There is no knock-down Theory of Consciousness here. Instead, I have put some stakes in the ground, arguing in these essays for some things that I think must be true, and for other things that I think are probably true. I have tried to make some clarifying distinctions and come up with useful ways of thinking about some of the issues surrounding the topic of consciousness. I have also tried to suggest some things we should be thinking about and ways we should be thinking about them to clarify things further.
I am, it must be admitted up front, sceptical of philosophy. It is a cliche that all philosophy can be dismissed with the accusation, "But that's just playing with words!" As with many cliches, there is a grain of truth here.
Too much of philosophy (Anglo-American philosophy, anyway) falls into the language trap. Philosophers often seem to have a deep-seated belief that our words reflect very precise and distinct ideas, and if we just think hard enough, we can define our terms exactly, so that there will be no fuzzy borderline cases. Philosophy is about the study and construction of formalisms, articulations of ideas using language, but language is a tease. It seems to have rules and structure, but this is often something of a mirage. It is infinitely plastic, and any attempts to achieve absolute precision by defining words in terms of other words is a fool's errand. Language will laugh and run just ahead of you, and you will chase it further into the thicket. All language is folk language, and if you are obsessed with stating things absolutely precisely, you can always find ambiguities and potential contradictions in even the most seemingly unproblematic statements. You can chase your tail forever tracking down all these ambiguities and contradictions. This is why so much of philosophy degenerates into navel-gazing, while physics, for example, does not. I would rather learn new things than invent perfectly precise ways of talking about things everyone already knows.
It is perfectly fine, for example, to say, "would you please pass me that salt shaker," without defining exactly what you mean by "salt shaker". Would a bowl filled with salt count as a salt shaker? Would it count as one in a culture where the accepted method of using the bowl to salt your food was to shake (not spoon) the salt from the bowl over your plate? Is a doll's house salt shaker a salt shaker, even though it can never work as an actual dispenser of salt? These are annoying questions - just pass me the salt! It doesn't matter whether we have an absolutely precise definition of the term "salt shaker", because in the context in which I am using it, my meaning is unambiguous. Sometimes philosophers like to point out, with elaborate hypothetical scenarios, that a certain term has some fuzzy borders, and thereby conclude that we can say nothing at all using the term until we clarify it - "I refuse to even consider your request that I pass you the salt shaker, because you can't define your terms. Tell me exactly what is and is not a salt shaker, and then we can talk." This is sometimes overplayed to the point of eyeroll-inducing pedantry.
The counter-argument to this warning about philosophy is that there are times when people are much too casual about their use of certain words. It is tricky, especially when doing philosophy, to know how precisely you should define your terms, given your use of them. In general, the more weight you expect your terms to bear, the more carefully you should define them. If you are going to say very broad, sweeping things, and make universal declarations, you had better be prepared to defend the terms you use in a fair amount of detail. If you say, for example, that the universe is just a giant computer, or that all of physics comes down to information processing, you better describe exactly what you mean by "computer" or "information" so that your statement is both arguably true, and that it also does not slide into vacuity.
In the following essays, I may, at times, seem to be edging toward the aforementioned eyeroll-inducing pedantry. When I do this, it is because I want to distinguish between real things, and may-be-seen-as things. There are some things which are really, really there. An electron is really there. It obeys electron laws, and Nature treats it differently than it does photons or quarks. Moreover, an electron will behave in its unique electron way whether you think of it in the right way or not, and even if there is no one around to think of it in any way whatsoever.
But there are other things that are merely really there for certain purposes, or may be seen as really there (depending on how you look at them), or there in the sense that certain other things that are really, really there may be seen as examples of those things when abstracted in just the right way. For example, the salt shaker is really just a certain conglomeration of molecules, that for our purposes, for our cognitive convenience, we find useful to call a salt shaker. But Nature does not know this. The object you and I agree to call a salt shaker is made of components that obey the same laws that they would if no one thought of it as a salt shaker, or even if there were no one around to think of it one way or another. There are no special salt shaker laws of Nature or properties of being that come into play suddenly as soon as some conglomeration of molecules is seen as a salt shaker, or could be seen as a salt shaker by a hypothetical observer.
Imagine that someone told you that they had figured out a new law of physics: that all salt shakers have a slightly greater mass than they "should" have, simply by virtue of their being salt shakers. You might find yourself asking some of those pedantic philosopher questions: how could Nature possibly "know" that the salt shaker is a salt shaker? As you start making a salt shaker, at what point does Nature start regarding it as such and increase its mass accordingly? After asking some of these questions, you would rightly conclude that your friend's new law was silly, and that the distinction between salt shakers and non-salt shakers was not a natural distinction. This is not to say that salt shakers don't exist, or that it is somehow wrong to think of a salt shaker as a salt shaker, but only to say that its status as a salt shaker buys it nothing in the eyes of Nature above and beyond the tried and true laws that apply to all the other non-salt shaker objects. There is no special property of salt shaker-ness that Nature is bound to respect.
Another problem with philosophy is the tendency to build castles in the air. Philosophy is a lot like mathematics, in a way. A philosopher is free to define his terms any way he wants on the basis of pretheoretical assumptions, intuitions, common colloquial usage, or just plain whim. Then he is free to write hundreds of pages building on these definitions, proving all kinds of things on the basis of that definition. Naturally, each philosopher likes to define his terms according to the lights of his own particular reason. A philosopher would rather use another philosopher's toothbrush than use his terminology, as the saying goes.
As an Anglo-American philosopher, I am a wannabe scientist (as opposed to the Continental philosophers, who are wannabe poets). I want to isolate the really-there things in the universe, as opposed to the may-be-seen-as things. I want to define my terms in such a way that I can focus my attention on those things that constitute actual unique phenomena in the universe, like electrons. A great deal of philosophy, particularly epistemology, consists of investigation into the properties and implications of things that either just don't exist, or don't necessarily exist in a fundamental, really-there kind of way, but instead are more like the salt shaker. For example, there are lots of books and journal articles about the nature of knowledge and belief, and these are loaded with definitions of knowledge in terms of belief (knowledge is true justified belief, etc.). But what is a belief? The epistemologists have an answer for that. Lots of answers. But the definitions of things like "belief" tend to sound like mathematical or logical definitions, something people might have come up with a couple of hundred years ago during the Enlightenment.
I suspect that it is a mistake to assume, for example, that there is a perfect, Platonic, mathematical/logical definition of "belief". Of course, any philosopher is free to define "belief" any way they want, but any conclusions they reach thereby will not necessarily have any explanatory power in the real world. Rather, I think we ought to study things like belief naturalistically: first, we start by listing all the reasons we have for thinking that there is any such thing as belief in the first place. Then we should look for the most elegant, parsimonious explanation for the phenomena on that list. In the end, I suspect that we will end up defining "belief" in terms that sound much more psychological than most practicing epistemologists are comfortable with. Our notion of "belief" will end up being a product of the cognitive architecture of the mind, and not something that lends itself to a neat, crystaline defintion.
The point here is that, given the choice between respecting our pretheoretical intuitions and folk usage on one hand, and redefining terms in such a way that we end up respecting natural distinctions on the other, I will usually opt for the latter course. Once we figure out what is really going on in the world, the intuitive pull of the neat, crystaline definitions will melt away.
Someday the questions about the mind will be answered, and those answers will be summarized in a chapter or two in an undergraduate textbook, right after the chapters about quantum mechanics and relativity (or perhaps right after chapters about DNA or something). This is going to be a science. It has to be philosophy right now, because we have so little to go on. This is the function philosophy has served throughout the ages: as the incubator for other, more specific fields of inquiry. All of the hard sciences (and the soft ones too, for that matter) were once considered philosophy: biology, botany, psychology, sociology, to name a very few. Once people get their hands on a few basic principles in a branch of philosophy, it can be spun off as its own freestanding field. Consciousness studies, then, is just passing through philosophy on its way to real science.
Laboratory results are great, indispensable even, but the current impasse will only be resolved by a conceptual breakthrough, a shift in our way of thinking. We stand now at one of those rare moments in history in which philosophers may actually contribute something useful. However, 500 years or so from now, when all of this is completely worked out and part of established science, the textbooks about it will not contain a lot of the philosophical jargon and abstraction now present in the consciousness literature. You will not, for example, read terms like "modality", "token identity", etc.
Nevertheless, you will be disappointed if you expect these essays to nail down some schematic model of consciousness, with boxes and arrows showing how it is all put together. While we can (and perhaps must) make tentative stabs at building good metaphors, such models, interpreted too literally, are premature. We need to figure out some metaphysics first, to characterize the sorts of bricks we have to work with before we can speculate about what we might be able to build with them. We are still waiting for our Newton, let alone our Einstein. We are still in the brainstorming stage, and these essays should be read in that light. Any serious discussion of consciousness which pretends to more formality or precision than the current state of understanding warrants is, to some extent, disingenuous. I like to compare current philosophy of mind to Aristotelian physics - anything goes, and people basically get to make stuff up out of whole cloth.
While I don't have much use for true fruit loops, I think someone has to get a little loopy in consciousness studies. We have nothing to gain by being conservative. A lot of people seem to acknowledge that consciousness poses a problem for orthodox materialist/functionalist accounts of the mind (more on these terms later), but no one gets much beyond that. The Ice Age of Behaviorism has thawed, and people are now often heard using the C-word in polite conversation, but are generally still too afraid of losing respectability, or seeming unscientific. We are going to have to get a whole lot bolder than that if we are to make any headway, I'm afraid. We aren't going to scale the wall before us unless we allow ourselves to get a little - dare I say it - Continental.
One thing that has struck me the more I have thought about it, and that will be a theme throughout these essays, is the ambiguity surrounding the word "physics" and the mischief that results from that ambiguity. In particular, we anthropomorphize physics all the time, projecting ourselves onto it. I will try to deflate this projection, and introduce a little discipline into our thoughts about physics, emphasizing just how little physical causation buys us. Physics is blind. The billiard balls knocking together (classical or quantum) are "windowless monads", to use the philosophical term. They don't scale, at least not in any way they "know" about, any more than a pile of sand does. We may choose to regard aggregates or clumpings of stuff or their dynamics as "higher-level" things, but this is more projection on our part (may-be-seen-as sorts of things), and has no explanatory power as far as the universe is concerned as it crunches along, doing its micro quantum foam thing, moment to moment. Any systemic properties, while consistent with the mirco-causation, are strictly in our own minds.
With the stranglehold of behaviorism broken at last, there is a surge of interest in consciousness, and a growing acknowledgment that there is a deep, deep problem here. It is exciting to bear witness to a critical mass of smart people coalescing around a problem like this. There is big science here that only some people are just beginning to speculate about. Future history will remember this as the time just before the revolution. It is a great thing to be here now. In general, I am impressed with the integrity of the inquiry so far. Almost without exception, the contemporary books and articles about consciousness I have read are written by honest people just trying to get to the heart of the problem. They use plain language, and are willing to admit what they don't know. This bodes well, I think.
People have tried to figure out consciousness for millennia. Why should we crack this nut now? Basically, we have better tools now. Maybe not good enough tools, but certainly better. Obviously neuroscience and physics have progressed since Descartes' day, but we also have some versatile conceptual tools. Along with the 20th century's explosion of information technology, there has been a great deal of rigorous thinking about computation and symbol manipulation. The closely related field of information theory has also helped us invent a language which allows us to begin to talk about ways in which the brain might work. A century or so ago, the operative conceptual model of mechanistic functioning was the steam engine. Now the operative conceptual model is the computer, which, while insidiously misleading in some ways (I think), is a step closer to the truth. At least it is more illuminating to think about why minds are not like computers than it is to think about why they are not like steam engines. So maybe we will make it over the hump this time, or maybe we will fall back, fall apart, and the problem will lie dormant for another 50 years. I can't tell. I just hope we break through in my lifetime.
If we were to conduct a little office pool, I'd give it several decades. Let's say, by October 30, 2038. The state of the field of consciousness studies is somewhat analogous to the state of physics in the year 1900. Most physicists at the turn of the 20th century thought that they pretty much had the basic conceptual apparatus, and just needed to flesh out the details (Max Planck's physics teacher famously advised him to take up the piano, as there was nothing left to do in physics but fill out a few more decimal places). But by 1900, there were some experimental results which could not be explained within the current theories (the so-called black body radiation experiments). Some people were beginning to suspect that they were missing a big piece of the picture. This is essentially where we stand with consciousness. The year in which we finally had a complete, unified quantum theory is usually given as 1927, so I figure a few more decades of flailing, plus a margin of about 50% because we don't even have the same sort of firm Newtonian style framework for consciousness that physicists did in 1900.