Sunday, May 04, 2008

Ontological Reduction

Is consciousness ontologically irreducible? Richard Brown thinks that the question is incoherent:
What [the identity theorist] says is that there is only ONE thing there, the brain and its various states, and you cannot reduce something to itself!

He goes on to contrast this with linguistic, theoretical reductions, and explains how those are irrelevant to the debate between physicalists and dualists. I agree with that part. But I think he's wrong to think that linguistic reductions are the only coherent form of reduction.

We can see this because, as I've been saying all along, the question is whether qualia are reducible in the same sense that tables and chairs are, whatever that may be. Now, it's an open question whether our talk of tables and chairs could be replaced by (perhaps complicated and long-winded) talk purely in the language of microphysical theory. But we don't care about talk. What matters is that the facts about tables are obviously settled by the microphysical facts. If you have a coarse-grained conception of 'facts', maybe they are even one and the same fact. Even so, we can get to a metaphysical notion of reduction by appeal to the truthmakers for our sentences. Regardless of whether table talk is linguistically replaceable by particle talk, there's no question that the microphysical facts are what make our table statements true (if they are true).

Once you've included the microphysical facts in your base facts, you do not need to add any further 'table facts' in addition. Those are already covered. It is in this sense that table facts are reducible to physical facts. And it is in this sense that the question of physicalism comes down to the question whether qualia are reducible. It is simply the question whether we need to add phenomenal facts to our fundamental base facts, or whether they "come along for free" (like tables do) given the physical facts P.

(I find it convenient to use the term 'reducible' to invoke this idea, but you're of course free to pick another word if you prefer. What's not helpful is to simply insist, "the debate between the dualist and the materialist is in no way a debate about reduction", and so ignore my underlying idea concerning what the debate is about. RB wanted to focus on what counts as 'physical' or 'non-physical', but that soon degrades into semantics. The substantive issue, as I see things, is whether we must include qualia as an additional primitive among the base facts. This understanding makes it clear why RB's "non-physical zombie" parody argument falls flat (to put it mildly). See my 'Zombie Review' for more detail.)


  1. What [the identity theorist] says is that there is only ONE thing there, the brain and its various states, and you cannot reduce something to itself!

    I didn't finish the post, so maybe this was said. I just don't see the incoherence. The idea is the same for informative identity statements. Discovering that Hesperus = Phosphorus--that there are not two things, but one--is pretty much the same as discovering that there are not two events--a mental event and a physical event (or two sorts of events)--but one. What gets reduced are the mental events: evidently, those things do not wear their material nature on their sleeves.

  2. "It is simply the question whether we need to add phenomenal facts to our fundamental base facts, or whether they "come along for free" (like tables do) given the physical facts P."

    It seems to me that the 'phenomenal facts' might be the 'fundamental base facts' because the 'fundamental base facts' would include the 'phenomenal facts' and vice versa. In what sense would you 'build up' the facts and not the other way around? mightn't they be corollaries?

    For example, Wittgenstein might argue that language is the fundamental fact (whatever 'language' might be - I propose 'Value-full interaction') of 'us' and that the biology only needs to be sufficient. The qualia comes from the phenomena of language. Moreover, I think W. would have to say that the phenomena of language is grounded in the biology (it wasn't handed down from God afterall). So either, or, the two (language>qualia vs physical qualia>language) seem to meet in the middle of a semantic nightmare.

    To say that A+B+C...=Z and that A,B,C are the 'fundamental facts' is silly, because why is Z not the fundamental fact? The only way I think one could say this is by admitting Cartesian-ism and therefore A+B+C... ->Z just like how the mind faces the world but is independent from it.

    But, 'being-in-the-world', so to say, seems to conclude that the two are corollaries. This 'I-ness' seems to be in development and doesn't seem to necessarily have biological or physical 'foundation' independent from a linguastic foundation, nor that the linguistic foundation is independent from the physical foundation.

  3. No micro- or macro-physical facts can serve as truth-makers for the fact that chairs are for sitting on, though micro-physical facts will of course account for how the nature of chairs makes such facts about them possible. And since there are normative facts about all physical entities, there is already a clear problem of physical reduction (particularly since, arguably, there are no such things as chairs without the normative facts). This makes me wonder why there would need to be a different kind of irreducibility when it comes to qualia. When we state all the physical facts about chairs, we've stated all the physical facts about an entity to which we have a particular kind of relationship. Why can't we give the same sort of analysis for seeing red or feeling pain?

  4. Roman - those sorts of normative facts surely globally supervene on physical facts. Chairs are for sitting on in virtue of the facts about their use and origin. There is no "chair zombie" world that is physically identical to ours but lacking chairs. So, once we settle the underlying physical facts, these normative facts will come along for free.

    See also section 4 of Chalmers and Jackson's 'Conceptual Analysis and Reductive Explanation' [pdf].

    Erik - "To say that A+B+C...=Z and that A,B,C are the 'fundamental facts' is silly, because why is Z not the fundamental fact?"

    Very interesting question! I don't think it's "silly", though, to think that some facts hold in virtue of others, and not vice versa. For example, Bob is a bachelor in virtue of being an unmarried male; it seems clear in this case that 'unmarried' and 'male' are more fundamental properties than 'bachelorhood'. (Though I'm sure they can in turn be reduced to even more fundamental, physical properties.) That's not an answer to your question, I admit. But I think it shows that we should expect there to be some answer, even if we cannot immediately say what it is.

  5. We get inferences to reduction even when we're not certain that our reductionist model accounts for every pre-reduction fact. For example, there are some complex systems of water that have not been simulated in terms of H2O molecules because the computational task is beyond our abilities. So it is possible that, say, some kinds of whirlpools cannot be accounted for in terms of H2O. Perhaps such whirlpools require some sort of irreducible water spirit? Yet, we don't doubt that water reduces to H2O. Why?

    The argument is roughly like this: irreducible water spirits don't place constraints on experimental tests (while still being relevant to them), whereas physical reductionism does. Experimental results are consistent with the constraints when they needn't have been. Therefore, it is probable that water reduces to H2O.

    Suppose there are fair coins and two-headed coins, and I take one of the coins at random and flip it in front of you. It lands heads. What are the odds that the coin is fair? Clearly, it is more likely that the coin is the two-headed coin. Now take this to the Nth power, and you'll see why we don't regard water as consisting of water spirits (fair coins), even if we have not formally reduced every instance of water behavior we have ever observed.

    Similarly, there are a great many ways that minds are consistent with physics in ways they needn't have been if minds were not reducible to physics. Hence, it is rational to believe that minds are likely to be physical systems (they might be irreducible, but it is terrifically unlikely because we would be supposing that very special, fine-tuned form of irreducibility that looks just like reducibility wherever we look).

    So I agree with you, Richard. I think the dualism argument is most definitely about reduction.

    As for the zombie argument, I personally think there's some very subtle question-begging going on. In order for qualia to escape the aforementioned reductionist inference, it has to be claimed that qualia are wholly irrelevant and disconnected with physics. This means it is also implicitly claimed that qualia cannot have a physical explanation. If this assumption is sustained, then qualia don't have any implementation, so physical minds don't place any more constraints on experiment than do irreducible ones, and the inference to reduction to physical minds fails. But if we deny from the start that qualia can have a physical explanation, that's begging the question.

  6. Hi Richard, thanks for the interesting post!

    I have a full response up over at Philosophy Sucks here...but here is the jist.

    I am happy to agree that this is the real issue (though I wouldn't call it an issue about reduction). But now that we all agree on what the issue is, it should be even more obvious that the zombie argument begs the question against the materialist. They tell us to conceive of a world where there are physical duplicates of us that lack consciousness and that doing so shows that the qualitative facts do not ‘”come along for free” (like tables do) given the physical facts P’. But how do you know that you are really conceiving that world without contradiction? If materialism is true then you are not really conceiving what you think that you are. Since we do not know if materialism is true or not we do not know if we are really conceiving the zombie world without contradiction or not. And that is the point. Without knowing whether or not materialism is true we cannot know if the zombie argument is a good argument or a question begging argument.


    The idea was that if there is really only one this there, then it deson't make sense to talk of reduction in the ontological sense. How could one thing be reduced to itself?

  7. ooppss...that supposed to be 'one thing there'...and I just noticed the end of Doctor Logic's comment, which captures roughly the same point I have been trying to make...

  8. DB - I think you misrepresent the zombie argument, at least compared to the version offered in my 'Zombie Review'. Representation skepticism about what we're conceiving is a red herring, and easily avoided. The central premise of my argument is instead that (P & not-Q) can't be ruled out a priori. (The zombie intuition then supports this premise.) I don't see why you'd need to know whether materialism is true prior to assessing this premise. Though if you accept the other premises of the argument in addition, then resolving this might (subsequently) serve to resolve whether materialism is true. Such is the nature of a valid argument.

    For more on the 'question begging' charge, see my post 'Thought Experiments and Begging Questions'.

  9. The root philosophical disagreement is this: you seem to assume that you can give a complete physical description of a world, leaving out normative facts, and get those facts for free in the bargain. That's quite a deal, of course, if you completely leave out the role of normative facts in any physical description. But it seems hugely dubious that we can give any complete physical description without employing any normative facts. That requires a naive realism, where the physical world magically has rational properties, and human rationality has the role of sorting those out.

    "Physical reality" is itself part and parcel of a particular way of conceptually breaking up the world. And we understand it by using principles of inductive and deductive logic. Now you can say that those principles are just a function of the way our brains are physically made up. But it will remain the case that you have no hope of figuring out how our brains are made up without employing those principles. The physical world as we conceive it is a product of, among other things, our normative capacities. So taking those capacities in turn to simply be free byproducts of the physical world is misleading. The "world" on which those capacities supervene is not the same "world" that we understand through those capacities, for the simple reason that the former is unarticulated.

  10. "Very interesting question! I don't think it's "silly", though, to think that some facts hold in virtue of others, and not vice versa. For example, Bob is a bachelor in virtue of being an unmarried male; it seems clear in this case that 'unmarried' and 'male' are more fundamental properties than 'bachelorhood'."

    So what you propose is something like this:

    Given a, b, c,… etc, x follows.
    (You might even have lemmas, like b, c yield d)

    I think Gödel’s first theorem disproves the possibility of this being able to be done in anything but the trivial example.
    “For any consistent formal, recursively enumerable theory that proves basic arithmetical truths, an arithmetical statement that is true, but not provable in the theory, can be constructed. That is, any effectively generated theory capable of expressing elementary arithmetic cannot be both consistent and complete.”
    It’s clear that the facts would not produce an inconsistent system, so to have a system that can be ‘boiled down’ to fundamental base facts (as mathematics has axioms) which can make statements based upon those facts, you must appeal to the system as a whole. The system will never be complete (if it were it would be inconstant), and therefore, I think, you would need to appeal to all possible facts
    So the ‘fundamental facts’ of x would be something as follows:
    Let {Z} be the set of all facts. x would be an element of this set. The ‘fundamental basic facts’ of x seem to be {Z}-{Z-x}=x. Even if we ‘grouped’ the elements of Z, it is not clear to me that 1) you wouldn’t have an infinite number of groupings and 2) that the groupings do anything but rename their respective elements. How can we talk about only part of everything? The part we leave out still affects the parts we leave in.


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