Saturday 2 August 2014

Two Concepts of Metaphysical Modality

Here I want to distinguish two concepts of metaphysical modality and then give two reasons for thinking that this is an important distinction.

One concept, which I will call the concept of metaphysical modality in the narrow sense, crucially involves the subjunctive/indicative contrast, or the contrast between considering a scenario as counterfactual versus considering it as actual, and focuses on the subjunctive/counterfactual side. (This is why Chalmers is able, in 'The Foundations of Two-Dimensional Semantics' and other papers, to choose 'subjunctive necessity' as his preferred term for metaphysical necessity in the narrow sense.) It concerns how things could have been in a very broad sense. And so we can help fix the concept with familiar Kripkean talk like 'To be sure, we don't know a priori that Hesperus is Phosphorus. Given far-out enough empirical revelations, that could turn out to be wrong. But given that we're not mistaken about this - given that Hesperus is Phosphorus - then it could not have been otherwise. It is a necessary truth that Hesperus is Phosphorus'.

The other concept, which I will call the concept of metaphysical modality in the broad sense, doesn't involve this contrast. It may be roughly characterized as modality which is neither epistemic nor somehow conventional. Modal facts which are the way they are irrespective of anything to do with our knowledge, and irrespective of any conventions we might have, are metaphysical modal facts. And we might want to throw in something about the modality not being restricted as well.

To illustrate the difference, consider a proposition like 'This typewriter cannot have two of its keys depressed simultaneously' - or, to avoid the idea that this may be a case of some tacitly restricted modality, 'This typewriter cannot in the course of its proper functioning have two of its keys depressed simultaneously'. This proposition clearly has a modal element. Also, this modal element appears to have little to do with knowledge or some convention we have set up. If the proposition is true, then the typewriter in question has this modal property - that of not being able to have two of its keys depressed simulteneously in the course of its proper functioning - in virtue of the way it is, not in virtue of our state of knowledge or any convention we have set up. And so we might want to say that the modality in question is metaphysical in the broad sense. But it seems not to be an instance of metaphysical modality in the narrow sense. The subjunctive, or the consideration of scenarios as counterfactual, doesn't come into the matter; it is, we might say, about what the typewriter can actually do, not what it might have done had things gone differently (even if, in this case, there is a one-to-one correspondence between actual and counterfactual possibilities).

Another example of a proposition involving a modality which we should say is metaphysical in the broad sense but not in the narrow, is 'It is possible to win a game of chess in five moves'. Here the object of interest is something abstract (the game of chess), whereas in the first example the object of interest was a concrete mechanical thing.

Why is it important to realize that there are these two different concepts of metaphysical modality? One reason is that it seems very likely to be relevant to solving problems about the varieties of modality, a topic whose difficulty has become steadily more apparent in the decades following Naming and Necessity.

Another reason, which has been even closer to my concerns, is its relevance for the project of trying to analyze or give an account of metaphysical modality in the narrower sense. For instance, the account of this which I have been developing involves a notion which clearly has a modal component.

The account, which I will post on soon, says that a proposition is necessary iff it is, or is implied by, a proposition which is both inherently counterfactually invariant and true. And the notion of inherent counterfactual invariance is cashed out in terms of the counterfactual scenario descriptions producible by the language system to which the proposition in question belongs. Not those which it actually does produce in its career, but those which it can. (A proposition is inherently counterfactually invariant iff its negation does not appear in any of these producible counterfactual scenario descriptions.)

The question now arises: does the presence of this modal element - which should be a good sign to anyone who, like me, is suspicious that there could be any such thing as a reduction of a modal notion to non-modal notions - make the account circular? 'Circular' in this context seems like a dirty word, but note that if the answer is Yes, that wouldn't mean that the account is no good at all; it would still be far from obvious or trivial. It could then perhaps be seen as a recursive definition, presupposing some cases as a base, and explaining the rest in terms of it. But still, Yes might seem like the wrong answer. I suspect it is. Separating metaphysical modality in the broad sense from metaphysical modality in the narrow sense opens up a promising way of supporting a No; the account deals with metaphysical necessity in the narrow sense - subjunctive necessity, necessity when considering-as-counterfactual - and appeals, on the right hand side of the 'iff', to a distinct species of metaphysical modality in the broad sense. On this understanding, there is no circularity - or to put it more politely, recursiveness - in the account at all. Of course, it doesn't supply us with a key for analyzing modality away altogether, as some attempts at analyzing metaphysical necessity in the narrow sense (without perhaps isolating that sense sufficiently clearly) have tried to do, but that should probably be seen as one of its more important virtues.


Chalmers, David J. (2006). The foundations of two-dimensional semantics. In Manuel Garcia-Carpintero & Josep Macia (eds.), Two-Dimensional Semantics: Foundations and Applications. Oxford University Press. 55-140.

Kripke, Saul A. (1980). Naming and Necessity. Harvard University Press.


  1. You spelled "simultaneously" wrong.

  2. I think you have done a very sophisticated job of providing a good description of the various modalities; I am rather interested in your notions of necessity though. Is there any such thing outside of our grammar and logic? What foundation do you have for using the concept at all?

    Empirically, we infer necessity because of our need for a narrative structure so we can relate to complex relationships, but despite all our work on the subject, we are really no further along the road then we were with Hume; we don't see it, cannot measure it, and cannot find any real foundation for a statement such as "there is necessity" because of course everything could be, as the phrase goes, de trop. We inherited ananke from the Greeks and our culturally fond of it, but it may simply be cognitively hardwired, as the great one said, to categorize impressions according to this explanation. We insist on the necessity of something according to logic, but logic is basically grammar and may not actually correspond conceptually with how it is at all; perhaps the complexity of the cosmos is such that, like Newtonian physics, it works heuristically for us, but does not really reflect the truth of things, only a kind of partial if coherent massive over simplification, or mere fallacy that for the second that we have as a species has seemed to work for us, but of course if we were around longer and/or knew more, we would see it is hopeless.

    I raise this because it seems your point is based on a range of "necessary" states and I would have to say that without a foundation for necessity, they really are not meaningful.

    If we follow traditional metaphysical thinking, we must differentiate between what "reason" can and cannot handle. In that category are (impressions of) objects that are orderable according to time and space, in other words empirical objects. Our knowledge of these objects is always partial not only because we never experience them directly (in a perceptual or metric sense) but also because we are always gaining more information about them through study, trial, and error. If we can trust our faculties, then we can say we have "knowledge" of these things, but we can never really get to the "truth" about them because our ability to know them is partial, and because they are always changing. But we use our science, our reason, and our cognitive equipment to deal with them and seem to be doing alright in the sense that we have ever increasing power over our environment based on our "knowledge" and this power is what we seem to be aiming at.

    The other class of "things" are those that are not orderable in space and time. We cannot use reason with these, according to Kant, unless it be "practical" -which is foolishness unless we admit that none of our necessities fit areas such as the realm of spirit (however broadly defined) the foundations of morality, the theme of being beyond those material "Dinge" we perceive. We have to go beyond our grammar here and that is a very uncomfortable place for all the left brain dominant folks who tend to think about these issues.

    If that is indeed the case, the notion of "subjunctive necessity" is really a somewhat problematic notion; does it not mean that we follow a grammar of our own to assess the necessity of things that are not? If we cannot really establish necessity among things that are; how is it we can seriously discuss the necessity of things that do not have being?

    Help me with this, thanks..

    1. Thanks very much for your praise.

      Unfortunately I do not know how to answer your questions and only have a slight understanding of what you are saying here. I think our styles of thinking are very different.

      I am glad that you found something of interest in the post. I will post more on my account in the near future, so look out for that. Also, I do have some reflections I might make public (a little further down the track perhaps) which may speak to what you are wondering about with 'outside of our grammar and logic', 'foundations' etc.

    2. Hey,

      Different styles of thinking should not preclude communication, so-let me try again in a more focused and concise way: I note that much of your argument is based on various kinds of necessity. What is your foundation for the proposition that anything is necessary? (My first question) -and, until I know how you base your argument for the existence of necessity (I discussed the various issues I see as a problem in my post) How do you, in addition to the proposition that something is necessary, make the argument that things that are not anything are necessary? This "subjunctive necessity" strikes me as a rather frail reed. If there is "necessity" than the necessary state of affairs must be; a non-being is unnecessary to, well, anything at all, isn't it? I am afraid I don't follow the chess analogy in connection with this question. Perhaps that is clearer. Thank you for your attention.

      (I do, by the way, freely admit that my writing style is a bit gnomic at first, but I reread the comment and think it is coherent enough; perhaps you could give it another look because I am interested in the way you address the questions I have. Thanks.)

    3. I'm sorry, I can't make head or tail of this. Pardon the late and empty reply.

  3. There has been a bit of discussion of this post on reddit (which I participated in). I will reproduce it here in case it's helpful or interesting to any readers:

    [–]ADefiniteDescriptionΦ 7 points 3 days ago
    You kind of touch on this already but I'm curious: why think modal notions ought to be reduced to non-modal ones? Say I'm an inferentialist, and I give an inferentialist-acceptable account of the modal terms that doesn't involve reducing these to other non-modal terms. Isn't that good enough?

    [–]tristanhaze[S] 2 points 2 days ago
    Hi! I don't think that modal notions ought to be reduced to non-modal ones. I'm not sure what it is I said that seemed to imply that. In fact, the following sentence from the post shows my attitude to be quite otherwise
    'does the presence of this modal element - which should be a good sign to anyone who, like me, is suspicious that there could be any such thing as a reduction of a modal notion to non-modal notions - make the account circular?'

    But thanks very much for reading! It's certainly hard to make one's views on these matters clear to everyone - and at this stage I'm mainly trying to make them clear to myself and other specialists - but I will keep trying!

    [–]ADefiniteDescriptionΦ 2 points 2 days ago
    Sorry, I only skimmed it briefly. I figured you weren't trying to argue that they ought to be reduced, but that the starting point was assuming that they ought to. I figured the charge of circularity to the non-reductionist account was supposed to be in favour of reducing modal to non-modal.

    [–]tristanhaze[S] 1 point 2 days ago
    Right, I understand, cheers.

  4. [–]mvalenteleite 3 points 3 days ago
    I don't think I get it. What's wrong with:

    Please clarify why do you think there is a different kind of metaphysical modality that can't be cashed out in possible-worlds-considered-as-counterfactual.

    [–]tristanhaze[S] 1 point 2 days ago
    Thanks for the comment! You touch on a delicate point. I would say that, with this sort of discourse with what can happen in chess for example, there may be a one-to-one correspondence between possibilities considered as actual, and possibilities considered as counterfactual. So the 'if and only if' may indeed hold in this case. But that doesn't mean the correspondence cannot break down in other sorts of cases, and it doesn't mean that what's on the right side of your 'if and only if' counts as a good analysis of what the left side means.

    I hope that helps. I don't mean to say that these matters are easy or that I have clarified them to my satisfaction. I do think that we can clarify two conceptions here which are at least prima facie non-identical, but I probably can't at this point give you a satisfactory argument for the thesis that subjunctive modality can't in the end, non-obviously, account for the metaphysical modality conceived in the broader way. (I'm inclined to think that it's best to go the other way round, in a sense, and believe I have a satisfactory account of that sort - which I just alluded to in the post but will post on at greater length soon - but I haven't yet hit on any reason to give for this other than 'Then my account would work and, furthermore, not be circular', but that reason is perhaps not as bad as it sounds. Maybe in the end I should just maintain my account, but allow that it is circular, or to use a less pejorative term, recursive. I don't know.)

    But thanks for nudging me further toward trying to sort that out. I'm working on it!

  5. [–]Random_dg 2 points 3 days ago
    I wonder about this part: "producible by the language system to which the proposition in question belongs". Why should the proposition be analyzed only relative to one language system? What is a language system?

    [–]tristanhaze[S] 1 point 2 days ago
    Yes, this is quite a large moving part of my account. In the first instance, I have to plead that I was only alluding here to an account which I will post on at greater length here.

    For now, a look at my post 'Propositions: A Neo-Wittgensteinian Approach' may help indicate what my thinking is here.

    Again, I will have more to say on this in future, but I will say that my idea of a language system is not meant to be anything unexpected, or overly recherche or technical. It's one of my basic ideas, and I see it in the mid-period Wittgenstein (which may be no comfort to you of course!). I'm not saying it can't be problematized or that there aren't important clarifications to make with it, but the starting point is the very basic idea that propositions are linguistic items, and language is systematic. There are certain patterns in linguistic phenomena which we can get a handle of by thinking and talking of a system of language. We can talk about the roles expressions play in language.

    Take slips of the tongue, for example, where a wrong word or expression is used. They can be understood as cases where a word or expression is wrongly put in a place or role which actually belongs to another one. The existence of these roles shows the systematicity of language.

    Hope that helps at least a bit. Thanks for your interest, and look out for my forthcoming post on the account I'm alluding to here! (It won't be my next post, but it won't be too long.)

  6. [–]section3 2 points 3 days ago
    Im going to echo /u/mvalenteleite here I also do not understand the difference between the two concepts broad vs narrow metaphysical modality, could you give another example and clarify?

    "The other concept, which I will call the concept of metaphysical modality in the broad sense, doesn't involve this contrast. It may be roughly characterized as modality which is neither epistemic nor somehow conventional. Modal facts which are the way they are irrespective of anything to do with our knowledge, and irrespective of any conventions we might have, are metaphysical modal fact"

    I don't see how the modality of the H is P is epistemically or conventionally dependent.

    [–]tristanhaze[S] 0 points 2 days ago
    Thanks for reading. Not sure if I can help much with this at this point, except to clarify that I don't maintain that 'Hesperus is Phosphorus' is epistemically or conventionally necessary. I think a more careful reading should bear this out. Thanks again.

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