Picture: bike. Sam Coleman returned in a recent paper (JCS vol 16, n0 2-3) to the old perennial of Mary the colour scientist.  As you may know, Frank Jackson’s story about Mary was intended to establish that there was something important – qualia – which the simple physical account of the world omitted. Mary, we’re told, knows everything that could possibly be known about colour from a scientific point of view (far more than any living scientist knows, or could know).  She knows all the physical facts. But she has never experienced colour; when she sees a red rose for the first time, doesn’t she learn something new – ie what red looks like? If you agree, then, it is argued, you must agree that there are things in heaven and earth not dreamt of in physicalist philosophy.

One standard riposte to this line of argument is to deny that Mary learns any new facts when she sees red for the first time:  instead, she merely acquires a new ability. Now she can recognise red, when she couldn’t do before; but she doesn’t actually know any new facts about redness or the human optical system. (After all, the phrase ‘she knows what red is like’ literally suggests that she can give a list of things which are like a red object, and say whether the colour of a given object resembles red or not – which sounds a lot like recognition.) We might mention other abilities; the ability to remember or imagine redness, in particular – but none of these involve new knowledge in the ordinary sense, any more than acquiring the ability to ride a bike involves learning new facts. You can read as many books about bicycles as you like: you’ll still fall off the first time you get on one.

Coleman aims to knock this line of argument on the head, not by refuting it but by showing it to be irrelevant. Most attacks on the Ability Hypothesis, he says, address what he calls its inner face directly. They seek to show that what happens to Mary cannot be boiled down to the gaining of an ability – perhaps because all such abilities involve factual knowledge – or they set out to show directly that Mary does indeed learn new facts.  These strategies tend, he says with some justice, to end up mired in a clash of intuitions with no clear way forward.

Instead, then, he concedes that if we wish, we can see what happens to Mary as the acquisition of some new abilities; he addresses instead what he calls the outer face of the problem. What about the analogy of bike-riding? Proponents of the Ability Hypothesis say it does not depend on factual knowledge, and it’s true it doesn’t come from academic book-reading. But what does it involve? Surely it’s all about keeping our balance? That’s a matter of teaching your muscles how to respond quickly and appropriately to certain sensations of tipping over.  So hang on, it actually involves knowledge of what it feels like to wobble – what certain kinds of phenomenal experience are.  Is this kind of knowledge factual knowledge?  Never mind the answer for the moment – all we need do is notice that this is exactly the kind of question we were asking about Mary’s experience of redness in the first place. The Ability Hypothesis has merely taken us back to where we started – so we need not waste our time on it.

A neat piece of footwork, I think, and Coleman’s analysis of the phenomenal element in abilities such as bike-riding, ear-waggling, and the use of chopsticks provides an interesting new insight, worth having in its own right. (Readers may be interested in the Phenomenal Qualities Project, whose three-year mission is due to begin next month; Coleman is co-investigator to Paul Coates and the list of project members includes some stellar names.)

Where are we left with Mary meanwhile, though? Should we now accept the refutation of physicalism she represents? No, I would say, but then again yes.

One thing that’s sure about Mary is that if she does acquire new knowledge, it is knowledge of some special kind. It isn’t the sort we can write down and transmit in words – that much is true ex hypothesi, because if it were that kind of knowledge, it would be among the things Mary already knows. It’s tempting to denounce this kind of knowledge as metaphorical or worse, but let’s merely ask whether it’s fair to expect the theory of physicalism to include it.  Theories, after all, are expressed in words, and typically written down; if we’re dealing with facts that can’t be dealt with that way it seems only reasonable to conclude that no theory could deal with them and that they must remain extra-theoretical.  Physicalism might then be incomplete in some sense, but we have no reason to think it isn’t as complete as any theory could be.  How much is it reasonable to ask?

And yet, and yet…  We’re talking here about what things are like;  this somehow still feels like a problem where more could be said after all. We can’t expect that our theories should deliver ineffable reality itself, but doesn’t it seem that there is some tantalising last elucidation obtainable here, if only we knew how to go about it?


  1. 1. Spike says:

    Hey Peter, short-time reader, first time poster..
    I’ve been reading a lot of cog. psych. and similar lately, enjoy consciousentities (and love disgressed! Laugh-out-loud funny.)
    I know it’s not your problem, but since you brought it up: Doesn’t the Mary problem change if you replace ‘red’ with (say) ‘high C’, if Mary has been playing on a 1-octave piano? Or even if we replace ‘red’ with (say) ‘dark red’, when Mary has reds, but never a ‘dark’ one?
    I have a sneaking suspicion that a lot of the problem with ‘red’ (the experience of seeing something that is red) is that it is a physiological category, or maybe ‘conceptual dimension’. Red is not a composite of other categories or dimensions, nor can it be extrapolated or interpolated from other non-red experiences. This makes it impossible to communicate the concept of ‘red’ to a listener if you have to assume the listener does not already have the concept: There’s no way to ‘get’ to the concept from your shared universe of concepts. So the problem is not that Mary is experiencing something metaphysical, the problem is that Mary until seeing the rose is unequipped to understand the word ‘red’ in reference to a subjective sensation. She is not linguistically competent, so she *cannot* know everything there is to know about red. If she has played a one-octave piano and you tell her you’re going to play ‘high C’ for her for the first time, I’m sure in this case too she learns something – we all have this experience multiple times per day, of perceiving something not exactly like anything we have perceived before – but I don’t think she’s surprised, nor would anybody expect her to be, nor does anybody offer this as a conundrum.

  2. 2. Lloyd Rice says:

    I don’t have the original Jackson paper and the JCS site lists the latest issue as vol 15, #12 (and anyway, I don’t subscribe, so I may or may not be able to get the paper there). Anyway, I did look at Chalmers’ discussion in “The Conscious Mind”. He notes a 1992 paper by Thompson, raising the issue of whether Mary was biologically whole or color blind. We are to assume that her eyes and brain worked normally, in which case, she would have seen red whenever she rubbed her eyes. So, ergo, she is color blind.

    Anyway, these are all assumptions. For us materialists, whenever she first experienced looking at a red object, she would have “seen red”, period. So all of Chalmers’ (and presumably Jackson’s) assumptions are just that, no basis for conclusions about phenomenalism.

    Your issue of bike riding rests on some shakiness having to do with the learning of skills vs. cognitive knowledge. Much of the former involves subconscious processing so we might conceivably have learned to ride, yet never have really experienced wobbling. I’m not sure where Coleman’s comments on this fit in.

  3. 3. Lloyd Rice says:

    The Coleman paper is available on the PQP site (via your paragr 5 ref).

  4. 4. Lloyd Rice says:

    I need to add a bit more to the 2nd paragr of my comment (#2 above). One of the questions was whether Mary “knows anything new” whenever she first sees red. I.e. is the “red” experience somehow not encompassed by her vast prior physiological knowledge? I think the problem here is the initial assumption that she could somehow “know all there is to know” without having had the experience. To me, that is a fundamental contradiction. For me, the experience itself would be new, even though she might have been able to predict that something new would happen to her. That does not make the experience epiphenomenal (as I understand that word).

  5. 5. Lloyd Rice says:

    I read the Coleman paper. Ability hypothesis? Physicalism? Phenomenal knowledge? Factual knowledge? There is WAY too much pinhead dancing going on here! What most disappoints me is that this paper has nothing at all to say about what actually happens in Mary’s brain when she first looks at that tray of red and green tomatoes. It’s all about the definition of “fact” (I think).

    I think I never should have commented on this topic. If you like, Peter, you could delete all of my comments above (and including this one). I’ll chime back in when there’s something to say.

  6. 6. Peter says:

    I’d prefer to keep the comments unless you really want them deleted, Lloyd. There is certainly something in your point about pin-head dancing, though.

    Many thanks, Spike. Good point about the significance of choosing red or some other example. Discussions of this subject nearly always focus on seeing red for some reason, although personally I think I find smell the most ineffable of the senses. That might indeed have something to do with the difficulty of extrapolating to new smells, as against the relative ease (perhaps) of working out what a darker shade of red, or the same note an octave higher, is going to be like. I don’t know exactly where that takes us on the underlying qualia issue – there seem to be a number of different ways you could go – but it seems a promising avenue for further thought.

  7. 7. Lloyd Rice says:

    So be it. Keep up the good blog and I’ll stay in touch.

  8. 8. tom brokaw says:

    I have knowledge of what red looks like. Does this make me more knowledgeable than the pre-exposed Mary? I think it is knowledge but it cannot be classified in the same way most facts are. ~2 cents

  9. 9. tom brokaw says:

    do humans not operate backwards? when we see red, only then do we dissect it into it’s wavelengths or what have you?If we did not experience color, we would have no reason to investigate it or discover it. Being 16, i know my uneducated thoughts don’t carry a lot of substance but i think there is a large possibility of “things in heaven and earth not dreamt of in physicalist philosophy” existing.

  10. 10. BnB says:

    How could Mary know everything scientifically possible about the color red and not know what red looks like? Part of scientifically knowing everything about something (a color, in this instance) is by knowing everything that one could possibly know from observing that something directly and by knowing everything one could possibly know by performing repeatable tests on that something.

    Therefore, the set of everything one could scientifically know about anything includes what you can gather from directly observing the something in question, such as what it looks like, tastes like, feels like, smells like etc.

    So, if Mary is to know everything scientifically possible about the color red, she must know what the color red looks like. But the argument says that she knows everything scientifically possible about the color red but does not know what red looks like. This leads to a contradiction, so I say the whole argument is invalid.

  11. 11. Lloyd Rice says:

    BnB: Hey. You can’t get too literal about this stuff. After all, these are philosophers’ questions. It’s all just a game. I think you are correct about scientific knowledge, but it doesn’t matter, one way or the other. Call me the cynic.

  12. 12. Holomorph says:

    ´what something looks like´ is no knowledge. Thats an experience, its a phenomenon. Its a special brain state, a special configuration of the brain resulting from light which enters our eyes. But all these things are no knowledge. I mean, you can know everything about a table, but that does not mean you ARE a table. Obviously, there are many brain experiences and brain states Mary never had. But this is no problem to a physicalist´s world view. It does not imply that there is some missing knowledge.

  13. 13. Luis Garcia says:

    Here is another tale: Mary the philosopher of mind. Mary is a brilliant philosopher of mind who, since the early eighties, kept a state of the art knowledge of her field (so she is brilliant but much more human than her famous namesake the colour scientist who, of course, she has heard of). In 1992 she happens to be confined in a tropical island. There she has everything to have a very pleasant time (no need to make this more uncomfortable than necessary for poor Mary), but no means to keep in contact with her colleagues. In April 2009 she is finally released, she gets access to a computer connected to the internet and comes across Conscious Entities which finds very interesting. And then she discovers in a recent post that the thought experiment about Mary the colour scientist is still discussed. Is she surprised?. Does she learns something new about philosophy of mind?. This is my tale, so yes: she is surprised and, well, she may learn something, not very comforting though.
    Leaving jokes aside, the longevity of this thought experiment cannot be denied, and it must mean something.
    However, I find it very difficult to think of Mary (the colour scientist this time) really acquiring any knowledge when experiencing colours for the first time. Let us suppose that prior to her release, she has written a complete treatise on her knowledge (who knows how many terabytes in a hard disk). Then she is released, she sees the red rose and she learns something essential about colour vision. What new facts does she has to add to her treatise? Is it just a question of adding or does she also have to correct some parts of it? Or maybe Mary cannot amend the treatise in anyway so it was already complete? (no room for new knowledge, in that case).

  14. 14. Shankar says:

    I don’t think bike-riding is a good analogy to seeing the color red. The latter is an entirely new concept to someone who has never seen color, but the feeling of wobbling when someone tries to ride a bike for the first time is not something that cannot be extended from past experiences in motor control involved in other activities.

    It is entirely conceivable that someone who is extremely bright (in this context) could pick up the skill of riding a bike by just reading about it.

  15. 15. Neil Hammond says:

    I think Luis makes a good distillation of the problem in the question of how, or if, Mary would amend a treatise on “red” that she wrote before directly experiencing the colour. As Mary is typically portrayed as superhuman, I think we can fairly insist that she could have a self-reflexive ability beyond humans – to have direct knowledge of her own brain states (I know this makes her an objective spectator of her own subjective experience, but it is no more ludicrous an assumption than the central premise of the problem in my opinion). So after “experiencing” red you could argue that what she has learnt (and what she can then add to her treatise) are: “the brain states that are engendered in the mind of someone with her specific physical vision and neurological hardware who experiences red for the first time after previously knowing all physical information which it is possible to know about red”. This argument presupposes a physicalist interpretation (that the experience is summed up by the brain states engendered in the viewer), but leads to the paradox that she has acquired new knowledge (about red), which violates the original premise. So I think there is a consistent line on this from the physicalist perspective.

  16. 16. Neil Hammond says:

    I’m not versed in this field (aside from being a big fan of this blog), so forgive my naivety. I think my point above could be put more accurately. With sufficient knowledge not only of the physical characteristics of what “red” is, but also of how the entire brain and perceptive system functions, Mary would have the necessary information to simulate her first experience of red (dream about it for example) to such accuracy that she herself would be unable to tell the difference herself between her first experience of red, and her expectation (simulation) of what that first experience would be like. In this case she acquires no new knowledge and “qualia” are then defined as something like “those physical data which are a little beyond our capacity as humans to conceive of as purely physical data.” This would be close to what I think personally.

  17. 17. Luis Garcia says:

    I am no more than an occasional curious reader, Neil, and I am sure than naivety pours continually out of my comments. Anyway, I have found yours very interesting and I am glad mine has contributed to provoke them in a way.
    Mary has to known everything about brain states related to colour vision. Then (your comment #15), if we discard the possibility of Mary inducing brain states to herself, she will learn something new when experiencing colour by the first time, and all of it from a physicalist point of view. So, in that case, the fact that Mary learns something new would prove nothing at all about physicalism. On the other hand (comment #16), if we enhance a little bit more Mary’s powers and allow her to induce brain states to herself, she does not learn anything new when experiencing red for the first time.
    Seeing it that way, the thought experiment tells us nothing. I guess this happens quite often with thought experiments aimed to rule out physicalism. Maybe the mere question of whether physicalism is true or not is sort of misconstrued, specially if we try to address it by way of simple intuition-appealing (-cheating?) thought experiments. Maybe physicalism can’t be neither ruled out nor proven by now, but I don’t think this pose any big problem. I am persuaded that physicalism, true or false, is the only or at least the most promising standpoint we presently have to search for shareable knowledge on the field of consciousness. If it is not true, our search will lead us to that conclusion sooner or later and most probably will provide us with the new standpoint at the same time.

  18. 18. Kar says:

    Let me the contrarian chime in a little bit…Mary learnt something new: How to use a new instrument, her eyes, to distinguish red from other colors. Presumably, Mary had to carry a “color-meter” before to help her tell different colors because her eyes were not “calibrated”. After seeing red (and other colors), now she can get rid of the little handheld color-meter, and completely rely on her own pair of eyes to finish the job. As Peter put it best: “Abilities don’t matter?” I added the “?” because I think that is the original intent. Very good question. But they do matter. If not, the ability to solve a second order differential equation will not count as knowledge, the ability to pick the right person to lead a business unit will not count knowledge, etc, etc..then what will? After all, what is knowledge for? It is to help the species’ survival, from the evolutionary standpoint. Knowledge is to help us gain/enhance the ability to survive better. No?

  19. 19. Shankar says:

    Re-reading this post, I disagree somewhat with this statement – “We might mention other abilities; the ability to remember or imagine redness, in particular – but none of these involve new knowledge in the ordinary sense, any more than acquiring the ability to ride a bike involves learning new facts.”

    The ability to imagine red is in no way inferior to actually seeing that color. If someone could imagine red, he/she knows exactly what red is (in the phenomenal sense). Also, when it comes to remembering, one needs to be careful with the wording – “remembering the color red” is different from “remembering having seen the color red” – the former is a phenomenal experience while the latter may not necessarily be.

  20. 20. Sam Coleman says:

    Hi, I only just found this post.
    Just a couple of comments that occur to me:

    1. Re: Comment 14 – It seems to me implausible that someone who knew what the experience of wobbling/balancing was like could learn to ride a bike just by reading. But that’s beside the point anyway – the point is this person knows what wobbling feels like from some first hand experience, of learning to walk, walking, falling etc. If you want you can substitute ‘learning to walk’ for ‘learning to ride a bike’ and keep my argument the same. I’m happy with that.

    2. Re: Comment 10 – If you just assume that redness/the experience of redness can be captured by science then you don’t even think there’s an interesting question regarding physicalism. The point is that in the sciences we typically try to explain the appearances of things to human beings in more reductive, scientific terms. For example, we explain the appearance of lightning in the sky as electrical discharges. Similarly, physicalists presumably hold that there is some sort of brain-related story concerning how we have experiences of redness, a story that captures and explains the nature of the experience and its physical basis. Well it’s THAT story that Mary knows all about, and yet she doesn’t (it seems plausible) know what redness is like until she sees it. That’s the intuitive power of Jackson’s thought experiment.

    3. A few comments seem to toy with the idea of Mary inducing the ‘brain state’ of experiencing red before she sees a red thing. That’s fine, but it rather misses the point. The puzzle is not over whether and how Mary can get to experience redness in her black and white room, the puzzle is over why with all the physical information to hand (information that can presumably be communicated in a black and white format – if not why not?) she still doesn’t know the nature of a certain property: the character of an experience of red. But physicalism claims that all the facts are physical facts. How can this be?

    It’s great to see some discussion of this stuff going on outside of purely academic forums.

  21. 21. Peter says:

    Many thanks, Sam.

  22. 22. Vicente says:

    I think I get to this discussion a bit late, but there are a few ideas I would like to share, and better late than never:

    In formal terms:

    1) We can question if Mary could have learnt all that knowledge about color without having the previous experience of color.

    2) Is the tale assuming that all other humans around Mary are colourblind too. Or Mary was told about color experiences, despite she did’t experience it directly?

    3) Let me put a more realistic example than Mary’s: Let say I am a biophysicist doing research about organs that allow animals to sense magnetic fields or electric fields, like sharks or geese. And I manage to get all possible knowledge about it, I fully understand all uderlying sensing mechanisms. Still, I don’t sense magnetic or electric fields.

    But because I have other senses, I can try to imagine how it is for example to feel the Earth’s magnetic field, considering I know how a compass needle behaves in the field. So I can guess that, when my head longitudinal axis is alligned with the field, I “would” feel nothing, and progressively as I rotate my head, I “would” start feeling a “soft torque” on my neck that takes a maximum at 90º and goes to zero at 180º and simmetrically to 360º, sort of. Or maybe it causes a completely different sensation like internal shiverings who knows.

    Mary is even in a worse situation, she cannot even try to imagine how would red colour look like. So I am closer than Mary to really have all that a physical approach to the problem can offer to me: the theoretical and experimental background, plus some imagination based on other senses and knowledge.

    Now one day I am allowed to go through the experience. I can really access qualia corresponding to magnetic field sensing.

    The point is that I have: “SOMETHING MORE”, “SOMETHING DIFFERENT” that I couldn’t get at all by physical means, that only the direct phenomenological experience can give me. Wether you call it knowledge, cognitive knowledge or ability it is absolutely irrelevant. It is new and it is different.

    I could take some objections:

    – How would I be allowed to have the experience? I doesn’t matter, if I am not allowed it means there is something existing out there I cannot access by physical means.

    – Maybe the new qualia, is already like old qualia, like the mechanical sensation I described, so there nothing really new or different in terms of experience. Nevertheless, for Mary it is new and different, so objection solved.

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