Synesthesia is a phenomenon in which the activation of one sensory modality leads to experiences in a second sensory modality: one common form of synesthesia is the perception of letters or numbers as inherently colored. This phenomenon has, I think, received relatively little attention from philosophers--although there are related remarks scattered throughout Wittgenstein's 'later' writings--in part because after years of neglect by psychologists, it has only relatively recently begun to receive sustained attention from them. Consideration of the phenomenon may well offer insights into a range of questions in the philosophy of mind, including the philosophy of perception, such as: the relation between different sensory modalities; whether different sensory modalities represent the world differently; and even the nature of consciousness, insofar as one problem for accounts of consciousness is explaining the experience of sensible qualities--sometimes called 'qualia', for qualitative experiences, a topic that consideration of synesthesia might well illuminate.
The answer seems pretty clearly to be yes. Touch and hearing both convey information about dimension. Think, for example, about the fact that a sound can be above you, or in front, or two the side. Or think of how you could tell that object A is taller than object B, but object B is wider than object A just by using your sense of touch.
If you're interested, here's a link to a video about a remarkable Turkish painter, blind from birth but able to convey subtle information about perspective.
"Different qualia or different attitudes to the same qualia?" That seems an intractable question. It should make us suspicious. Maybe the very idea of qualia (as postulated by some philosophers) is the source of the problem. For sceptical thoughts along these lines, see Dan Dennett's justly famous paper, "Quining Qualia", readable here.
Interesting question! There are philosophers who would seek to undermine the whole picture of ourselves that is presupposed by your question. Some of them argue that we do make direct contact with the objects we touch, feel, smell, hear, and taste and that the idea that we only directly deal with sensations (or what is sometimes called "sense-data") is an illusion brought on by people like Descartes or, in the 20th century, by Bertrand Russell or A.J. Ayer. But I am inclined to think we do not directly feel and see what is around us; while I think we do (under normal circumstances) relaibly see and feel "what is really out there" this is mediated (in my view) by sensations, our visual field and so on. On this view, skepticism of an even very radical sort is conceivable. It is logically possible (I suggest) for the movie the Matrix to be right; we merely think we see what is really there, but we are being manipulated by complex computers to have the sensations we are having.
One other matter to consider: Your first question "What is reality?" has been at the heart of a great deal of philosophy historically. One of the important points that has been made is that when people worry whether they only face a world of appearance, they can at least be confident in the reality of appearances. Augustine used such reasoning in his reply to the skeptics of his day who seemed keen on doubting everything. Augustine countered that there are some things that cannot be doubted (the self, and appearances, among other things).
great question -- though it's not like there is 'an' answer here, though there is much to be debated as you formulate your own anwer. For one thing one must try to separate 'the 'experience from the language we use to speak about it and focuse on the experience. And anecdotal (incl medical) evidence seems to suggest it's no uncommon for people to report things, under anesthetics of various sorts, that they are having terrible pains but somehow don't mind them. That prima facie suggests that that very experience, the painful one, doesn't have to be a cause of pain, so to speak -- which suggests it is NOT inherent in pain to be avoided/disliked. (Lnguage complicates this b/c we might choose to use the word pain in that restrictive manner and thus claim those un-minded experiences do not earn the label 'pain' -- that's a semantic choice but it doesnt seem to effect the ontological conclusion.)
hope that is helpful ...
Wow, fantastic email -- getting at the heart of some major philosophical ideas and movements. Empiricists tend to stress the role of perception/experience in producing knowledge, while rationalists tend to promoe the role of reason, often arguing on the basis of such considerations as those you mention. A couple of quick thoughts about the specifics of your message. Your example of a problematic perception (spinning cube looks like sphere) doesn't quite/fully show that perception is problematic, partly because some other perception is relevant to getting at the truth, ie seeing the cube not spinning. The rationalist might say that reason is needed to process these otherwise conflicting perceptions, but even if this so, it does seem that perception is playing a key role in generating our knowledge of the world (that a cube exists, and that, when spun, it looks spherical) -- so what you've raised is a kind of problem for perception, but not one which obviously (to me anyway) undermines the importance of eprception in generation knowledge. Second, you mention the 'gap' between reality and minds -- and probably need to say more there. Even if everything we come to know about the empirical world were ultimately, in some way, derived from perception, it remains possible that perception is 'veridical' -- gives us true information about the world -- so the sheer fact that our access is mediated via perception does not entail that perception isn't veridical, or even direct .... This doesn't fully answer your excellent question -- how do we know we have knowledge not just perception? but aims to suggest that perception may well play important roles in generating knowledge despite the two kinds of worries you raise ....
hope that helps!
It's pretty clearly possible to look without verbal labeling, since animals and infants do that. But whether we can just look at something 'as it is' isn't so clear. One obvious problem: our sensory systems (brain included) do a lot of processing of the information they take in, and this starts early in the process - long before we get to anything over which we have conscious influence. So if that doesn't fit the "seeing as it is" bill, we're already out of luck. But there's another problem: what would count? My cell phone sits beside me. What would it mean to look at it as it is? Among other things, it is a cell phone. If I don't recognize that, there's an obvious sense in which I don't see it as it is - or at least, not for what it is.
But even if we stick to the intrinsic characteristics of the thing apart from its uses, which of the countless many count? There are far more physical facts about my cell phone than my beleaguered brain could ever cope with. Not only that; many of the really important properties of my cell phone are at the level of microchips and the like - not to mention that the thing is made of submicroscopic molecules.
We can certainly train ourselves to focus on "basic" features like color, shape, etc. An artist might need to do that to make a good drawing. So no doubt we can do some of what you probably have in mind. How much is partly a question for the psychology and physiology of perception. But just because our perceptions usually contain more "interpretation" doesn't mean we aren't seeing what is. After all: those interpretations may be true!
Great question -- and in fact you have your finger on a version of what is ultimately perhaps the strongest argument for a mind-body dualism -- ie the view that mind and body/matter are completely distinct sorts of things. One way to put it is this way: with eyes closed I am seeing (say) a shining sun; but it isn't the real physical shining sun I am seeing (b/c my eyes are closed); therefore I am seeing some non-physical thing, a mental thing, a mental image or representation OF the physical shining sun. Therefore there exist mental things which are distinct from all physical things .... So the phenomenon you invoke is at least strongly suggestive that there are two kinds of seeing, or two kinds fo things seen: mental and physical .... Now, having said that, there are various ways phlosophers have resisted these kinds of arguments -- you might want to look up a philosohper named JJC Smart, and his work on the "identity theory" (denying dualism) to see how he resists these arguments .... Also one other point to make: the way you frame the question is that "I close my eyes and see the SAME postcard and picture ..." You might want to think about what you mean by "same" here -- the argument I just presented suggests that what we see with eyes closed is not literally the SAME things we see with eyes open (the former are mental in nature the latter are physical) -- so do you think these are literally the 'same', or merely (say) 'similar' or 'resembling'?