Friday, October 30, 2009

A Very Simple Argument Against Any General Theory of Consciousness

Suspiciously simple, you might think. Here it goes:

(1.) No general theory of consciousness can be justified except on the grounds that it gets it right about certain facts known independently of that theory. Those facts include facts about the presence or absence of conscious experience in a wide variety of actual and possible beings that are unlike us in potentialy relevant respects -- beings like frogs, insects, weird sea life, computers and robots of various types, alien beings of various types, and collective superorganisms of various types.

(2.) Independently of a well-justified theory of consciousness, we cannot know, with regard to most such beings, whether consciousness is present or absent.

(3.) Therefore, no general theory of consciousness can be justified.

Are ants conscious? Block's Chinese Nation? Star Trek's shipboard computer? People will reach different intuitive judgments (as philosophical discussion amply shows) -- and there's no particular reason to think, anyway, that our intuitive judgments should track the truth about such matters. It seems that a well justified answer to these questions must lean on a well justified general theory of consciousness. But there are a lot of (actual and potential) general theories of consciousness, some of which imply that consciousness is very widespread, others of which imply that consciousness is relatively rare. We cannot choose among those theories without prior knowledge of how widespread consciousness in fact is -- the very knowledge that we cannot have without such a theory in hand.

It's a tight little vicious circle.

Wednesday, October 28, 2009

Curveball Illusion

I hadn't seen this curveball illusion before. Very striking and surprising. I haven't had a chance to look into the theory behind it yet, but it seems to me to suggest something strange about the mapping of visual input into peripheral space.

(Thanks to Paul Hoffman for the pointer.)

Wednesday, October 21, 2009

Epistemic and Phenomenal Consciousness

The term "conscious" is ambiguous between an epistemic and a phenomenal sense (as I'll explain shortly). So is the term "awareness". And "appears". And (in certain strained uses at least) "seems". There's a pattern here, a suspicious pattern. What's behind it?

First, the phenomenon. "Appears" is the clearest case, so let's start there. Sometimes we use the phrase "it appears to me that _____" simply to express a judgment -- a hedged judgment of a sort -- with no phenomenological implications whatsoever, that is, no implications about what's going on in one's stream of experience. If I say, "It appears to me that the Democrats are headed for defeat", ordinarily I'm merely expressing my opinion about the Democrats' prospects. I'm not attributing to myself any particular kind of conscious experience. I'm not claiming to have an image, say, of defeated Democrats, or to hear the word "defeat" ringing in my head. In contrast, if I'm looking at an illusion in a vision science textbook and I say that the top line "appears" longer, I'm not expressing any sort of judgment about the line. I know perfectly well it's not longer. I'm making, instead, it seems, a claim about my phenomenology, my visual experience.

Similarly, although the primary use of "conscious" in contemporary Anglophone philosophy is phenomenological, pertaining to the stream of experience, there's a secondary use of "conscious" in ordinary language that is more epistemic in character, on which to be "conscious" of some fact is more or less just to know it. A child becomes "conscious" of her race, and hippies seek to "raise consciousness" primarily in this epistemic sense. I am epistemically conscious of the time when I'm in a rush, even if I'm not phenomenally conscious of the time during most of my rushing around -- that is, even if I don't often (or even at all) have phenomenally experienced conscious thoughts about the time.

"Awareness" trends the other direction, with the dominant sense being epistemic and the secondary sense phenomenal. If I am aware of something, in the dominant sense, I know it. However, people sometimes use the word "awareness" to refer to the stream of experience, as when Hurlburt asks "What was in your awareness?" as a way of asking about what was being experienced.

Finally, "seems" has an epistemic use very much like "appears", but philosophers sometimes speak of "seemings" with, evidently, the intention to pick out facts about phenomenology.

Not all terms referring to consciousness are ambiguous in this way, but enough are to justify a demand for explanation.

One possibility is that consciousness has an epistemic and phenomenal aspect and these two are intimately tied. Perhaps we are always (epistemically) conscious of our (phenomenal) consciousness (as suggested by Brentano, Rosenthal, Lycan, Kriegel, and others). This might account for the blurring of the two senses in ordinary and philosophical language. Yet it would do so, I think, not in quite the right way: The epistemic/phenomenal ambiguity is not an ambiguity between having experience and being aware of that experience, the two properties that Brentano and company think travel always together. Rather, it's an ambiguity between having experience and being aware of something else, something other than the experience itself, something in the outside world.

My preferred explanation takes "looks" as a clue. "Looks" is, in fact, another term arguably with both an epistemic and phenomenal sense. Blind people use "looks". I can say that it looks bad for the Democrats or that it looks like Helen will get tenure, with no visual implications whatsoever. But, perhaps unlike the other cases, a certain etymological story is very inviting. Here's the story: Because one of the main ways we know about the world is by looking at it, we extend the visual sense of "looks" to cover other cases in which we know about something -- though the explicit reference to how things "look" hints toward the fact that appearances are sometimes misleading. The metaphor then dries out and becomes literal or almost so.

The most salient and dominant form of consciousness is sensory consciousness -- visual experience, auditory experience, tactile experience, etc. -- and when we have sensory experience of something, we generally learn about that thing. I hypothesize that, as with "looks", we metaphorically extend terms referring to sensory consciousness to general epistemic uses, and then these metaphors dry out. We bridge back in the other direction too: Terms for knowledge can start to become terms for sensory consciousness, including in the etymology of "conscious" itself (from "con" together + "sci" knowing).

Philosophers and psychologists sometimes slide between the epistemic and phenomenal senses of these terms -- as, for example, when psychologists unselfconsciously leap from conclusions about awareness in the epistemic sense (can a subject report a stimulus) to conclusions about phenomenal consciousness (was a sensation of that stimulus part of the stream of experience). And those who accept Brentanian or higher-order theories of consciousness, theories that link epistemic awareness and phenomenal conscious tightly together, are cheating if they try to defend their theory by appeal to a dry (and in this case slightly misapplied) metaphor.

Wednesday, October 14, 2009

Review of Structure of Scientific Revolutions in the British Journal for Philosophy of Science

Thomas Kuhn's Structure of Scientific Revolutions is one of the most important works of 20th century philosophy, tranformative in the disciplines of history and philosophy of science. It had a huge impact, in fact, throughout the humanities and social sciences, especially in its use of the idea of scientific "paradigms" -- and probably the current use of "paradigm" in popular culture is at least in part traceable back to Kuhn. The book is also a delightful read. What more could one want as a reader or aspire to as an author?

With that in mind, I enjoyed this nearsighted review of the book in the British Journal for the Philosophy of Science, pointed out to me yesterday by a student. Some quotes:

On reading this book, one's first impression is of enthusiasm and vitality. The author clearly feels himself to be opening up a new world of appreciation and understanding. In the face of such force and charm, it seems mean to question the lasting value of the work; but it must be said that many of its features are already well established (Stopes-Roe, 1964, p. 158).

I would suggest, in fact, that if a reader wishes to bring out the real content of what Kuhn is saying, he may find it advantageous to try substituting ' basic theory' for every occurrence of 'paradigm' in the book. He will come across very few places where the sense suffers (many statements are made about legitimacy and rules, where the content is carried explicitly by an appropriate word); and a careful study of these will be more illuminating than the ubiquitous use of the odd word 'paradigm' (p. 159).
If your wonderful book isn't met at first with universal enthusiasm, take heart!

Tuesday, October 13, 2009

Applying to Graduate School in Philosophy

Yes, it's about that time. Here's a link to a series of posts in 2007 I wrote about applying to Ph.D. programs. All the same advice still applies. Several weeks ago, Robert Schwartz of Milwaukee wrote up this post on applying to M.A. programs.

Wednesday, October 07, 2009

The Transparency of Warped Windows

Gilbert Harman famously wrote:

When Eloise sees a tree before her, the colors she experiences are all experienced as features of the tree and its surroundings. None of them are experienced as intrinsic features of her experience. Nor does she experience any features of anything as intrinsic features of her experiences. And that is true of you too. There is nothing special about Eloise’s visual experience. When you see a tree, you do not experience any features as intrinsic features of your experience. Look at a tree and try to turn your attention to intrinsic features of your visual experience. I predict you will find that the only features there to turn your attention to will be features of the presented tree (1990, p. 667).
Perceptual experience is, Harman says, "transparent": If you try to examine it or attend to it directly, your attention will pass right through it to the features of the outside world presented by that experience. You can attend to the green of the tree, but not to the visual experience of greenness that the light from the tree produces in you, to the cylindricality of its trunk, but not to your visual experience of that cylindricality. Michael Tye, Fred Dretske, Sydney Shoemaker, and others have recently said similar things, and the claim traces back to G.E. Moore (who did not, himself, entirely endorse it). Others, like Charles Siewert and Amy Kind, have challenged such strong claims of transparency.

I've been thinking about the transparency of warped windows. (I feel that I am lifting this analogy from someone, but I don't know who. Siewert? Kind? You? Reminders welcome.) When I look at a tree through a warped window, I might be interested in learning about the tree or I might instead be interested in learning about the window. Now perhaps I can't in a strict sense even see the window. It's not dusty, for example. If so, I can't attend to it visually in quite the same way I can visually attend to the tree; and yet I can in another sense attend to it, in part by attending to the tree. I can notice how warped the tree looks and in what parts, and how that warping changes as I move my head around. Since I know certain things about what trees are like, and especially that they don't noodle around systematically as a move my head, I can discern certain features of the window by looking at the tree. I can know, for example, where it's warped and how badly. Perceptual attention to the tree combines with general knowledge about trees, general knowledge about windows, and proprioceptive knowledge of my own movements and intentions to produce knowledge about the window. Was I, then, attending to the window? It seems to me quite natural to say that there's an important sense in which I was -- even perhaps a perceptual sense.

(Does the fact that general knowledge played into my judgments about the window make it merely "intellectual" attention or inference and not perceptual attention? That seems too strict a requirement on perceptual attention: General knowledge informs my perceptual judgment that the batter is making a run, and even that she's a batter; yet I can attend perceptually to the batter and to the fact that she is now making a run.)

Of course, the window doesn't need to be warped in any way for me to do all this: I might conclude that the window is a perfect, undistorting transmitter.

This perceptual knowledge of the window is in some ways mediated by my perceptual knowledge of the tree. But in other way, it's not mediated. Causally, in the transmission of light, the window is closer to me. I am reacting directly to input conditioned by the window and learning things perceptually about the window on the basis of that input. If the window were different and the tree the same, I would notice that difference; changes in my knowledge of it are not mediated by changes in the outward tree. Are they mediated by changes in my perceptual representation of the tree? Well, what exactly is that representation and where in the visual system? In some sense, I am representing, perceptually, the tree as constant and unchanging. Is there some representation, perhaps "earlier" in the visual system, of the tree as noodling around? Well, maybe -- but if we go early enough we might not have the category "tree" to apply, and there may be no sense in privileging the interpretation of the changing representations as representations of changes in the tree rather than changes in the medium through which light is being transmitted from the tree.

Introspective judgments about perceptual experience often, I think, work similarly and raise a similar tangle of issues. I see something green. I'm not so much interested in learning about the thing in the world as about my experience of it (since I'm a philosopher, or maybe a perceptual psychologist). General knowledge about the world (that there's a green thing there, that lighting conditions are normal) combines with knowledge about my perceptual system (I'm good at seeing green things), combined with proprioceptive knowledge and knowledge of my intentions (my eyes are open, I'm undistracted), to produce the judgment, at least partly perceptual, that I'm having a visual experience of greenness. I look out at night and notice the starburst of light from the lamps; I notice how the lamps' starbursts change when I squint and tilt my head, and can tell in that way that it's a perceptual distortion due to something in me. But that's not all there is to it: There's a responsiveness to my experience that does not depend on what's going on with the lamps. The experience itself, like the window (but even "closer in", as it were) has a direct effect on my judgments about it. It's not purely a matter of perceiving something out there (perhaps erroneously) and then making some abstract inferences.

Or so it seems to me today.

Tuesday, October 06, 2009

The Second Consciousness Online Conference

... call for papers here.