Wednesday, January 30, 2008

You Down With the NCC? No, Not Me.

Seed Magazine, the really entertaining science-themed webzine, posted an article called "Questioning Consciousness" today. It's very thoughtful and well written, and makes an argument quite close to my heart--that we are, for the most part, looking at consciousness in radically incorrect terms, and this conceptual confusion is hindering scientific investigation. However, the author--a philosopher from the London School of Economics by the name of Nicholas Humphrey--proposes several radical ideas about consciousness that, it seems to me, take the discourse in the wrong direction entirely.

The predominant theme of the article is that consciousness is an illusion of sorts, akin to the sort of trickery that goes on when a Penrose Triangle is viewed from certain angles--that is, the "problem" of consciousness is only a problem at all because we're trapped in our subjective first-person jail cells. Snip:

Since the qualia are indeed so up-front and remarkable, and since no one knows why this is, we are all, most probably, going to start off by asking what may be a bad question: "How can we explain the existence of these qualia as we experience them?" So here, again, it will only be if we undergo a radical shift in perspective and realize that the "qualia as we experience them" could be a mental fantasy, that we shall move on to asking what may be the good question: "How can we explain why we have the impression that such fantastic qualia exist even if they do not?" But, here is why it is likely to be so difficult to make this move: In the case of consciousness, we cannot simply change our perspective to see the solution. We are all stuck with the first-person point of view. So, the result is we persist with questing for the qualia as such.

Yet if consciousness is a trick, then of course this quest is a fool's errand. It will make no more sense to try to explain the existence of qualia than it would to explain the existence of the impossible triangle. What we should be doing instead is trying to explain just how we have been set up—and why.

I'm immediately suspicious of accounts that try to eliminatively reduce away consciousness as "illusory" or "not really there." Dan Dennett is notorious for this (he's another one who maintains that qualia don't really exist), as is Paul Churchland. It seems to me that trying to deny that we really are conscious is an exercise in futility, somewhat like Wile E. Coyote thinking that he can keep running off the edge of the cliff so long as he doesn't look down. Indeed, if there's one thing that's defining of humanity, it is the elaborately woven tapestry of conscious states that are open to us. I've read Humphrey's article several times through now, and I still can't even begin to fathom what he could even mean by asserting that consciousness in general--and qualia in particular--is just a "trick of the brain."

I really hate to appeal to Descartes since he was so catastrophically wrong about so many things, but this really does seem to go back to his cogito--if I can be sure of one thing in this universe, it is that I am a conscious and thinking thing. That's what's so unique about cognition, thought, and conscious experience: if it seems to me that I am conscious, then by definition I am conscious of something. The trick is all in the seeming, and that's what Dennett, Churchland, and (apparently) Humphrey seem to miss: even if we're spectacularly wrong about what consciousness is, the fact that we've formed an opinion that can even be right or wrong necessarily entails that we're the sorts of things that can have beliefs, desires, ideas, and opinions--in short, that we are conscious creatures.

Humphrey goes on to pose a few questions about the nature of consciousness that he thinks are only answerable (or at least much more likely to be answerable) if we adopt this position that consciousness is really "nothing special." I'd like to take a moment now to pose a few answers of my own to these questions, answers that don't require us to take the phenomenally (pun fully intended) counter-intuitive step of supposing that my experience when I look at a ripe tomato is nothing more than an illusion (again, whatever that means).

1. What exactly is the real-world brain activity that we are engaging with when we say a sensation is like something?

Who knows, but I would bet dollars to donuts that there isn't just one token activity (or even type of activity) that meets this description; this should be a reflection of how much I believe this to be the case, as I don't even eat donuts (and while I don't eat dollars either, many more merchants accept them as payment). Humphrey (along with many others, Searle included) seems to think that we will one day find the "NCC," or neuronal correlate of consciousness. I'm skeptical that we ever will, but for rather atypical reasons (go figure). I'm not a Mysterian, nor am I any breed of Dualist--that is, I think that we will one day be able to give a scientific account of how consciousness happens, and I think that we live in one and only one world that is composed of and only composed of physical particles. I do, however, reject the computationalist notion that the mind is "modular."

Briefly, this theory says something like the following: the best way to understand the mind is to think of it in terms of modules. We have an "arithmetic module" that lets us add and subtract, a "balance module" that lets us stand upright, and a "consciousness module" that's responsible for our subjective and unitary experience of the world. If we "popped out" the consciousness module, we'd be left with p-zombies, creatures that behave as if they are conscious in every way, but actually lack any sort of subjective experience. As I said, this idea does not ring true to me.

Why not? Before I answer that, I'd like to at least take a stab at answering the other questions posed by Professor Humphrey--in the process of posing these answers, I think I'll probably end up addressing this question as well.

2. Why does this activity have the (tricky) properties it has, such that our experience of it is seemingly something so strangely private, not of this world, and indescribable in common terms?

Once again, who knows! That's an empirical question, and needs to be sorted out by science. We can make a few general statements, though. First, it seems that we can be pretty sure that our consciousness (and thus our qualia) is caused by activity in the brain; I take this to be relatively non-controversial. While some still cling to Dualistic theories of mind we, as modern people of science, can set those theories aside with little chance of error, I think. We can also, I think, safely assert that there is no token/token identity between "mental states" (for lack of better vocabulary) and "brain states"--that is, the brain states causally responsible for my experience of red will not be token identical with the brain states causally responsible for your experience of red, even if we're looking at the same object. This is a very important point, and one that we will come back to.

Additionally, I do object to the notion that our qualia are somehow "otherworldly." What could be more "of this world" than the 'what it is like' quality that conscious experience has? I presume that Humphreys means to say something about the peculiarly subjective nature of qualia, but I don't really see why this nature requires any peculiar explanation--if they didn't have that nature, they wouldn't be qualia at all! In other words, consciousness (at least as we define it) is by definition private, subjective, and "other worldly." No further explanation necessary; once we understand what causes consciousness in general, I suspect that we'll see why it can't be anything but "other worldly."

3. What makes this trick work? How is it done?

A similar answer to the above question--its done through the peculiar arrangement of our neurobiology. If you want a more specific answer, give me a few more PhDs and a few more decades and then ask me again.

4. What is the point? Why was it designed like this? What might have been the evolutionary advantage of our having these marvelous experiences?

John Searle likes to compare consciousness (as a process of the brain) to digestion (as a process of the stomach), and I think this fairly apt analogy can aid us in answering this final question. In the stomach, digestion is a high level process that consists in many lower level processes working toward a common "goal." In light of this, it seems rather silly to say something like "I don't see what the evolutionary advantage of digestion is! It seems that we'd be just as well off with only hydrochloric acid to break food down, bacteria to help us absorb nutrients, saliva to act as an enzyme to begin the process, etc." The reason this statement is silly, of course, is just this: what we've just described is digestion, simply seen from a lower level of description! When we say "stomach acid, intestinal bacteria, saliva, etc.," we aren't enumerating components that are operating independently of digestion, but rather components that constitute digestion. Humphrey writes:

The final challenge will be explaining the biological purpose of all this. We can surely assume that the kind of development I have sketched above will not have happened accidentally. It must be the result of natural selection favoring genes that underwrite the specialized neural circuits—whatever they turn out to be—that do indeed sustain the illusion of qualia, giving rise to the magical mystery show observed by the first-person. And it is axiomatic that this will only have happened if those lucky enough to be spectators of this show have somehow been at an advantage in terms of biological survival. Yet, how can this be if, as is widely assumed by theorists, the phenomenal richness of consciousness is of no practical value whatsoever?

Fodor has stated this aspect of the problem bluntly: "There are several reasons why consciousness is so baffling. For one thing, it seems to be among the chronically unemployed. What mental processes can be performed only because the mind is conscious, and what does consciousness contribute to their performance? As far as anybody knows, anything that our conscious minds can do they could do just as well if they weren't conscious.

Humphrey proposes that the solution to this problem lies in recognizing that:

the role of phenomenal consciousness may not be like this at all. Its role may not be to enable us to do something we could not do otherwise, but rather to encourage us to do something we would not do otherwise: to make us take an interest in things that otherwise would not interest us, or to mind things we otherwise would not mind, or to set ourselves goals we otherwise would not set.
But I don't think this is satisfactory either--the behavior he is speaking of could just as easily manifest in p-zombies; that is, there's no functional difference between a creature that takes interest in and does all the activities Humphrey has in mind because it is conscious, and a creature that still performs the activities, but does so without any sense of a subjective experience. Evolution is the ultimate behaviorist, and doesn't care how (or whether) the behavior is being processed internally--as long as the organism survives to reproduce, it is a success from an evolutionary standpoint.

Instead, I'd like to propose that we have consciousness simply because it is a necessary "add on" that comes for free (loosely speaking) with all the other cognitive machinery we rely on; it is the very fact that we are capable of advanced reasoning, representation, and communication that explains why we have consciousness, and it is the fact that we have consciousness that explains why we are capable of reasoning, representation, and communication. Once again, this view is a rejection of the "modular theory" of the mind--in short, we can't consider consciousness as a faculty in isolation from all the other cognitive faculties we enjoy; while consciousness qua consciousness might not provide any specific evolutionary advantages, our other brain-based abilities most certainly do, and the brain structures responsible for these abilities also are causally responsible for consciousness. I consider this view to be a breed of holism and emergentism both.

A careful reader will no doubt notice that the view I'm articulating here has certain leanings toward epiphenomenalism, and I would like to take a moment to assuage these fears. Epiphenomenalism, you may or may not recall, is a broad family of views claiming that the mind cannot possibly have any causal effect on the body. All mental states are epiphenomena, according to this view, and have an existence something like froth on the tops of waves--the froth (mind) is caused by the waves (body), but doesn't really have any effect on them. I'll admit that my view shares certain aspects with epiphenomenalism (specifically that consciousness is a necessary result of brain chemistry), but there is one vital point on which my view differs. Epiphenomenalism carries within it an implicit endorsement of Dualism: it only makes sense to talk about a causal relationship (or lack thereof) between 'mind' and 'body' if those are two very different things. On my view the mind (consciousness, etc.), like digestion in the stomach, is the necessary, routine, and expected result of the human brain working the way it does; there is a causal relationship between mind and body in just the same sense that there is a causal relationship between stomach acid and digestion--digestion simply describes what it is that the stomach acid is doing.

So, why am I not down with the NCC? Individual minds operate differently. A recent study done at MIT illustrates this point quite well: researchers found that individuals with different cultural backgrounds used their brains radically differently to accomplish the same tasks, with totally different areas of the brain being active and yielding the same functional result. There's no reason to suppose that consciousness, which is the result of the complex interplay between the traits measured in this study, would work any differently--in other words, my 'NCC' might be totally different from your 'NCC,' which effectively means that there is no NCC at all.

This is all a very rough sketch, and the result of a good deal of on-the-fly musing on my part. I fully expect and intend to tighten this down over time. In fact, it seems to me that I've got the makings of a pretty good formal philosophy paper here. Hmm....

Tuesday, January 29, 2008

One Small Step for Yeast...

A few months ago, I wrote a post about the transhumanist movement, and its ideas about extending the human lifespan indefinitely. As I said then, I'm skeptical of this sort of thing--the future course of technology (especially biotechnology) is notoriously difficult to predict, and one of my guiding maxims is "We ought be most skeptical of ideas that we wish to be true;" since never dying (until I want to) sounds pretty damn good, I'm doing my best to be as skeptical as possible about the whole anti-aging research out there. However, I found some new research done by geneticists at USC today that gave me just a little bit of pause.

It's reasonably well known that calorie restriction does indeed seem to increase maximum lifespan in most mammals (as well as other species). However, by combining a calorie restricted diet with a little genetic tinkering (with two genes--RAS2 and SCH9, to be precise), researchers have now increased the lifespan of yeast bacteria by tenfold. Apparently, yeast's aging is controlled by genes that operate in much the same way as genes that control human aging, so the scientists are optimistic about being able to translate this discovery--which could theoretically increase the lifespan of humans to about 800 years--into usable anti-aging treatment in the near future. Snip from the press release:

Researchers have created baker's yeast capable of living to 800 in yeast years without apparent side effects. The basic but important discovery, achieved through a combination of dietary and genetic changes, brings scientists closer to controlling the survival and health of the unit of all living systems: the cell. "We're setting the foundation for reprogramming healthy life," says study leader Valter Longo of the University of Southern California.

Longo's group put baker's yeast on a calorie-restricted diet and knocked out two genes - RAS2 and SCH9 - that promote aging in yeast and cancer in humans.

"We got a 10-fold life span extension that is, I think, the longest one that has ever been achieved in any organism," Longo says. Normal yeast organisms live about a week.

"I would say 10-fold is pretty significant," says Anna McCormick, chief of the genetics and cell biology branch at the National Institute on Aging (NIA) and Longo's program officer. The NIA funds such research in the hope of extending healthy life span in humans through the development of drugs that mimic the life-prolonging techniques used by Longo and others, McCormick adds.

It shall be interesting to see where this goes...

This is Your Brain on the Internet

National Geographic is running a nice little feature on the brain covering neural anatomy in basic, layman friendly terms:

The diencephalon is located in the core of the brain. A complex of structures roughly the size of an apricot, the two major sections are the thalamus and hypothalamus. The thalamus acts as a relay station for incoming nerve impulses from around the body that are then forwarded to the appropriate brain region for processing. The hypothalamus controls hormone secretions from the nearby pituitary gland. These hormones govern growth and instinctual behavior such as eating, drinking, sex, anger, and reproduction. The hypothalamus, for instance, controls when a new mother starts to lactate.

The brain stem, at the organ's base, controls reflexes and crucial, basic life functions such as heart rate, breathing, and blood pressure. It also regulates when you feel sleepy or awake.

The brain is extremely sensitive and delicate, and so requires maximum protection. This is provided by the surrounding skull and three tough membranes called meninges. The spaces between these membranes are filled with fluid that cushions the brain and keeps it from being damaged by contact with the inside of the skull.

They've even got a little interactive do-dad that shows what parts of the brain are primarily stimulated by various activities (e.g. getting tickled, smelling garlic, falling in love). We need more of this sort of thing--the average person knows woefully little about that most vital organ.


Monday, January 21, 2008

Searle Profiled in The Times

It's been a while since I posted here. I've started three or four posts in the interim, but haven't been able to get the momentum going to finish them. I suspect I will eventually. In the mean time, though, today's London Times features a profile of John Searle, one of my teachers at Berkeley and probably my biggest philosophical influence. The author, fellow philosopher Dave Papineau, is pretty balanced in his discussion, both praising Searle for his accessible writing style and devotion to common sense, and criticizing him for some of his more controversial theories (like biological naturalism). Overall, it's a very good article about one of the most celebrated (and controversial) philosophers of the 20th century (or so). The last paragraph is especially good, and neatly summarizes what I like most about Searle:

Still, perhaps Searle’s loyalty to everyday thinking is a price worth paying for his undoubted virtues. During the course of his intellectual lifetime, philosophy has become a dry and technical business. Most philosophers today write only for other philosophers about issues that can accurately be termed scholastic. Against this background, Searle is a beacon of accessible expertise, a throwback to a time when philosophy was part of public debate. His work is devoted to some of the most fundamental questions in philosophy, yet he never gets bogged down in the kind of esoteric disputation that forgets why the issues matter in the first place. If he does this by sticking closely to the firm ground of common sense, this has not prevented him from producing a constant stream of challenging views across a large range of topics. Fortunately, there is no sign of his stopping yet.

Searle, like me, is more or less a proponent of naive realism, which (broadly) dictates that the world in general really is the way it appears to us--think of it as radical anti-skepticism. This common sense defense of reality and the world around us is, I think, what makes Searle such a great thinker.


Friday, January 4, 2008

Congrats to Obama

It seems that Obama swept the Iowan caucus last night, beating Edwards and Clinton rather soundly. Go Barack!

Wednesday, January 2, 2008

Language and Mental Representation

I'm a really big fan of Jeopardy!. I think it's unique among game shows for rewarding quick thinking and verbal cleverness as much (if not more) as brute fact knowledge, but that's not what this post is about. I was watching Jeopardy! last night, and one of the categories was called "Tip of My Tongue." The clues were things like this:

Oh man, this guy...was director of Scientific Studies at the Ecole Normal in 1857....him-"ization" me out here..

This reminded me of a conversation I had a week or two ago with a friend of mine (the answer is Louis Pasteur, by the way); we were discussing theories of representation (i.e. how it comes to be the case that 'cat' refers to something furry and hungry in the real world), and I put forward the idea that perhaps we cannot put forward any truly "universal" theory of reference, because how words (and other symbols) come to refer might vary based on individual neurological idiosyncrasies. She agreed, pointing out that when a name or word is on the "tip of her tongue," she tries to remember it by thinking about what the word feels like to write or say, whereas I think about the concepts connected to that name or word (much like the clue above).

While this certainly isn't indicative itself about how words refer to each of us, I think it does speak to an often overlooked fact--namely, that while our brains end up getting the job done, they often do the job in radically different ways. Just looking at the simple (and common) "tip of the tongue" phenomenon shows how differently we humans can process the world; it seems at least plausible to me that given these variations, fundamental cognitive activities (like reference and the creation of meaning) might happen in very different ways for different individuals.

What do you think of this? What is the "tip of the tongue" phenomenon like for you?