The following is obviously true:
- Any world that contains an exact duplicate of the solar system, over all its past, is a world that contains human-type mental states.
But now we see that Humeanism about laws plus naturalism about mind requires us to deny (1). For we could imagine a world with an exact duplicate of the solar system but where the behavior of stuff outside the solar system is so very different from how it is in our world, that the familiar sorts of laws that are crucial to our mental functioning being as it is do not hold, say, the Pauli exclusion principle is false, though by chance the local behavior in the solar system is as if those laws held, so in our solar system, fermions don't share a state. But without such laws we don't have the kinds of functional interconnections that are involved in human-type mental states.
I suppose the Humean might just deny (1). But now we can make it more ridiculous. On Humean views, what laws there are depends on the future course of the universe. Imagine that we have a universe which is just like ours up to tomorrow, but with an infinite future a day later, where everything goes topsy-turvy. None of the regularities that held up to tomorrow are global regularities, and a fortiori none of them are laws. Therefore, in that world, too, there haven't been any human-type mental states. And that's really absurd. For it means that whether there have been human-type mental states depends on how things will be from the day after tomorrow.
14 comments:
Sweet point, Alex--at least against naturalists of the functionalist variety. What will you say to the following 'localizing' reply? Not just any arrangement of matter that plays a certain role is a human-type mental event, but only an arrangement that plays the role in a certain place or at a certain time. That would allow them to preserve the view that human-type mental states--at least around these parts--are such and such arrangements of matter. I know the reply seems very ad hoc reply. But it parallels a familiar reply to multiple realizability concerns with functionalism; i.e., maybe there is more than one arrangement of matter that can play the role in different possible worlds, but in our region of logical space it is some particular arrangement of matter between our ears. Because of this similarity, I would expect it to come up.
But surely there have to be some nomic or causal aspects to the "role".
Imagine someone whose matter jumps around just as ours does, but where the states that in us constitute pain don't cause the states that in us constitute aversion, though by chance the pain-like states are typically followed by aversion-like states, and so on. I don't think a naturalist would want to say that there pain there. But for typical Humeans, causation depends on laws.
Moreover, all the naturalist theories of content make use of causation.
Nice. Tim and I make a similar point in a forthcoming paper about action. Whether we are said to act at all, much less freely or not, depends on matters thousands of years in the future (say).
Lewis explicitly denies something like 1. He says that, while we might not have thought that whether we're in a certain mental state depends on matters external in that way, but it's a bullet the Humean has to bite. (Can't recall the place.)
The future directed version gives the humean a solution to the problem off induction. We think so the local regularities must be global laws.
If one is a naturalist of a stripe purported by Nagel in Mind & Cosmos (that includes non-materialist elements and organized by their respective laws [monistic elements and teleological laws]), then on that naturalism 1. can still be true and there can be a naturalism about mind. However, we must assume that Humeanism will apply only to laws that are relevant to the functional facts about matter. Those laws that are relevant to the funcational facts about mind would make a difference at the local level if they were altered. But Nagel's attempt at an altered naturalism is certainly controversial.
Paul:
Yeah, but I don't know if one can fit teleological laws into a Humean framework. Maybe somehow?
I don't think (1) is obviously true on the reading that's relevant here. Mental properties usually have a nomic and therefore modal dimension: whether something is a toothache depends on what it is /caused/ by, under what alternative conditions it /would/ arise, what kinds of behavioural /dispositions/ it gives rise to, and so on. Similarly for beliefs, desires, etc. These nomic features are plausibly tied to the laws of nature: if you vary the laws while holding an object's categorical properties fixed, the nomic features can vary. It follows that if a possible agent is a categorical duplicate of me, but in a world with very different laws, the agent's states will generally have different nomic profiles. The same is true if we look at categorical duplicates of the entire solar system in worlds with different laws. So (1) is false.
The future version seems stronger to me. It seems really weird to think that there now being consciousness depends on what will happen next year.
I agree that the Humean position is slightly peculiar here, but again I don't think it is so bad. I suppose the kind of dependence you have in mind is epistemic (for counterfactual dependence, we could tinker with the closeness relation to block or limit the result). The hypothesis under consideration is a counterinductive scenario in which the regularities we have seen so far are mere flukes. On this supposition, our nomic beliefs are thoroughly mistaken: what we take to be the laws are not laws at all, etc. In particular, we are thoroughly mistaken about the nomic profiles of (what we take to be) our mental states. But then we are mistaken about the nature of these states: whether they are toothaches or beliefs etc.
I'm thinking more of grounding dependence here.
There will also be counterfactual dependence coming from entailment of the following sort: the history of the world up to now conjoined with certain future states entails that nobody had any mental states.
All that said, isn't it weird that there be such a strong solution to the problem if induction: if many present regularities peter out, we're not conscious; but possibly we're conscious; so etc.?
Wouldn't the regularities have to peter out in a rather specific way in order for us not to be conscious? So at most we'd get an argument against some specific counterinductive scenarios, assuming facts about consciousness. In any case, isn't our conception of ourselves as conscious subjects, perceivers, deliberators, agents, etc. really tied to assumptions about our nomic features? On the skeptical supposition that the nomic facts are utterly different from how we think they are, is it really clear that we are properly described as "conscious", as "agents", as "perceiving", etc.? Perhaps these expressions don't have clear application conditions any more in such a scenario.
Another response a Humean could make to the kinds of worries you raise is to allow for local "laws" in the characterisation of mental profiles, based on regularities within a relevant region of spacetime. In the kind of scenario you describe, where the past is very orderly but the future a mess, perhaps the best thing to say is that there were laws in the past, but no longer in the future. These local laws are enough to secure our mental states.
1. It seems to me that we can tell that we're conscious rather than conscious*. It's my Cartesian streak. :-)
2. I think we can identify specific regularities that need to be nomic in order for us to be conscious if naturalism is true. One candidate is the Pauli exclusion principle. Without it, we just don't have the kind of chemical causation that seems crucial to the functioning of the brain. So it seems that we should be able to rule out futures in which Pauli exclusion completely breaks down.
3. The point about how local laws might be the best there is is a good one. It does complicate the counterfactual scenarios. But if there is an infinite and sufficiently messy future, we shouldn't be surprised by even longer streaks of even better law-candidates.
check out Jaegwon Kim's paper "The Myth of Non-Reductive Materialism." If I am remembering rightly, he makes the same basic point with respect to a particular supervenience claim about the mental and the physical.
I don't see the same point there.
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