I. Theories without Experiments
Imagine, dear readers, physics without experiments or measurements. Actually, you don't have to use your imagination because it already happened. It looked, at best, like Aristotle: “heavier things fall faster,” “the earth is at the center of the universe and planets move around it in regular circles;” and in the great majority of cases it was just a collection of flat-earth folk superstitions indistinguishable from mythology.
In fact, the ancient Greeks already had access to experimental data in the form of Babylonian astrological measurements, but for the purpose of the little story that follows we'll pretend those were all destroyed by Murshili I in the sack of Babylon and at any rate not accessible from the steamy setting to which I hereby invite you.
"Bathers, Bathers, Ockham's Razors"
The Persians aren't attacking today and you're bored. So you and your friends and Aristotle decide to hop over to the bathhouse and make a game of proposing alternative explanations for the motions of celestial bodies.
One of your friends tells Aristotle that the wandering stars don't circle the earth in exact circles but instead wobble on epicycles. He draws them in the steam on a marble bench: circles on circles. Very creative, you say, and indeed here in this bathhouse we can't make measurements to prove you wrong, but all the same rather unlikely; and your friends agree that plain circles are a much more convincing account of celestial motions, for the epicycles feel quite artificial.
Another bather proposes that the wandering stars move in ellipses. This seems more plausible than wobbling circles, and there's a lot of praise for his solution; but a friend of Aristotle's, whom we'll call Hippomedes, points out that circles are more consistent with the likely explanation that celestial bodies are stuck on transparent spheres surrounding the earth, whereas the criss-crossing of so many ellipses would rule out the existence of these spheres, and then how would the stars stay in the air? Ockham's Razor hasn't been invented yet, but after weighing the theories in their minds everyone agrees that this ellipse hypothesis, while more appealing than epicycles, is still overall too complicated and less convincing than circles alone.
A young boy of twelve or so of whom Hippomedes is particularly fond proposes that the circles might not be centered exactly on the earth and that perhaps the earth is even moving, and everyone laughs at what a sweet boy he is; and then Thrasymachus interrupts with a more sophisticated theory, namely that falling objects on earth and circling objects in the sky move according to the very same laws of motion. You congratulate him on inventing such a fascinating idea, but when you prod him for a further explanation he's unable to say why this would be so, and no one else can put the pieces together either. Thus the circle theory still stands.
Now Athena decides to play a little game with our group of bathers. She appears beside Xenophanes (well, not literally appears: she's invisible) and whispers into his ear that time passes at a different rate for observers moving at very fast speeds; and Xenophanes speaks these words as if they were his own. The bathers' minds are boggled by a theory that everyone agrees is very original, but one of the assembled rode the fastest horse in Athens all the way to Thebes without perceiving any temporal peculiarities; and while in his opinion it's a good basis for a science-fiction story involving Theseus, a minotaur, and a ten-light-year-long spider thread, it seems to have no basis in reality.
Aphrodite is jealous of the way Athena has been cozying up to these bathers, so she appears in the steam beside you. She rests her hand on your right shoulder and says sweetly to your left ear that everything consists of miniscule particles whose properties are undetermined until you observe them—which you can't, because, remember, this is physics without experiments. But you're too busy peeking inside Aphrodite's toga to give her words more than cursory attention; and besides, it's surely the most implausible of all the theories proposed today, so much so that you'd feel embarrassed to share it.
You all return from the bathhouse having had a good bit of fun, and more confident than ever that the circle theory of celestial motion, being the simplest and most plausible, is the correct one—and also that heavier objects fall faster than lighter ones.
II. Proposed Solutions to the Mind-Body Problem
Is this an essay about the mind-body problem, or is it a brief history of physics written by a mere artist who has no business writing such a thing?
I'll stop being coy. My point here is that because philosophical theories about consciousness (or mind: I'll use the words interchangeably here) are for the most part not experimentally testable, we don't have sufficient evidence at hand to distinguish the true theories from the false, and the tempting ground for doing so—a feeling of plausibility and psychological satisfaction—just doesn't work. Our Greek bathhouse story showed that in the absence of evidence the least plausible theories may turn out to be the correct ones. I wanted to make this point at length because, although people admit it's correct if you corner them and ask them forcefully, they'll forget and start arguing from plausibility again as soon as you let them out of their corner; and I'd at the very least like them to remember this story well enough to feel a little shame when they do it.
So, how does the conscious mind relate to the body and the physical world of matter? Let's take a tour of some theories, just as we did for physics.
The predominant theory amongst intelligent people today is that consciousness is an emergent property of matter. That is, from a certain configuration of matter, consciousness . . . emerges.
Hm. This theory is a pet peeve of mine. I think, basically, that it sucks. “Emergent” is just a magic word to cover over something no one understands, by analogy with e.g. a tornado, where a macro-level phenomenon is produced by a concatenation of micro-level phenomena; the critical difference being that tornadoes and moving particles of air are fundamentally the same sort of thing, whereas consciousness and matter are absolutely different categories of things—more different than the taste of chocolate is from the song of a cicada, whose rapidity does not cause a taste to emerge from a sound. The analogy, and the word, are almost dishonest; or at least the dictionary should add a definition to the word emergent:
3. Adj. Something whose workings I don't actually understand but, by virtue of this magic word, now feel like I do. See also: Om.
Almost, though, is a word into which much can be squeezed. The emergence theory might not actually explain anything, but just because it creates the illusion of knowledge doesn't mean it's false in every respect.
In fact, all credible mind-body theories acknowledge that consciousness, to the extent we can identify it in this world, is correlated with special material states, and that when you destroy these material states you thereby diminish the contents of consciousness. Apart from these trivialities the only substantive claims of emergentism are that matter is the primary level of reality, and that when you completely destroy the special arrangements of matter that generate consciousness, you completely destroy consciousness too.
Are these claims true? Well, when you get right down to it we can't observe the result of the ultimate experiment here on earth. If you wake up in the next life after your brain explodes in this life, then you'll know emergentism is false; otherwise, you can't be sure either way. Nor can we do an experiment that would show matter persists without observers, because—we couldn't observe the result!
So, the only non-trivial claims of emergentism can't be experimentally proven any more than our ancient Greek bathers could have proven relativity without leaving their bathhouse.
Another theory, currently popular among academic philosophers, claims that qualia are “properties” of the smallest physical particles (qualia are colors, smells, tastes, and other conscious experiences of this sort). We can't observe these properties from the outside, but we can experience them from the inside, because our brains are composed of such particles.
The issue with this theory is known as the “combination problem”: how could many simple qualia in tiny particles form the very complex qualia we're conscious of? If you combine yellow and red particles do you get orange? What combination of yellow and red particles, then, gives you the smell of cinnamon? It's difficult to conceive how such combination would work, and it would seem that one needs either an extraordinarily high variety of qualia in the particles—none of which are physically observable when we test them in a laboratory—or else some way to turn unlike things into like things, e.g. turning three yellows and a red into cinnamon.
So, there's an explanatory gap in this theory too. It's not as big as the gap in the emergence theory, but it's nevertheless such a big gap that not only are we unable to do any experiments that would close it, we can't even convincingly explain in theory how it could be closed. Does that mean we've proven it wrong? No. There's no logical contradiction in the theory. Maybe it's true and we just can't figure it out for lack of information, the same way our bathing Greeks couldn't figure out quarks.
A third theory turns this composite-consciousness concept upside-down. Instead of being composed of particles, this theory holds that individual minds are divided off from some kind of vast cosmic consciousness.
Yes, you're inclined to be dismissive of a theory that's obviously derived from Adi Shankara, but it has considerable support in mleccha universities today, and since its academic proponents know it already sounds a bit silly and don't want to be taken for hippies dabbling in Hindu theology, they never cite him. (Some hold too that the whole universe of matter is the external view of God's mind in the same way that the brain is the external view of human minds; a theory that seems to derive from Ramanuja, whom they also do not cite—I mean, I never cite anyone either, but I'm not pretending to be part of a respectable intellectual community: I mainly write about odalisques).
The appeal of cosmopsychism, as it's called, is that it escapes the combination problem. The smell of cinnamon already exists in the cosmic stream of qualia; it doesn't have to be put together from yellow and red particles. Instead the difficulty lies in articulating just how this vast stream is filtered down to our more limited consciousness, how minds are separated from each other, and what the brain, which doesn't really seem to behave like a filter, has to do with it all. I've heard people claim there are satisfactory answers to these questions, but I have not been fully satisfied myself. Of course, once again, this explanatory gap doesn't mean the theory is false.
Perhaps the most thoroughly denounced mind-body theory is that the soul, which is the seat of the personality and decision-making, exists outside the body and merely interfaces with the body through some organ; purportedly the pineal gland, but we'll just say the brain. This theory seems implausible because we know empirically that brain trauma can change character and decision-making, and therefore these must be tied to the physical brain in some fashion.
But allow me to play angel's advocate. Perhaps the brain is just like RAM on which consciousness in this world needs to run, whereas the soul, which exists elsewhere, contains a hard drive that stores all the data and a processor that makes certain decisions; so that even if the RAM is destroyed, the hard drive and processor persist, but the machine in this world stops working properly.
“Implausible,” you say. Less implausible than quantum physics, surely; and remember, we are not accepting argument from plausibility.
“You can't reason that way: you're assuming things are happening in some realm that we can't observe and of which there's no evidence here on earth,” you retort. Oh? If you knock me out and toss me into a cell with no windows, I'm not allowed to imagine what's going on outside the cell that I will see when I leave it? How is this a rule? It's not a rule, it's nonsense. I'm not endorsing Descartes' theory, but I don't see that we can completely exclude it from contention either. Except for the part about the pineal gland: that's out.
A lovely theory with few adherents today is that we each live in our own isolated bubble of consciousness, which actually never touches nor interacts with other bubbles of consciousness. We only have the illusion that they interact. Matter doesn't even exist, it just looks like it does. The reason we all see the same things despite never interacting is that God arranges it thus. Or, if you don't like God, you can say that some natural law does exactly the same thing. (“Because it's a natural law” doesn't have any more explanatory power than “because God wanted it that way,” but for some reason people seem to believe otherwise.) This pre-established harmony of perceptions in non-interacting bubbles is widely dismissed, but I don't see anything logically wrong with it, nor do I see how it contradicts the limited empirical information we have. While equally untestable, it makes fewer assumptions than the preceding theories, and for that reason one might consider it more beautiful. Beauty doesn't prove truth any more than plausibility does, of course; but there's still no reason to conclude this theory is false.
I'll end our whirlwind tour of the mind-body problem with a touch of comic relief.
A common mistake made by people with little time to explore philosophy is to assume that materialism is the only standpoint compatible with empirical science. This isn't true at all. Materialism, moreover, is a metaphysical theory, it is not an anti-metaphysical theory or a non-theory, although those who hold it often believe they are thereby refusing to engage in metaphysics.
Now, some materialist philosophers today believe the very existence of consciousness is a threat to materialism. But they are so invested in materialism that they can't risk losing it. These ultra-materialists have the fanatical devotion of the Spanish Inquisition, a suicide bomber, or a self-immolating monk. So they go all in, they take the plunge, they crash the plane into the building: they deny that consciousness even exists! No, really.
Just shoot them, they won't notice.
Moving on . . .
III. Belief at the Limits of Knowledge
So many interesting theories, eh? And what I'm here to tell you, dear readers, which the proponents of these interesting theories never bother to tell you, is that we simply don't have the grounds to decide which one is true. Even if some of them are a bit implausible, we know, from the history of physics examples that opened this essay for a reason, that we can't replace argument from evidence with argument from plausibility. The least plausible theory prima facie may be the true one.
So, what do we actually know and what do we not know?
We know that the contents of consciousness are correlated with matter as it's understood by physics and chemistry and biology, but not reducible to matter, partly because consciousness has qualia and matter does not. We also know that consciousness has to be the ground of knowledge, including knowledge about matter.
And that's about all we know.
There's no reason, for instance, that we would need to believe the claim that our qualitative perceptions aren't primary reality. That's just one theory among many, and hardly the best theory.
The openly religious believe on faith that matter isn't the ultimate reality and that consciousness persists after death; and whether it does or doesn't—we don't know and can't prove it—there is indeed room for them to hold this belief without contradicting reason, evidence, and science. Materialists will often assert with utter confidence that minds are destroyed when matter is destroyed, but the fact remains that they too don't know this and can't prove it, and all the confidence in the world won't change that—they want to be the guy who informs the world that Santa Claus isn't real, but what they are is faithful who won't acknowledge themselves as such: they've never even been to the North Pole! (The cold, rationalist, skeptical standpoint on the mind-body problem is agnosticism, not strict materialism.)
Proposing solutions to the mind-body problem is a lot of fun, much like the fun that our Greek bathers had doing theoretical physics without any experimental data. I'm not going to tell anyone to stop coming up with new theories or stop arguing their merits. But since our ability to experiment is extremely limited and we can't reach the truth by arguing from plausibility, the area of possible solutions—basically anything consistent with logic and the minimal empirical evidence we do have—is simply too large to isolate a definitive answer.
That's why, dear readers, I fall back on the pragmatical principle I enunciated in my essay on religion:
Faced with an unknowable, one should adopt the most beneficial theory as a working hypothesis.
The pragmatical principle might not give you the truth, but it does give you the good—which is, almost by definition, better than the truth. If you don't feel like following the pragmatical principle, agnosticism about the mind-body problem beats some popular alternatives.
So what's the most beneficial theory? Well, that's for you to decide, but in my view it's a form of idealism. The alternatives tend to entail some degree of reductionism that makes the most meaningful aspects of our conscious experience less meaningful than they could be; in the worst cases we're encouraged to think of them as merely epiphenomena of the behavior of chemicals and nerves. (If you're interested in reading a rigorous critique of scientific reductionism I recommend Husserl's Crisis.) This isn't a very rewarding way to think, though materialists will braggingly tell you how much they enjoy believing that love is really just hormone X, Y, and Z plus a dash of DMT. Clear-minded idealists will easily admit that love is correlated with these material things, but without assigning them the ground level of reality, let alone dismissing the rest as epiphenomenal.
Matter doesn't exist independently of consciousness. Rather, it's a reification of regularities within and between consciousnesses. The laws discovered by science are descriptions of these regularities and retain their full validity.
With this stripped-down and extremely simple theory one avoids reductionism, the combination problem, and the difficulty of explaining causal interaction between matter and mind that arises if these are understood as fundamentally different modes of being.
Regarding the immortality of the soul, I will refer you to my essay on religion, and say here only that amongst the possible solutions to the mind-body problem there are many that permit the mind to persist in some form after the destruction of its material correlates.
So, to sum up my main points:
- The mind-body problem isn't solvable because there are too many logically possible solutions and no way to empirically verify which are correct.
- We can't assume plausibility or simplicity will allow us to choose the best of these possible solutions.
- There's no reason to default to materialism. We should either remain agnostic or adopt the most beneficial theory as our working hypothesis according to the pragmatical principle.