Sunday, July 23, 2006

Modal Quasi-Realism

In his paper 'Morals and Modals', Simon Blackburn extends his quasi-realism into the realm of modality, apparently inviting us to simply identify possibility with ideal conceivability:
The context here is that Craig had demonstrated decisively the imaginative block that faces us when we try to conceive, in proper detail, of a counterarithmetical reality. The projectivist is then poised to see this imaginative block as something expressed when we insist upon the necessity of arithmetic. But Wright commented, 'If as Craig makes plausible, we are unable to conceive of how any alternative determination might be viable, then that is how things are with us; it is a further, tendentious step to inflate our imaginative limitations into a metaphysical discovery'. And Craig, acknowledging that he and Wright agree that we should not ask the imagination to do too much, concedes immediately: 'It certainly is a further step'. Is it so clear that there is a further step? Only if claims of necessity are 'metaphysical discoveries', and this the projectivist will query. (Essays in Quasi-Realism, p.60)

He clarifies this by analogy to his meta-ethical position (p.70):
We do not find it trivial to cross from a sentiment to a moral judgment. Only certain sentiments -- those of a certain strength, or with certain objects, or those accompanied by sentiments about others who do not share them -- form a jumping-off point. We are also conscious that there are doubtless flaws and failures in our sentiments, which are perhaps capable of explanation in the same way that we explain the defects of those who are worse than ourselves. But when the sentiments are strong and nothing on the cards explains them by the presence of defects, we go ahead and moralize. We may be aware that our opinion is fallible, but that is because we can do something with the thought of an improved perspective, even when we are fairly certain that one will not be found, and here as elsewhere commitment can coexist with knowledge that we may be wrong. The 'step' from a fully integrated sentiment of sufficient strength to the moral expression now becomes no step at all: the moral is just the vocabulary in which to express that state. Avoiding it would not be an exercise in modesty, but an impoverishing idiosyncracy of expression.

Why should it not be like this with logical necessity? We have arrived at the residual class of propositions of whose truth we can make nothing. We cannot see our failure to make anything of them as the result of a contingent limitation in our own experience, nor of a misapprehension making us think that their truth should be open to display in a way in which it need not be. We express ourselves by saying that they cannot be true -- that their negations are necessary. There is the bare possibility of being shown wrong -- perhaps our search into the causes of our imaginative block was inadequate, or perhaps we were under a misapprehension of what it might be for the proposition to be true. We may be uncomfortably aware of even great philosophers who mistakenly projected what turned out to be rectifiable limitations of imagination -- the a priori has a bad history. But as Wright notices, we should have no wish to make ourselves infallible when deeming things a priori. We make the commitment in light of the best we can do. There is no step, and no illusion.

Yet I think I can make something of the idea that ideal conceivability and metaphysical possibility might come apart. Talk of how the world could have been, and talk of what can be coherently imagined (with idealized cognitive powers), are not obviously synonymous. There's plausibly a link of sorts: we typically take conceivability as at least a guide to possibility. There may even be a perfect coincidence between them, so that all and only logical possibilities are ideally conceivable. But does that really mean that apriority and necessity are one and the same thing? Or can we somehow separate them, even without any metaphysical divergence that we can latch on to? (Might there be a sense in which one holds "in virtue of" the other, for instance? Or are they the same thing just under different "modes of presentation"? How else might we make sense of this?)



  1. If something is "ideally inconceivable" is that not because it is impossible?
    But I can imagine a situation where something might be possible but not conceivable... i.e. ideally conceivable things are a sub set of possible things (unless ideal conceivability still permits some sort of "error"?)

  2. Yeah, that asymmetry sounds plausible. Presumably if we can rule something out apriori then it really must be false. But being unable to rule it out (hence leaving it negatively "conceivable") doesn't obviously guarantee genuine possibility.

  3. I think you might want to revise the limits of conceivability: they are broader than you seem to allow. You say that all and only logical possibilities are ideally conceivable, but it seems to me more than that must be ideally conceivable. For example, it is not logically possible for arbitrary A to imply arbitrary B. That would lead to complete triviality, something that cannot be countenanced by any reasonable logic. However, we can conceive of a world where the laws of logic are different and triviality ensues. In this world the sun rises and it does not, grass is green and it is not, etc... It seems that conceivability must be broader in scope than logical possibility.

  4. "we can conceive of a world where... the sun rises and it does not"

    Can we? You might stipulate that the sun both rises and doesn't, but that isn't a stipulation that I can make any sense of. I certainly can't imagine any scenario which would be truly described by such contradictions. (You might try to build the contradiction explicitly into the scenario's specification, but then I simply can't begin to imagine it at all!) Plausibly, we can know a priori that such proposals are false, and hence they are "inconceivable" (as I use the term).

  5. Hmmm, I guess I'm not clear on why that situation is inconceivable. It seems easily conceivable to me. I can describe the situation as follows:

    It was morning in the alternate world of trivialia. The sun rose gently over the hillside. The lambs frolicked through the tall grass and basked in the first rays of sunlight. From her bedroom window nearby, Lily gazed across the countryside. She glanced at her watch, noticing that it was past 6:30 and wondered to herself why the sun hadn't yet risen..."

    I see nothing untoward about this situation. When you say that this is inconceivable, what exactly are you claiming?

  6. Yeah, I should take care not to equivocate here. I often use "inconceivable" in a technical sense as a synonym for "conceptually impossible", or something we can know to be false a priori. But in the present context, I think Blackburn is using the term more intuitively, to apply to those claims "of whose truth we can make nothing".

    I think both apply to your story though. I can't make sense of it (unless Lily simply has a false belief, or else is located in a different place where the sun is yet to rise, or some other non-contradictory explanation, but I take it you don't mean to take such an easy route out). At Lily's location at 6:30 (or whenever), has the sun risen or not? I take it the answer in your scenario is meant to be "both!" (and determinately both, not vaguely somewhere in between). But that's not an answer I can make any sense of. (Can you?) It also seems to be one we can rule out apriori as impossible.

  7. Yes, your interpretation of the story is correct, that is exactly the scenario I was trying to describe. I guess I want to say I can make sense of it, but I do realize that most people would object. Let me try to clarify the issue a bit and see where that gets us. When you say you find that you cannot make sense of the scenario, I take it that you are saying something like "this description expresses nothing coherent, it is meaningless babble". Is that about right?

    On a different point, forget about trivial worlds or contradictory worlds. Let me get back to my original point. Suppose, for the sake of argument, that classical logic is the correct model of good inference. Nonetheless, we have other theories of logic, like the intuitionist. These theories disagree in that the classicist says LEM is a logical validity, while the intuitionist says that it is not. My original point a few posts back was that, granting the hypothesis that (say) classical logic is correct, we can still conceive of what things would be like if intuitionist logic were correct. We can imagine a world where LEM fails and describe what is is like. This is logically impossible (given what we have assumed for the sake of argument) but it is conceivable. So conceivablility is broader in scope than logical possibility.

    Maybe my choice of examples (trivial logical worlds) was a poor example to motivate this point.

  8. "meaningless babble" may be too harsh, since at least the components make sense in isolation. It's just that they don't fit together to form a coherent or comprehensible whole. Kind of like "colourless green ideas sleep furiously", and all that.

    On your other point, I'm not so sure that logic is a component of reality. I can picture a scenario, and describe it in logical terms. If talking to an intuitionist that might restrain my vocabulary in certain respects. But how does changing your logical framework make the picture look any different? I take truth and logic to be semantical rather than metaphysical, so that a 'true contradiction' is really just a bad description.

  9. I don't really see how it changes the debate if you take logic to be arbitrary, conventional, non-objective or however you prefer to characterize it. This would be parallel to the moral quasi-realist who takes ethics to be conventional, yet categorical. Everyone has different sentiment, so different ethical principles, but from my standpoint the ethical principles I adhere to are the correct ones. And there is no sensible way for me to express that they are not.

    However, there is a sensible way for me to express the subjunctive claim "if pain were good, then torture would be permissible" or some such thing. Even though I know full well that the consequent is false, I can recognize the conditional as true because it follows from the counterfactual condition described.

    Similarly so with logic. I adhere to some set of discursive practices, which includes a component of correct inference. If you want to characterize this "meta-logically" as conventional or quasi-realist that is perfectly fine. But either way, it is categorical and there is no way for me to make sense of alternate rules of logical inference actually holding true.

    However, as before, there is perfect sense to be made of the subjective claim "if intuitionism were the correct logic, then some instances of LEM would fail". Doesn't that seem right? Hence, to return to my main point, doesn't conceivability outstrip logical possibility?

  10. What is considered conceivable or not
    varies among folk.
    And what follows from conceivability
    differs among folk.
    Sky-blue-pink is or is not conceivable.
    1 plus 1 is 3 is or is not conceivable.

    What can you say? They have definitions of conceivable which are incommensurable? They exclude from their definitions examples the other includes?

    Or. one group makes sense while the other spouts nonsense-- well, then we can
    argue over the correct definition of nonsense.

    Why not just say that under one set of definitions of terms we can conclude this and under other definitions of the terms we can conclude that.

    Or Why not just say such and such set of definitions suits one group's purposes and intuitions but not the other group's.
    I haven't been convinced that there is a hierarchy starting with unreal and ascending to real, that is independent of people's varying intuitions and I don't find it a necessity to make the aim of philosophy a search for the one point of view which should be awarded the spot at the top of the heap.

    One will often be swayed more by one point of view than by another. So what? I find no necessity
    to establish a claim to the universality of one point of view over others or one set of arguments over others.
    I do however believe in truth. Individual truth exists I think.
    I think philosophy would be more interesting if we abandoned not truth, or the idea of most useful thought, but the notion of highest, or universal truth. Even the most solid scientific facts are subject to recasting and to ambiguity of interpretation, and mathematical description of the world is possible only when the world described is narrowed to the few elements conducive to quantification.
    Life is so much broader and it is worth celebrating in its broadness.


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