Wednesday, January 30, 2008

The Richness of Experience and the Collapse of Consciousness Studies

Many people have looked foolish by claiming a scientific question insoluble that was not so. Yet I wonder if the following question will prove ultimately intractible: Is conscious experience rich or thin?

To say that consciousness is rich is to say that our phenomenology or stream of experience contains many things at once, in different modalities -- that as I sit here typing for example, I consciously experience not just what I'm attending to most focally, but also much else in a peripheral way: the sound of traffic in the background and of click of the keys on the keyboard, the feeling of my fingers typing and of my feet in my shoes and of my back against the seat, a whole broad visual field fuzzy outside the focal region, and possibly also feelings, images, inner speech, and the like. To say that consciousness is thin is to say that most of what we don't attend to we don't experience. The feeling of my feet in my shoes and the sound of traffic in the backgroud are not actually experienced by me, not even in a peripheral way, when I'm not thinking about such matters.

Philosophers' and ordinary folks' intuitions on this question appear to be divided; and I also got mixed results when I gave people random beepers set at long intervals and asked them to go about their ordinary day, noticing when the beep went off whether they had (for example) tactile experience in their left foot in the last undisturbed moment before the beep.

The refrigerator light illusion frustrates any attempt to address this question through concurrent introspection: Thinking about whether you have conscious experience of your feet in your shoes will normally create that experience whether it was there before the question occurred to you or not.

So it seems that the question must be studied retrospectively (as I attempted with the help of the beeper). But any retrospective study will raise the issue of memory error. Change blindness studies, for example, suggest that we retain very little memory of what we're not attending to, even over the tiniest intervals. Experience could be massively rich but all that detail might be instantly forgotten. (Why, after all, would we retain it?) Some people may still recall a general impression of richness; but evidently others do not. Who's to say which of them is right? Furthermore, someone might mistakenly report sensory details as experienced that were not experienced, but only called to mind as a result of the beep, details brought into awareness as a result of the person's focus a moment later, though not experienced at the targeted time -- a kind of retrospective refrigerator light error. I worry that such introspective difficulties are intractable.

So could we do without introspective report? Could we just look at the brain, for example? No, not that either. We have no good theory right now of what makes a brain state conscious; and we never will have a good theory until we know, broadly speaking, which brain states are the conscious ones; and we will never know, not even broadly speaking, which brain states are the conscious ones until we figure out whether that hum of traffic processed ever so lightly in the auditory cortex is consciously experienced.

So is the question simply intractible? If so, that could lead to the collapse of consciousness studies. The question is so central and important to our understanding of consciousness that it's not clear how much progress we can make on any general account of consciousness without resolving it.

Monday, January 28, 2008

"Toys R Us". Are They Us?

Four-year-olds can communicate somewhat complex ideas, but their minds are still alien; their language hasn't quite settled down into adult patterns; and they're flying by the seat of their pants socially. I'd love to see a site devoted simply to the interesting things they say!

Those interesting things are so easy to forget. Our memories tend to reshape and adultify in retelling; we can't hang on to the weirdness. I wish Pauline and I had done a better job capturing Davy's interesting remarks as a four-year-old; but we do have a few (what we think of as) gems. I hope readers will contribute their own in the comments if they have any!

In a restaurant: "It smells like a rainbow of things to eat" (4 yrs, 0 months).

"Mommy, you're evil, so I taked away your shoe" (4 yrs, 0 months).

Davy's great grandmother died. We took him to see the body. He wanted to touch it to see "if she's still squishy but doesn't move" (4-0).

"I wasn't being bossy. I was being right" (4-1).

At bathtime: "I hate to hide from you, but it's just a special occasion" (4-1).

"Is it today or tonight?" (4-2).

Of a new toy truck: "It springed my heart with love, I like it so much" (4-2).

Arguing about who has the better mommy:
Mary Travis: My mommy can help anyone!
Davy: My mommy can help anyone!
Mary Travis: My mommy can talk to anyone!
Davy: My mommy can talk to anyone!
Evidently this is what mommies do: help and talk (4-4).

Daddy: Are you fine?
Davy: I'm so fine I could burst a porcupine! (4-4)

Davy: Jesus didn't have a crib.
Daddy: What? Oh, right. "No crib for a bed."
Davy: I don't have a crib.
Daddy: So you're Jesus.
Davy: Yes. No! (4-4)

"Maybe they call it 'Christmas' because you MISS it and... and... and it's Chris" (4-5).

"My race car is fun-fastic!" (4-5).

To Mommy: "I said 'Wonka Nerds' because my brain took a peek at it before I did. My brain is very smart because it looks at things before I do and it discovers things before I do and that's why I'm smarter than you" (4-6).

Davy punches Mommy.
Mommy: Don't do that. That hurt!
Davy: Did it sting?
Mommy: I'm not saying.
Davy: Did it sting?
Mommy: I'm not telling you so you can enjoy it.
Davy: I enjoy punching people.
Mommy: Well I hope no one punches you and enjoys it.
Davy: I like to be punched. I didn't like it when I was a baby but I absent-mindedly got used to it (4-6).

Davy sneezes. Mommy usually says "bless you", but she's on the phone and ignores it. Davy says, "bless myself" (4-7).

Davy: I don't need a diaper. I just insulated myself for sleep.
Mommy: Insulated yourself?
Davy pulls up his shirt to reveal wads of toilet paper stuffed into his pants (4-7).

"All my ideas live here [points to tummy]. Then they come up to my brain and I think them" (4-8).

Davy: Maybe this is a dream.
Daddy: This, right now?
Davy: Well, maybe. If this hurts. [He pulls on Daddy's earlobes.] (4-11)

Davy: Mom, what's smaller than the smallest thing in the whole world?
Mommy: What? No, there can't be anything smaller than the smallest thing in the whole world.
Davy: No, I don't know what it is, but it's the smallest thing in the whole galaxy! (4-11)

Well, I can't quite resist going a bit into the fives:

"You know why I win [marbles] all the time? Because my blood cells have little actions spirits ready to win" (5-0).

Daddy: Nothing goes faster than light.
Davy: No, something does.
Daddy: What?
Davy: Something that doesn't exist (5-0).

Daddy: If I spin a 3 [in Chutes and Ladders] I win!
Davy: You're not going to spin a 3!
Daddy: How do you know? Precognition? Psychic powers?
Davy: Extra strong brain! (5-0)

"You can't grab afterimages. When you grab them you just get air. Nothing made me think of that. It just popped into my brain" (5-0).

Seeing our brand-new minivan for the first time: "Hubcaps shiny as the sun! Tires as sticky as a sticky-frog!" (5-2).

Looking at the toy store sign: "'Toys R Us'. Are they us?" (5-2).

Friday, January 25, 2008

Consciousness While Reading -- Is It Visual? Imagistic? Auditory?

Some people say they speak silently to themselves when they read; others say they don't do that, but do entertain visual imagery. Others claim to do neither but rather only to see the page and take it in. Melanie, whom Russ Hurlburt and I interviewed at length in our recent book about conscious experience, reports no visual experience of the written page at all; rather, she experiences only the images, thoughts, and emotions that the text creates in her. (No visual experience of the page whatsoever? Wow, that's hard for me to imagine!)

Maybe people are very different in how they experience reading. If so, I know of no systematic studies. (Of course there are plenty of studies of differences in reading skill, in the use of the eyes on the page, on the sorts of errors people make, etc., but that's quite different.) If there is such variation, it could potentially be very useful to reading teachers (and poets?) to take advantage of it.

Or maybe people differ mainly in their reports about how they read, while their experiences are all very broadly speaking the same. (We do have, I think, false general impressions about our stream of experience quite often.) So it would be neat, before going too far out on a limb here, to get some external corroboration for the reports.

It's easy to think up cute experiments:

* People who speak silently to themselves while reading would tend, I'd think, to have strong impressions about how to pronounce unusual names they find in the text (it's GOLL-um, dammit, not GOAL-um!); people who are more strictly imagers may not. Experimenters could pronounce a name in an unusual way and measure (a) likelihood of being corrected by the subject, (b) skin conductance (a measure of stress), or (c) attentional blink (poor performance on an immediately subsequent task).

* People who say they hear the text aloud sometimes claim to hear it mostly in their own voice; others claim to hear the author's (imagined) voice or the characters' voices. The latter sort of reader, but not the former, may show additional facility or impairment when an external voice or sound is presented that matches or mismatches the characteristics of the author's or characters' voices.

* People who visually experience the page may have better memory for visual details of the text than people who do not.


If the results of such measures align neatly with people's self-reports, great! There may really be a phenomenon here worth studying.

So many experiments, so little time!

Wednesday, January 23, 2008

Bertrand Russell on the Philosopher's Temperament

The curmudgeonly essays Bertrand Russell wrote late in life generally get little attention from philosophers -- strikingly little, really, given that he was such a famous philosopher. For example, in the (admittedly limited) ISI Web of Knowledge citation database, I see only nine citations since 2000 of Russell's book Unpopular Essays, and none in mainstream philosophy journals.

I, however, am enjoying the essays, at least in my present also somewhat curmudgeonly mood -- though they do sometimes display the intellectual laziness common to grand old men who know they won't have to fight their way through unsympathetic referees to find print. (Hm, come to think of it, blogs are a little like that, too!)

One passage that particularly struck me, given my growing interest in the psychology of philosophy, was this:

Philosophy has been defined as "an unusually obstinate attempt to think clearly"; I should define it rather an "an unusually ingenious attempt to think fallaciously". The philosopher's temperament is rare, because it has to combine two somewhat conflicting characteristics: on the one hand a strong desire to believe some general proposition about the universe or human life; on the other hand, inability to believe contentedly except on what appear to be intellectual grounds. The more profound the philosopher, the more intricate and subtle must his fallacies be in order to produce in him the desired state of intellectual acquiescence. That is why philosophy is obscure.
Russell illustrates this point very plausibly with the Descartes of the later Meditations, where Descartes attempts to reason his way out of his skeptical quandary by proving the existence of God. Russell also offers Berkeley, Kant, and Hegel as examples, though Russell's treatment of the latter two especially will strike any sympathetic historian of philosophy as irritatingly simplistic. Being myself generally an unsympathetic historian of philosophy, though, I wonder if Russell hasn't simply cut through the bullshit and seen the core. Here he is on Hegel:
Hegel's system satisfied the instincts of philosophers more fully than any of its predecessors. It was so obscure that no amateurs could hope to understand it. It was optimistic, since history is a progress in the unfolding of the Absolute Idea. It showed that the philosopher, sitting in his study considering abstract ideas, can know more about the real world than the statesman or the historian or the man of science.
Given that our attraction to or revulsion from philosophical ideas tends to far precede our understanding of the subtle arguments pro and con (as I discussed a bit here), I suspect Russell is correct that such psychological considerations are a major factor driving both individual philosophers and the discipline as a whole, despite our flattering self-image.

This also makes me wonder whether Russell's late-in-life History of Western Philosophy has more to it than historians generally give it credit for.

Monday, January 21, 2008

The Rule of Three

In connection with Vincent Hendricks's recent advice on increasing one's visibility in academic philosophy and the subsequent discussion at Thoughts, Arguments, and Rants, I thought I'd post some of my recent thoughts on academic memory -- what I'll call the "rule of three".

Here's the rule of three: If you devote cognitive attention to an academic matter only once, you will retain no functional memory of it. If you devote attention to that matter twice, you will recognize it vaguely when you encounter it again, but you won't freely recall it. If you devote attention three times, you will be able to freely recall one thing about it.

This works, I think, in the classroom: If a student reads a philosopher, then hears a lecture about that philosopher, then finally studies that philosopher again for the final exam, she will be able for some time afterward to remember some core thing about that philosopher. If she does only two of the above, she will recognize the philosopher vaguely when the name is presented. If she does only one of those things, nothing useful will be retained.

It also works (more to the present point) in the context of getting to know a fellow philosopher. Based on my own experience: If I have no previous acquaintance with a philosopher (through her work or otherwise) and I have a conversation with her at a conference from which nothing further comes, I will not recognize her the next time I see her. If I do this twice, I will have a vague recollection next time I see her. Three times, though, and I'll remember who she is and probably one key fact about her. I suspect many other academics' memories work the same way. Sometimes, a person gets a two-fer or a three-fer in my cognitive space: If the conversation was striking enough that I return to it later in my mind in some extended way, then that's two instances of attention; if we then follow it up with an exchange of interesting emails (for example), that's three instances.

This principle also applies to presentations and publications. If something I hear or read only once is striking enough, or close enough to my current perplexities, that I think about it for some period of time on at least three separate occasions, I will retain the main idea of it (or what seems to me the most important or useful idea given my interests) for a while. However, most work -- especially conference presentations -- regardless of how assiduously I take notes at the time, doesn't command enough of my interest that I return to it seriously later, and consequently a single presentation of the ideas won't stick. It takes some repetition. If I hear it in a presentation, then we chat about it afterward, then I see the published essay, it will stick with me even if I wasn't much enamored of it. The nature and order of these events doesn't matter much: It might be three journal articles (oh, that's the guy who keeps saying the HOT theory of consciousness has flaw X), or three conversations, or two criticisms of the work by other philosophers followed months later by an oral presentation by the author himself, or whatever.

Now of course this rule isn't hard and fast, and what exactly qualifies as an episode of "cognitive attention" is pretty fuzzy (I mean more than seeing the name cited and less than reading an entire book by the person) -- but the implications for improving one's academic visibility (if that's one's aim) should be clear: Go to the same conferences, publish on the same topics, expose yourself to the same people, multiple times -- don't spread yourself thin. And since you shouldn't expect people to retain more than a single core fact about you unless they're exposed to you more than three times, try to have a consistent theme or idea or topic in your work, especially earlier in your career. Something of intermediate specificity is probably best ("consciousness" is too broad, "problems with Schnerdfoot's reply to Huberdike" is too narrow).

Of course maximizing academic visibility may not be your only aim! I often spread myself too thin, from a career-maximizing perspective, from sheer enthusiasm on too many topics.

Friday, January 18, 2008

Call for Papers: Special Journal Issue on Experimental Philosophy

"Psychology and Experimental Philosophy" E. Machery, T. Lombrozo & J. Knobe (eds.)

European Review of Philosophy, 9 (2009)

Submission deadline: 1 September 2008

Details here.

Color and Dream Experience in Philosophy, 1940-1959

As regular visitors to this blog may recall, I've occasionally discussed a historical trend in reports of the coloration of dreaming -- a tendency for Americans (that is, residents of the U.S.) to report overwhelmingly black-and-white dreaming in the 1940s and 1950s, and a tendency for pre-20th century philosophers and psychologists and 21st century Americans to report predominantly or exclusively color dreaming. With Changbing Huang and Yifeng Zhou, I found the same trend in subgroups in mainland China, where rates of reporting of black-and-white dreaming varied with the prevalence of black-and-white media in one's community. My hypothesis is not that the actual content of the dreams changed between these periods. (For example, rates of color-term use in dream diaries are amazingly consistent.) Rather, I hold that it was only the reporting that changed -- more specifically, that at least some people mistakenly assimilated the properties of film media to their dream experience.

Recently I've been wondering if I'd see the same trend among philosophers. Would philosophers of the 1940s and 1950s say that dreams were mainly black and white? This issue is especially interesting in the context of dream skepticism, the view (from the ancient Chinese philosopher Zhuangzi and from Descartes's first two Meditations and from many other sources) that we cannot, or cannot reliably, discriminate between dream experience and waking sensory experience. If waking visual sensory experience is pervasively colored and while dreams rarely contain colored objects, both of which many Americans in the 1940s and 1950s would have granted, it should be easy to tell the one from the other, right? So dream skepticism should be less compelling.

So far, however, in looking through the literature from that period, that's not what I've found. On the contrary, the issue doesn't even seem to arise in the literature on dreams and dream skepticism (though I still need to check more sources to say this definitively). Some philosophers even casually mention color as an element of dreams, without special remark or acknowledgement of the issue. Elizabeth H. Wolgast, for example, when reaching for an example of a dream in the context of a discussion of dream experience and waking sensory experience, imagines someone saying, "In my dream, I saw great blue grasshoppers" (Philosophical Review, 1958, p. 231). She does not remark in particular on the issue of coloration.

I'm not sure how much to draw from this. Even in the black-and-whitest days of black-and-white dream reporting, people tended to acknowledge the possibility, at least, of fully colored dreaming. And maybe that possibility is enough for philosophers to do their thing, and to justify dream skepticism to whatever extent it is justified?

Wednesday, January 16, 2008

Rationalizing Emotions and The Moral Behavior of Kantians

I've recently been enjoying Joshua Greene's "The Secret Joke of Kant's Soul" (penultimate manuscript available here). Greene's research suggests that the moral judgments of Kantian deontologists (who focus on such things as rights, duties, and "respect for persons") tend largely to be rationalizations of evolutionarily-selected emotional responses, while the moral judgments of utilitarians and consequentialists (who focus on such things as maximizing the good of everyone) tend to be more rationally driven (or at least less driven by emotional "alarm systems"). The sorts of cases on which Kantians and consequentialists tend to disagree are cases where maximizing the good violates what we might perceive as someone's rights. Should you push someone in front of a runaway trolley, thereby killing him, if that's the only way to save five other innocent people? Should you smother your baby to death if that's the only way to prevent yourself, your baby, and several other people from being found and killed by Nazis? The Kantian impulse (with caveats and complications, of course) is to say no in such cases, the consequentialist to say yes.

Now if (a.) Greene is right about Kantianism as principally a post-hoc rationalization of evolutionarily selected emotions -- and needless to say it's very controversial! -- and if (b.) the apparently widespread view is correct that Kantians behave less well than consequentialists, and finally if (c.) emotional reactions tend to be more self-serving than do consequentialist principles, then, well, maybe (a) and (c) together explain (b).

Let me stress that I myself have no beef against Kantian deontology or Kantian deontologists and that conditions (a) and (b) are highly speculative. Finally, the only small bit of direct empirical evidence I have on the moral behavior of Kantians versus deontologists (the rate at which ethics books are missing from academic libraries) suggests that patrons are no more likely, and maybe even a bit less likely, to misappropriate Kantian than utilitarian texts.

Tuesday, January 15, 2008

Updated Photo

Here's my principle: If your photo on the web is more than ten years old, you're either lazy or vain. (Well, Genius may be an exception!) Fancying myself neither and flirting with the ten-year mark, I've finally been forced to update.

Ah well. At least I'm already married!

Monday, January 14, 2008

Peripheral Vision: Mapping Color onto Shape

It's well established in vision science that perception of shape and color declines precipitously outside the central one or two degrees of visual arc (about the size of your thumbnail held at arm's length). Most people find it surprising, actually, how poor their peripheral vision is, and how narrow the region of clarity (despite the number of hours each of us has logged expertly seeing outward things). Dennett's playing card experiment is a nice way to test yourself: Take a playing card from a normal deck, without looking at it. Hold it at arm's length to one side, just beyond the field of view. Keeping your eyes fixed on a single point ahead of you, slowly rotate the card toward the center, noting when you can discern its color, its suit, and its value. It won't be until almost dead center that you'll be able to tell if it's a Jack or a King.

But if shape and color perception are bad individually in the periphery, Peter Neri and Dennis M. Levi (2006) suggest that things are even worse when you combine them.

Suppose you are presented a red square and a blue circle. Regions of your brain specializing in color will register a red thing and a blue thing. Other regions specializing in shape will register a square and a circle. If everything works right, you'll also know that it's the square that's red and the circle that's blue -- but that is a bit of extra work, an additional thing that must go right. In some situations, people will get the colors and shapes right, but they won't know which color went with which shape (Triesman and Schmidt 1982).

Neri and Levi's experiments suggest that this sort of "feature binding" goes especially badly in the periphery. Even at resolutions where their subjects could make out color and shape individually, they could not accurately put those colors and shapes together.

Now I have some picky complaints about the methodology of their experiment -- having to do with Gestalt principles for shape detection and possible single-feature computing shortcuts (if you go to their article, note the "7"-like figure in the left hand image in Fig. 1C which could not occur in a non-target image; HT: Ryan Robart) -- but there's also the phenomenological question. Peripheral vision seems blurry, and the color of unknown objects can be surprisingly indistinct or inaccurate, but does it additionally seem on introspection that the colors out there get mapped onto the wrong objects, or that the colors and shapes don't coherently fit together?

Billock and Tsou (2003) describe the phenomenology of binding failure thus:

In other cases, all sense of object and surface can be lost and the target is perceived as a ‘jumble of lines’ or ‘extremely confusing and hard to describe’. Moreover, the contrast of equiluminant images can seem unstable – Gregory describes such images as ‘jazzy’. In 1927, Liebmann reported that there is a ‘critical zone [where] everything flows…glimmers…most everything is soft, jelly-like, colloidal. Often…parts which belong together in the normal figure now have nothing to do with one another. [It is] a world without firm things, without solidity.’
Is that how peripheral vision seems? I've been walking around today trying to notice, and it just doesn't strike me that way. Indistinct, yes. But binding failure is different.

Furthermore, I've finally found a use for all those silly business cards they gave me when I was promoted to Associate Professor. On the backs, I've written letters and shapes right next to each other in arbitrary colors. I made about 80 cards, each holding two of eight shapes in two of four possible colors. Rotating them in from the periphery, I don't find myself making many binding errors. As soon as the cards are clear enough to distinguish shape and color, I know which shape goes with which color.

Friday, January 11, 2008

Book Review

Readers of this blog might be interested to see this review, in Salon, of my recent book with Russ Hurlburt, Describing Inner Experience? Proponent Meets Skeptic.

I'd love to say something clever about the review, but I've never been much good at clever. (Maybe that's part of what helps keep me "straight-faced"?)

Wednesday, January 09, 2008

Inner Speech, Imageless Thought, and Bilinguality

In our book Describing Inner Experience?, Russ Hurlburt suggests that people often overestimate the amount of inner speech (silent speaking to oneself) in their stream of experience. People, he says, simply presuppose that that is how thinking must occur. What the basis of this presupposition might be, Hurlburt doesn't explain, but I suspect our opinions about our minds are often shaped by analogies to media and technology (e.g., computers [or in the old days, clockwork] for minds in general, movies for dreams, pictures for vision). Maybe we can think of language as a medium or technology particularly apt for analogizing to thought.

In conversation Hurlburt has also suggested that one basis for the impression many people have that they frequently or constantly talk silently to themselves is that when we stop to think about what our current stream of experience is, that self-reflective activity tends itself to produce inner speech in many people. Why exactly this should be so I'm not sure. But if it is so, someone might gain the false impression that inner speech is constant because she notices inner speech whenever she stops to think about what her experience is. (This would be a version of the "refrigerator light error".)

Hurlburt goes into considerable detail in our book (in Ch. 11) defending the idea that much conscious thinking takes place neither in speech, nor in images, nor in any other symbolic format. He calls this "unsymbolized thinking" and describes the resistance many people have to this idea. (It is in fact a matter of controversy right now among philosophers such as Charles Siewert, William Robinson, and David Pitt.)

I was then surprised a couple weeks ago, when chatting with a brother in law about his stream of experience, when he casually said -- as though it were the most obvious thing -- that he just had a thought that was quite conscious but neither spoken nor in any imagistic form. When I asked him how he knew that he thought was imageless in this way, he said that it had a specific content but nothing visual, more like words, but actually lacking words, since it was neither in English nor in Hindi.

I was then struck by the following idea: Might bilingual people -- really bilingual people who shift easily and regularly between two languages -- more easily recognize unsymbolized or imageless thought than monolingual people? A monolingual English speaker might experience a thought content and then falsely assume that the thought must have taken place in English. A bilingual person, forced to think about what language the thought transpired in, might in some cases find no basis for choice and so more readily recognize the non-lingustic nature of that thought.

Your thoughts are welcome -- but please translate them into some linguistic format (preferably English) first!

Monday, January 07, 2008

How I Know I'm Not Dreaming (I Think)

I'm not dreaming. Neither are you.

Oddly, the second sentence seems to be self-confirming in a way the first isn't -- if it refers to an actual "you", that is, if anyone other than me actually reads the sentence, then the sentence must necessarily be true (barring paranormal dreamer-to-dreamer communication). But of course this doesn't imply that I have any special knowledge of your waking state. It's merely a trick of language....

How do I know I'm awake? Responders to the previous post, and others I've questioned, tend to offer the following grounds for knowing:

(1.) Sensory experience is more vivid or detailed in waking than in dreaming. The pinch test may be a version of this. Some claim not to feel their feet on the floor or to be pained staring at the sun. Others say the wide panoply of current visual experience would be impossible in sleep. (Jonathan Ichikawa has recently been arguing that it's not even sensory-like experience we have in dreaming but rather only imagery.)

(2.) Sensory experience is more stable and organized in waking than in dreaming. Some people, for example, say that the words on a page (or on a computer screen!) won't stay still during dreaming, or that a clock's time will be strange or blank or keep changing.

(3.) I cannot do some actions that I can ordinarily do when I try to do them while dreaming -- for example, I can't fly.

Now, I'm inclined to dismiss (3). Maybe, if I can fly, I can rightly conclude that I am dreaming, but the reverse doesn't seem to follow. I suspect that it's perfectly normal to have dreams in which one cannot fly, etc., even if one wants to (unless, perhaps, one realizes one is dreaming and so takes command of the dream, as in lucid dreaming).

(1) and (2) are more tempting. In fact, when I started planning this post I thought I might go for a version of (1). But here's my problem: I go to a quiet place and close my eyes. I still feel quite confident I'm awake. But my visual experience is not very distinct or organized -- certainly not so distinct and organized that I couldn't imagine my brain producing just such experience during sleep without the aid of external input. My auditory experience is pretty vague and thin too. I feel my feet on the floor, of course. But could it really come down to such a slender thread? Is that really my only basis for knowing I'm awake? What if I found a way to deprive myself of vivid or organized tactile sensation too (e.g., by floating in water)? Would I then have no basis for knowing whether I'm asleep or awake?

So maybe we should consider:

(4.) There's some direct and intrinsic knowledge we all have when we're awake that we're awake -- knowledge that's somehow immediate, not on the basis of anything sensory or quasi-sensory.

I point out that accepting some version of (4) -- or (1) or (2) -- does not imply that I can always know that I'm dreaming when I am dreaming. In dreams, we are often confused and leap to weird conclusions. This fact no more undermines my coherent, unconfused present knowledge of my wakefulness than the fact that a deluded, confused person might mistakenly think he's a philosophy professor undermines my non-deluded, non-confused knowledge that I'm a philosophy professor. Our opinions are differently grounded.

Now I wonder where in the philosophical or psychological literature we can find someone who develops an idea like (4). No one comes to immediately to mind, but surely there's someone....