Monday, March 24, 2008

Arguing with Eliezer: Part I

I had the pleasure yesterday of meeting Carl Shulman and Eliezer Yudkowsky (of Overcoming Bias fame) while they were in town, and hashing out some of our philosophical disagreements. It was interesting, because they're both very smart, and Eliezer's starkly materialist/reductionist ideology was shared by my past self. So I'm not entirely unsympathetic. But it was also frustrating in some respects, since he seemed to assume that any disagreement was simply due to a failure to appreciate his basic arguments, rather than a considered judgment that they aren't wholly compelling. So let me discuss a couple of issues in more detail, and attempt to lay out some of the reasons why I've shifted away from his blanket reductionism over the years.

(A) Fundamental Normativity. Eliezer holds that normative terms (e.g. 'should') are reducible to a particular framework of assessment -- roughly, the ultimate norms endorsed by the speaker. He calls this 'objective subjectivism', and it bears some similarity to the 'Objective Moral Relativism' I endorsed back in 2005.

I now find this unsatisfying, for several reasons. (1) The most obvious is that there's nothing really normative here, in the sense of an ideal that potentially outstrips any purely descriptive facts (incl. my current preferences and accepted norms). Though Eliezer wouldn't like to admit it, this is less a reduction than an elimination. Anti-realist maneuvers can save many of the appearances of normative practice, but its deepest aspirations are ultimately rejected. (2) His view implies that many normative disagreements are simply terminological; different people mean different things by the term 'ought', so they're simply talking past each other. This is a popular stance to take, especially among non-philosophers, but it is terribly superficial. See my 'Is Normativity Just Semantics?' for more detail. (3) We can go beyond the impoverished instrumental conception of rationality on which this view depends. Ultimate ends may themselves be assessed as more or less irrational. (I first realized this here.)

(B) Fundamental Mentality. My post on 'Dualist Explanations' outlines the case for property dualism, and defuses typical worries of the scientifically minded. Now, Eliezer seems to think that the causal inefficacy of non-physical phenomenal properties ("irreducible consciousness") is a knock-down argument against them. I once agreed, but again, have since changed my mind. My post, 'Why do you think you're conscious?' addresses this challenge in some detail.

There are some bullets to bite either way. I admit it's a bit odd to think that the words I type are not causally related to the facts I purport to describe. (That's an extreme way of putting it; do follow my above link to put this in perspective.) But, upon reflection, I find this commitment less absurd than denying the manifest reality of first-personal conscious experience (as reductive materialists like Dennett and Eliezer do), or engaging in the metaphysical contortions that non-reductive materialists must (see my 'dualist explanations' post).

(C) Epistemology. Eliezer writes:
When "pure thought" tells you that 1 + 1 = 2, "independently of any experience or observation", you are, in effect, observing your own brain as evidence.

I responded:
It's just fundamentally mistaken to conflate reasoning with "observing your own brain as evidence". For one thing, no amount of mere observation will suffice to bring us to a conclusion, as Lewis Carroll's tortoise taught us. Further, it mistakes content and vehicle. When I judge that p, and subsequently infer q, the basis for my inference is simply p - the proposition itself - and not the psychological fact that I judge that p. I could infer some things from the latter fact too, of course, but that's a very different matter.

In discussion, Eliezer emphasized the demands of (what I call) 'meta-coherence' between our first-order and higher-order beliefs. If you reason from p to q, but further believe that your reasoning in this instance was faulty or unreliable, then this should undermine your belief in q. I agree that reasoning presupposes that one's thought processes are reliable, and a subjectively convincing line of thought may be undermined by showing that the thinker was rationally incapacitated at the time (due to a deceptive drug, say). But presuppositions are not premises. So it simply doesn't follow that the following are equally good arguments:
(1) P, therefore Q
(2) If I were to think about it, I would conclude that Q. Therefore Q.

(Related issues are raised in my post on 'Meta-Evidence'. See also my argument for the inescapability of a priori justification.)

Concluding Remarks. Oops, this is too long already -- I've shifted my concluding thoughts to a new post.


  1. Wait a sec.

    But, upon reflection, I find this commitment less absurd than denying the manifest reality of first-personal conscious experience (as reductive materialists like Dennett and Eliezer do), or engaging in the metaphysical contortions that non-reductive materialists must (see my 'dualist explanations' post).

    Why does reduction amount to elimination here? Can't you be a reductive materialist and still accept that there's such a thing as first-person experience? You might, for example, hold that the arrangement of particles in spacetime that constitutes a brain is also what constitutes first-person experience.

    Perhaps this is the same idea as your psycho-physical bridging laws. But, I confess, I don't see why psycho-physical bridging laws aren't a reduction. Why not call them "physical bridging laws?"

  2. Paul, we're talking here about analytical reductions, i.e. thinking that 'conscious experience' just means 'whatever fills such-and-such functional role', such that zombies are logically impossible (self-contradictory).

    Psycho-physical bridging laws are contingent -- the laws could have been different, in which case the material stuff would have failed to give rise to consciousness, which shows that the material stuff does not strictly suffice for consciousness.

    See the comments here for further clarification on this matter.

    (I do agree that property dualism offers all the "reduction" that any scientist could ask for, since they're merely concerned with nomological possibilities anyway. That's a major theme of my 'dualist explanations' post.)

  3. Oh, I see now. I hadn't fully understood that claim until reading the Kripke post.

    Having done so, I agree with you... it seems trivially true that you can't analytically reduce first-person conscious experience in that sense.

    But now I wonder why anyone, apart, that is, from those who really care about the difference between nomological necessity and metaphysical necessity, should care about whether conscious states are analytically reducible to physical properties of brains. (Admittedly, that group of people includes a lot of really important and smart philosophers.) What, that is, does this kind of property dualism commit one to? If nothing (i.e. if you're right that the scientists can be satisfied by the ... what should we call it, contingent reduction?), then, really, who cares? I mean, there are possible worlds where my left toenail is god...

  4. (On the Kripke post, incidentally, I'm skeptical about zombie world as a refutation of physicalism. Why can't you have a version of physicalism that counts natural laws as part of -- well, of the physical to which physicalism refers? Otherwise, do you even need zombie world to refute physicalism? Why not just a world that is otherwise identical except that some constant in some physics equation is different?)

  5. Hmmm - I seem to disagree with you and agree with Eliezer on all these same points. Maybe we can rehash them again when I visit Princeton April 14?

  6. Paul - right, we might say the interest is "merely" philosophical. That is, it's only interesting insofar as we care about the fundamental nature of reality, and whether material stuff strictly suffices for consciousness. (Of course, that seems plenty interesting to me! But it has no implications for empirical predictions, etc., so if that were all one cared about...)

    "Why can't you have a version of physicalism that counts natural laws as part..."

    Well, you could, but it needlessly obscures that portion of logical space that would have us posit non-physical natural laws. But names aren't important. What matters is the substantial dispute between those like Chalmers who think that zombie worlds are possible -- so that we require psycho-physical bridging laws in addition to those that emerge from the study of physics -- and the many others who deny this. The real point is that there's nothing in the equations of physics that entails the existence of first-personal consciousness. A scientifically omniscient A.I. would expect to find me typing these words, of course. But it wouldn't expect that there was really any first-personal experience behind them. (It wouldn't even have the concept, unless it were conscious itself, as explained in my 'why do you think...' post.)

    Robin - I look forward to it!

  7. Richard: I think we agree on everything, except that I think our shared conclusion amounts to "Eliezer is right," and you think it amounts to "Eliezer is wrong." Because it seems like for any purpose other than the most narrow and specialized philosophical ones, the utterance "conscious states are physical states" is unproblematically true. It's only when we get into wacky modal land that it becomes false. But those of us who like to spend time in wacky modal land ought not to muddle up perfectly workable scientific conclusions. And almost all discussions of the matter can be conducted way out of wacky modal land.

    Likewise, nobody other than a philosopher would think property dualism is different from simple materialism. In 99 out of 100 cases, an argument against dualism is targeted against substance dualism. And the reason is that nobody other than a philosopher has reason to care about the difference between property dualism and simple materialism, or whether there's type-identity or just token-identity between mental and physical events. What non-philosophers tend to care about is stuff like whether there's a soul.

    So in any discussion between two non-philosophers, the simple utterance "dualism is false" refers to substance dualism, and is thus true as true can get.

    (As for their being nothing in the equations of physics that entails the existence of first-personal consciousness, why couldn't those psycho-physical bridging laws count as being in the equations of physics?)

  8. Paul, like I said, I agree with 99% of the things Eliezer says to non-philosophers. What I disagree with are the things he says to me, e.g. that zombies are inconceivable.

    P.S. I'm using 'physics' to describe the scientific discipline, which is essentially limited to the study of third-personal phenomena (causal structural relations, etc.). Again, you could co-opt the term to mean "our best science supplemented by our best philosophy". But that would be needlessly misleading. Better to use the broader term 'natural' to cover this larger territory.

  9. I think my beef is with the way you frame it. In the follow-up post, you treat this as an example of a case where an intelligent non-philosopher, unaware of the strongest arguments against his position, makes arguments that are technically incorrect -- that are fine when dealing with ordinary folks, but that don't fly when dealing with philosophers because of that technical incorrectness.

    But I think that's a misguided way of thinking about it. The issue isn't that Eliezer is making arguments that are technically incorrect because he's used to arguing against the folk. He's making correct arguments about different questions. When he says "[substance] dualism is false," he doesn't mean the [negation of the] same thing as when you say "[property] dualism is true." And his arguments aren't even technically incorrect in the context in which they're raised.

    But now I'm putting thoughts into his head as well as words into your conversation, which is no doubt totally unwarranted. Maybe your conversation really was about property dualism rather than (as I suspect) property dualism on one side and substance dualism on the other, or something of that ilk. In which case, consider this whole comment withdrawn.

  10. No, like I said, we were explicitly discussing the substantive issues (e.g. conceivability of zombies), not the superficial question whether the sentence "dualism is false" is true. So I stand by my framing, though I would put it even more strongly than you do. His arguments are not merely "technically incorrect". They are overgeneralized (from his folk interactions) in a way that leads him to make serious philosophical errors.

  11. Fair enough! That's what I get for trying to read minds. :-)


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