Do I know what it's like to see red when I'm not looking at something red?

I've seen red. But as I am writing this sentence, I am not seeing red (my eyes are closed). So do I know what it's like to see red?

Let's try "no". Then the knowledge of what it's like to see red is really evanescent: it's only present when actually perceiving red. Moreover, it seems that what's relevant is not just the perceiving of red, but my attending to apparent perception of red. So it seems that I only know what it's like to see red when I attend to an apparent perception of red. But when I do attend to an apparent perception of red, then I surely know what it's like to see red. So I know what it's like to see red when and only when I attend to an apparent perception of red. This now makes me worry that "I know what it's like to see red" is just a more colloquial way of saying "I attend to an apparent perception of red". And if that's so, then the Mary argument for the nonphysicality of qualia is undermined. Furthermore, I think a lot of the intuitive plausibility of the argument comes from imagining oneself in Mary's pre-seeing-red stage, and imaging the kind of curiosity we'd have about what it's like to see red. But if this curiosity is a desire for knowledge that one doesn't have, and if I don't know what it's like to see red, then it's surprising that in Mary's position we'd have curiosity, but when my eyes are closed and I am not seeing red I have little curiosity about what it's like to see red, even though I don't have that knowledge. This suggests, in turn, that the curiosity that we would have in Mary's position isn't a desire for knowledge, but a desire for perception. So, all in all, the "no" answer seems harmful to the Mary argument.

What about "yes"? Intuitively that's the right answer. Surely people know what it's like to have perceptions that they aren't occurrently having. But now it's not clear what my knowledge of what it's like to see red consists in. Does it consist in the fact that even when I'm not looking at anything red, I can bring to mind a memory of seeing red? I'm not very good at it. I search my memory and find a memory of looking at a red object. For a split second, a flash of a red v-shaped piece of tape on a climbing wall shows up in my mind, before disappearing. Is my knowing what it's like to see red constituted by my possession of the skill of producing such evanescent memory images? Then it sounds like know-how rather than the kind of knowledge that's relevant to the Mary argument. And my skills in this direction are quite limited. I've seen very good approximations to circles: for instance, the clocks in the classrooms I teach. But when I bring such seeing-a-circle experiences back to memory, the images are far from being good approximations to circles--instead, I get foggy images of arcs that don't even meet up.

All in all, I am puzzled. I just can't put my finger on what it is that I have when I know what it's like to see red...

Knowing what and knowing that

Consider this real-life sentence:

1. Once your dog knows what "sit" means, he will be happy to please you.

So it appears that the following sometimes happens:

2. The dog knows what "sit" means.

But surely dogs don't know semantic propositions. So, (2) does not entail that anything of the following form is true:

3. The dog knows that "sit" means ....

Dogs don't need to know semantic propositions to understand commands. Likewise, a small child don't need to know a proposition of the form <"Table" means ...> in order to know what "table" means.

Now it could be that this is something special about meaning, that we simply say that someone or something knows what something means provided simply that he, she or it grasps it, without him, her or its having to know any semantic proposition. But I've also toyed with the idea that when we say "x knows what/where/when n V" (where "n" is a noun and "V" is a verb), this should not be analyzed as attributing to x knowledge of the relevant proposition of the form <n V m>. (In the above case, n is a word and "V" is "means".)

Sam was Gettiered in his coming to believe that 9x8=72. His innumerate teacher was saying "7x10=70, and 9x8=70, too", and Sam heard it as "7x10=70, and 9x8=72." And Sam never acquired any other relevant evidence. Then Sam does not know that 9x8=72. But maybe we should say that Sam knows what 9x8 is. For it doesn't seem right to say Sam doesn't know what 9x8 is.

Or suppose Spike has just heard a genuinely powerful argument for external world scepticism. It hasn't made him lose his beliefs, but the argument provided a defeater for his knowledge. So Spike doesn't know he has ten fingers, though he correctly believes it. It doesn't seem right to say Spike doesn't know how many fingers he has (i.e., what the number of his fingers is, to put it in the form I used above).

There is another possibility. It could be that to know what/where/when n V does require knowing that n V m for an appropriate m, but that we use "doesn't know what/where/when" to indicate something stronger than the denial of this knowledge.

I am not very secure in my intuitions about Sam and Spike, actually.

Mary's knowledge of red

Take Jackson's story: Mary is raised in a black and white setting, never experiencing red. She learns all there is to know about the physical constitution of the world. She leaves her black and white setting. She sees something red. She then comes to know something about the world which she didn't know before: she learns something about the experiences that other people have had. Hence the knowledge about the physical constitution of the world doesn't exhaust the possible knowledge about the world. Hence, the world is more than physical.

The standard objection to this is that this equivocates on "knowledge". Mary gains an ability, an ability to recognize and imagine red experience, say, after coming out of the black and white setting. Jackson has a rather nice answer to this, though. He supposes that Mary, after coming out of the room, toys with scepticism about other minds. But then she rejects the scepticism. In rejecting the scepticism, she does not gain any know-how. But she does gain the knowledge that others have that kind of experience, which she now has when she is looking at a tomato.

Here is a response to Jackson that has occurred to me. If Mary, before she saw red, really knew all there was about the physical world, she also knew that she will come out of her black and white setting, and that she will experience red. Before she has experience red, she can prospectively refer to that experience of red, the experience that she knows she will have (she can use "that" to ostend to that experience she will have). She also already knows that other people have had that experience. When she first sees red, she now "knows what that experience is like." But the only relevant fact in the vicinity, the fact that others have that experience, is a fact that she already knew. She now has a new way of pointing to "that experience" of hers: she can point to it introspectively, while before she could only point to it verbally ("dthat experience which I will have at t₇ upon looking at a tomato"). When she toys with scepticism about other minds, she temporarily loses the belief that others have that experience, and then she regains that belief when she rejects the scepticism. So Jackson is right in thinking that Mary loses something that isn't just know-how through scepticism and regain it. But perhaps he is wrong that what Mary loses through scepticism is what she learned about the experiences of others when she saw red. What she learned by seeing red stays there—it's just a new ability to refer to an experience of hers. What she loses is a belief that doesn't bother a physicalist.

I don't know whether the response stands up. I think it depends on the synonymy relations between indexical sentences. If I stand near near x and say "This is a tetrahedron" and you stand far from x and say "That is a tetrahedron", have we said the same thing? (Or, better yet, we both say "This is a tetrahedron", but your "This" gains reference through your pointing with your eyes, and my "This" gains reference through my pointing with my nose (with me closed-eyedly smelling the tetrahedron).) If so, then I think the response to Jackson goes through—we just have two different ways of fixing an indexical. If not, then it needs more work. But even so, if the difference between what Mary knew before she saw red and after she saw red is like the difference between a "this" belief and a "that" belief about something, it might not be a difference that should bother a physicalist.

Knowledge that and knowledge how

Here is an argument for the generally accepted thesis that knowledge-how is different from knowledge-that. Knowledge-that comes has two poorer cousins, true-belief-that and justified-true-belief-that. Knowledge-how does not seem to have such cousins.

In fact, knowledge-how seems more akin to true belief or justified true belief than to knowledge-that. Actually, it is possible to have knowledge-how in an area where one only has true beliefs. Suppose Georgina has all the skills and true beliefs that an automotive mechanic needs to have, but has very little in the way of knowledge. In fact, she has acquired her true beliefs about automotive repair from a fake psychic who, in a series of drug induced trances, uttered lots and lots of noises that happened to sound just like a series of lecture on automotive repair. Furthermore, Georgina has never actually touched a car. However, completely by chance, lightning has induced in her brain all the structures and motor memories that an experienced car mechanic would have. I am inclined to say that Georgina knows how to fix cars. The evidence of know-how is reliable execution, and she can do that. Suppose Georgina fixes your car. One can still question whether she knew how to do it. But if she reliably fixes cars, and does so consciously, with the right beliefs about how to do it, then she knows how to fix cars, no matter what source she got her know-how from.