A Question about Mary

Hey Brainers,

Eric’s post the other day about conceivability arguments got me thinking about Jackson’s (1982) thought experiment about Mary the color scientist–in particular, about a conversation with Justin Sytsma that I had at the PSA this past Fall. Here is a sketch of the Mary case:

  1. Mary is a brilliant color scientist that knows all of the neural (i.e. physical) facts about color perception.
  2. However, Mary has never actually experienced color, having lived her entire life in a colorless lab.
  3. One day Mary goes outside and sees a red object, and has a new experience, the experience of red.

As Jackson argues, Mary has seemingly learned a new fact. But she already knew, all the relevant neural/physical facts. Therefore, she was learning something over and above these facts. A phenomenal, non-physical fact. Hence, objection to physicalism.

In convo with Justin he/we/I thought up a different sort of case, which involves (we may suppose) an even more brilliant colleague of Mary, named Gary. Working in the same lab, (1) and (2) above also hold for Gary, but the following is also true of Gary:

  1. Gary has built a device which he has attached to his brain. This device is a complex electrode array, over higher-level visual areas (essentially, a more advanced version of this), which receives inputs regarding activation patterns (distribution, firing rates, etc.) from a computer.
  2. Using his knowledge of the neuroscience of color vision, Gary creates a program that provides inputs to the array such that their stimulation induces in himself an experience of red (let us say a just a crude blob of red–nothing so fancy as a red apple.)

Now, Gary seemingly learns something new as well, namely, what it is like to see red. However, for my part, I don’t find the Gary argument remotely compelling as an argument against physicalism: I find it less compelling to claim that the fact he has learned is not, in some sense, physical. But Gary’s case is, as far as I can tell, analogous to the Mary case, except that the causal route by which he gains his knowledge of red depends rather crucially on his knowledge of the neuroscience of vision.

So, if I am right that the Gary argument fails, then I find myself wondering: (i) why does the argument fail? and (ii) does the Mary argument fail for the same reason? While I find myself endorsing (ii), I am not sure what to say about (i), exactly. So, what do people think? Am I a missing something here?


  1. woodchuck64

    Sounds like Dennett’s RoboMary (https://ase.tufts.edu/cogstud/papers/RoboMaryfinal.htm). In both cases, RoboMary and Gary “learn” “raw feels” by self-manipulation without requiring the outside world.

    That still means to me that 1st-person view trumps 3rd-person view on at least one detail, but then I’m not sure that the 1st-person knowledge of “raw feels” should be put in the same category as 3rd-person knowledge of facts. It feels like a category error.

    If you imagine that Gary/RoboMary fool around randomly with their sensory equipment, they might just create a “raw feel” that has absolutely no 3rd person correspondence at all in the real world. Would that really be knowledge that would challenge physicalism?

  2. I’m assuming that physicalism in this case refers to the fact that everything (emotions, feelings, representation states and reasoning) boils down to the atomic level (or deeper but rooted in the physics of the world). If that is the case, neither Mary nor Gary is an argument against physicalism. In both cases they are missing a process that converts from the one physical state (an explanation of the concept of “red”) to another set of physical states (the experience of “red).

  3. Eric Thomson

    I was wondering the same thing: if I don’t feel the pull of Mary (at all), then the pull of Gary is the same. Though it is useful to have different permutations to show why I don’t feel the pull. Swamp Mary is really cool, for instance.

  4. DanCT

    > Using his knowledge of the neuroscience of color vision, Gary creates a program that provides inputs to the array such that their stimulation induces in himself an experience of red.

    I may be missing something, but doesn’t this just assume the truth of physicalism (i.e. Gary deduces the phenomenal facts from the physical ones)? Maybe that’s why it is not compelling as an argument against physicalism!

  5. Joshua Stern

    I don’t get it, the Gary case seems to me a complete refutation of the Mary case, and correctly so.

    The whole Mary case I believe to be just a bad intuition pump. Take the case of Soupy. He has studied cream pies for years and knows all about them, but then one day he opens the door and gets hit with one for the first time. He knows no more physical facts than before, but now has to wipe his face. Is this an insight?

    Or, I have the complete plans to build a reproduction the Wright Brothers plane. But, I haven’t built it yet. When I build it … I don’t just hold the plans, but the object. There is a difference in the physical facts between the before and after for Mary, for Gary, for Soupy, and for me. Any difference in experiental facts and qualia only follows from that.

  6. I am going to try and do this in one go:

    @Woodchuck: Gary is definitely similar to RoboMary, though how similar I am not sure. I will have to look at the Dennett (again.) The “category error” point about the 1st and 3rd perspective is very similar to stuff that Nagel in his famous paper. Importantly, he did not take his argument to undermine physicalism, however.

    @Umesh + Eric: physicalism in this case is the view that all the facts are either microphysical facts or facts that metaphysically supervene on the microphysical facts (e.g. biological facts.) I also do not find the argument compelling in an intuitive sense. So, this is more supposed to be a different “permutation”, as you called it, Eric.

    Similar to the point you make umesh: by the definition of physicalism, a physicalist will reject that Mary knows all the physical facts, since for her, phenomenal facts supervene on physical ones. She does not know about some of the physical facts of color vision (the subjective ones.) So the physicalist should deny the set up. By definition, the Mary does not know all the physical facts, and when she goes outside, she knows a new one. Big surprise.

    The reply, roughly, is that one must be able to “deduce” the supervening facts from the subvenience base (see Chalmers’ (2002) discussion of Type-C materialism) I don’t by it, but this at any rate takes us away from Mary, and suggests the argument really depends on other metaphysical claims. Mary is not really doing much work.

    @Dan: I think you are right that the Gary case might somehow presuppose physicalism, but then, I think the Mary case (without elaboration) assumes the falsity of physicalism, as I suggested above. As you say, if he has deduced the phenomenal from the physical (which I am not sure about), then this might meet Chalmers’ point about deduction, mentioned above.

    @Joshua: that would be nice if true! What several people allude to, and I think is right about the Gary case, is that it involves, in a sense deriving the phenomenal fact from the physical fact. I don’t think it undermines the Mary argument, but I do think the Gary case might be useful as part of a more comprehensive argument.

    (apologies for any incoherence in the above. A pretty wicked head cold is making it very difficult to think about philosophy right now!)

  7. Joshua Stern

    On further consideration, I want to completely reject the Mary argument as a simple matter of confusing use and mention.

    Say that Mary has been studying the Internet Explorer for many years, and after great effort has duplicated the code, and holds the duplicated code in one hand. But then she puts the code into her computer for the first time and actually runs the program, and it works! Does she now “know” something that she didn’t know before? Yes! But *obviously* so, because she has, for the first time, USED her knowledge!

    One could go the other way as well, an old analogy of “Einstein’s Brain” I think is from Godel, Escher, and Bach? Mary’s notebook holds all that she knows about red. Does the notebook “know” about red? Does anyone reading the notebook “know” about red? Is the notebook, Mary’s mind?

    Get back to the first. The essentialist (or whoever the Mary argument is supposed to support) will probably grant my claim. “Yes!” they will crow, “you are exactly right, and this only PROVES that the quale is an irreducible product of Mary’s brain and intelligence! The computer is fine for Internet Explorer, but only the human mind/brain can do ‘red’.”

    I admit, I do not know how to make my own argument more convincing, but believe it comprises much of a conclusive anti-Mary argument. Then again, it is not really anti-Mary, nor pro-Mary, but clarifying of the issue, one hopes. Let me try one more tiny point, the error was in ever imagining that the study of X would ever be the same as the implementation of X, and it doesn’t matter whether X is red quale or a physical cream pie.

  8. Charles Wolverton

    The problem I see in the Mary scenario is that “know” usually goes undefined. I look at it from a Sellarsian perspective, and see it as a version of the issue addressed in Empiricism & Phil of Mind.

    In brief, for Sellars “knowing” is the product of social interaction (or presumably something equivalent like reading a trusted technical journal with peer-reviewed articles) which provides “justification for what one says”. So, Mary “knows” all about the technology of an experience people call “seeing red” due to such reading and possibly other social interactions but has never had the experience herself. In particular, when she first encounters red she won’t “know” that the experience corresponds to what people commonly call “seeing red” until she learns that by interacting with others who react to what she is encountering by saying “I am seeing red”. Then she will be able to respond to recurrences of that experience by saying “I am seeing red” and justify that claim by referring to that social interaction.

    I suppose an alternative way of acquiring justification could be, in principle, monitoring her own brain activity and noting that it corresponds to what she knows from her studies happens when people experience what they call “seeing red”. The justification would come from the credibility of the sources of her knowledge of that brain behavior.

    In short, when Mary first encounters red she may (it’s not obvious to me that phenomenal experience itself doesn’t also have to be learned) have a new experience – and even say “wow!”, although I don’t understand why that’s relevant – but she will acquire new knowledge only via a process of social interaction.

    Note: The general idea is similar to Davidson’s description of learning a language as a process of “triangulation” and to Wittgenstein’s “beetle in a box” thought experiment in his Private Language Argument.

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