot be satisfactorily extended to all propositions. In the course of seeing this, we also saw that quantificational propositions cannot be analyzed as truth-functions, and furthermore, we got a good look at why not, distinguishing eight angles from which it can be seen.