The Reverse-Knowledge Argument

I was thinking about my reverse-zombie argument from zoombies and shombies today when I suddenly remembered a remark that Chalmers made somewhere to the effect that the knowledge argument, the zombie argument, and Kripke’s modal argument are all of apiece and all stand or fall together (I was thinking about this partly because I am working on another paper “Fool’s Pain: The Kripkean Response to Kripke’s Modal Argument against Physicalism”). It then occurred to me that if this is true and the reverse-zombie argument actually works then it should be possible to construct a reverse-knowledge argument. So, let me give it a try.

Consider Maria. Unlike Mary, Maria is not a super-scientist. She is a super-phenomenologist. Maria knows all of the qualitative facts about red. She knows what it is like for her to see red in such a way that she can discriminate between very fine shades, etc.  But like Mary, Maria was raised in a special room. This is not a black and white room, it is a science-free room. So, though Maria knows all of the qualitative facts about red she knows none of the phsyical facts. She is kept in total ignorance about physicial color theory. She has a masterful grasp of the qualitative facts but no grasp of the physical facts. Now let us suppose that Maria is let out of her room and taught color science. In particular let us suppose that Maria gets out of her room after we have a completed physical theory. She then learns all of the (complete) physical theory about the brain, the way it works, wavelengths, light recepters at the eys, the tranduction of signals, etc, etc. Won’t she have learned something new about red? The answer is yes; she will learn that her color experience is a physical event in her brain. Maria will leanr something that she would express by saying ‘oh, so that what my color experience is!’ In short she will leanr that all there are  are physical facts.


18 thoughts on “The Reverse-Knowledge Argument

  1. I like this argument; it makes quite clear that the ‘intuition’ involved in the knowledge argument is not unshakable. I don’t think it’s clear that she will learn that physical facts are all there are; rather, what she will learn is that all of her qualitative experiences have an adequate physical account. That is, her qualitative experiences, which have the status of facts for Maria, will now be not just facts but intelligible facts, explained facts, rather than basic-level facts. One of the additional supports that can be brought in favor of this way of looking at the problem is the fact that we have already on occasion found that what seemed to be basic-level facts (e.g., the solidity or structure of solid objects) could instead by explained in terms of more basic facts (e.g., physical forces); so, without a clear reason to think otherwise, it seems quite possible that our qualitative experiences could be explained in terms of more basic facts. It doesn’t prove anything (just as I don’t think the knowledge argument could prove anything); but it does show that there’s more structure to the problem than comes to the surface in the knowledge argument itself.

  2. still doesn’t prove that physical facts are explicitly “learnable.” I’m not sure if I think they are or not, however I don’t feel comfortable with the leap whereby, upon having science explained to her, Maria learns something. Take this counter example…

    On the assumption that “all the qualitative facts about red” is a real thing, and a knowable thing, and similarly about “all the quantitative facts about red” (I doubt both of these but run with me). What in the argument says that Maria won’t, upon having the physical facts explained to her, say “You guys have this totally wrong, let me explain…”

    The problem, to my mind, is that this argument shape relies on assuming those two totalities. “All the qualitative facts about red” and “all the quantitative facts about red” are unknowns. Without actually having one or both of those complete sets of knowledge, I don’t see how you can say that one will logically win. It seems to me to be a bit more of dressing up a personal preference to appear as an argument. The weight of this argument still lies in the existence of these two discrete quantities of knowledge, and the assumption that one is more convincing or that they are equally convincing.

  3. This isn’t supposed to be a tu quoque against people who think that the original knowledge argument is sound is it?

    If it is, then I’m not sure it would be successful. Here’s a simplified extraction of the original knowledge argument against physicalism.

    (1) If all facts are physical, then Mary doesn’t learn anything new.
    (2) Mary does learns something new.
    (C) Therefore, it’s not the case that all facts are physical.

    The parallel argument, I suppose, would be….
    (1) If all facts are qualitative, then Maria doesn’t learn anything new.
    (2) Maria does learn something new.
    (C) Therefore, it’s not the case that all facts are qualitative.

    A proponent who accepted the knowledge argument and went on to endorse dualism would be happy to accept the conclusion of the second argument. So, I don’t see the parallel argument forcing such a proponent into accepting something unpalatable. But maybe that wasn’t your intention.

  4. Hi everyone, sorry for the delay in responding. My internet at home went out for some reason and it juts cam back on today.


    Yeah I agree with your modified way of putting it. In the future I will emphasize that instead of the way I had it. Thanks.


    Yeah it is. The problem is I don’t think your arguments are exactly right. They should be like this.

    (1) If qualitative facts are reducible to, or deducible from, physical facts then May shouldn’t learn anything new
    (2) Mary learns something new
    (C) Therefore qualitative facts are not redicible to, or deducible from, physical facts

    The parrallell would then be

    (1r) If qualitative facts are not reducible to, or deducible from, physical facts Maria should not learn anything new
    (2r) Maria learns something new
    (Cr) Qualitative facts are reducible to, or deducible from, physical facts

    Dru, you said that you had the same worry as Andrew so I suppose this is a response to you as well…but it seemed to me that you were asking something different, but then maybe I misread your comment.

  5. looking over Andrew’s comment again, I might have misread it the first time around. Let me try to explain my quibble a bit better…

    There’s 2 things that bother me. The first is the amount of argumentative weight which lands on these quantities of “all the knowable quantitative/qualitative facts about X.” I don’t see a good reason to assume that there is such a thing. That is sort of a tangential objection though, so I’m not really interested in derailing the conversation for its sake. Maybe a good line of inquiry another time though.

    The second is more of an issue. I don’t see why, since someone outside the room can offer a different explanation which Mary doesn’t know yet, she necessarily learns something new. Well, more specifically, that she necessarily learns something new which is correct. This seems to me to be somewhat question-begging (based on your definition of question begging), in that it is only a true conclusion if you assume the description which opposes Mary’s is true and explains MORE than Mary’s explanation. This sword, however, cuts both ways, so I believe is more indicative of some sort of sketchy logical move rather than one side of this argument being weaker than the other.

    The strength of my second objection, however, rests on the first. We have no way of knowing if “everything qualitative/quantitative there is to know about X” is a real possibility, and therefore, no way of knowing whether what we CURRENTLY know either qualitatively or quantitatively might be better explained by a more complete theory of the opposite nature. Therefore, it seems to me that this argument shape (without the knowledge of these complete knowledge-sets) is question-begging. Either way you work it, the argument assumes that you learn something new from the other type of knowledge, which in turn relies on the concept that these complete knowledge-sets will share the trait of non-overlapping explanation that our currently incomplete models do.

    Now that I read Andrew’s comment more closely, I think it’s descriptive of our current state of affairs, but it doesn’t seem to directly imply my objection. I hope that clarifies a bit.

  6. I am not sure why you think that this is an objection to me though, since this is precisely my point! The knowledge argument is offered as an argument against physicalism, but it is clearly a question begging argument that assumes that mental qualitties are non-physical from the get go. So I agree that the Reverse-Knowledge argument is question beggining; it assumes that physicalism is true and so will only be plausible to those who already accept it. So the way you feel about the reverse-knowledge argument is the way I feel about the knowledge argument.

  7. RB argues:

    (1r) If qualitative facts are not reducible to, or deducible from, physical facts Maria should not learn anything new
    (2r) Maria learns something new
    (Cr) Qualitative facts are reducible to, or deducible from, physical facts

    But isn’t (1r) clearly false? If qualitative and physical facts are distinct and mutually irreducible, and Maria originally knows only the former, then obviously to expose her to the latter is to teach her something that she did not already know, i.e. something new.

  8. Looking back to the original post, I guess there’s meant to be an implicit “about red” appended to the premises (in a slight break from the original Mary argument, which holds without restriction). In that case, I should clarify that among the many new facts that Maria learns (according to dualism) is the fact that such-and-such brain states correlate with or give rise to her red experiences. So even with the restriction, (1r) still seems clearly false.

    The Mary argument arises because physicalists think that the physical facts exhaust the facts. There is no parallel to property dualism — it’s not as though anyone claims that the phenomenal facts exhaust the facts. Dualists think that there are physical and phenomenal facts, so knowing all there is to know about either one will still leave you with more to learn (i.e. about the other). This is the same asymmetry that explains the failure of the reverse-zombie argument.

  9. Hi Richard, nice to hear from you again and thanks for the comment.

    You are right that 1r is too general, and to point out that the dualist will surely admit that Maria does learn something new. But that is easily fixed. Here is (1r’)

    1r’ If qualitative facts are not reducible to, or deducible from, physical facts Maria should not learn anything essentially new about red

    The others can be changed as needed. Sure she will learn the ‘corelation facts’ as you say (actually she could probably know that in her room), but what she learns when she gets out of the room is that her experience is IDENTICAL TO, not merely correlated with, a certain brain process. That is, she will lean what her visual experience of red really is. So according to the dualist Maria cannot learn anything new about her experience of red that is essential for the experience being the kind of experience that it is (correlation certainly isn’t like that!); but this is exactly what she learns.

  10. according to the dualist Maria cannot learn anything new about her experience of red that is essential for the experience being the kind of experience that it is (correlation certainly isn’t like that!); but this is exactly what she learns.

    Ah, thanks, that clarifies the argument. This is now quite a departure from the form of the original Mary argument, and I must say I no longer have the faintest intuition that Mary learns any such thing (and I doubt anyone but a confirmed physicalist would have any such intuition). So the argument would then look to be question begging in the strongest sense. (Again, compare the original Mary argument, where even physicalists are at least prima facie inclined to find the premises plausible.)

  11. Hi RC,

    I for one never had the correct Mary intuition. The fact that so many people do have the ‘correct’ intuition is just evidence that dualism is part of the folk theory of consciousness, but as with most folk theories this is refined and eventually superceded by science, which in turn trickles down to the folk intuitions. Check again in 75-100 years and even dualists will find the Maria cases prima facie plausible.


    who’s who and which is which??

  12. Well first of all Brandon (Hylomorphist) – the first post in the thread.
    I might have a little more look for my reference (that I found and lost) before I explicitly out one of the other 3 as a non reductive physicalist unless they care to do it themselves 🙂

    I guess you are a ‘confirmed physicalist’ and RC is a ‘confirmed dualist’ – explaining why your intuitions are opposite. I would say I’m unconfirmed but I think dualism bears the burden of proof in debates.

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