In any given season, almost any month, there seems to be a new book on consciousness. To take just a few recent titles, almost at random, there is Consciousness by Allan Hobson, The Mind’s Past by Michael Gazzaniga, and The Race for Consciousness by John Taylor. Any author might be daunted by the challenge of distinguishing himself in this ﬁeld. Not so A. G. (Alexander Graham) Cairns-Smith. He has done so handily. Secrets of the Mind is without doubt the jolliest, most breezily written volume now extant on neuroscience’s most profound question. It has no peer.
Don’t go away. This is a serious book from a canny scientiﬁc mind. Cairns-Smith, a Scottish chemist, now retired from the academy and writing well-received popular science, must have been a marvelous teacher and a cherished campus eccentric. How about this (after quoting a passage on neurotransmitters and voltage-sensitive gates for calcium):
Now that’s science, no question. But talk of Resentment, Jealousy, Lust...? Will the doorman of the Great Hall of Science let us in with such folksy notions? Perhaps we will be asked politely to leave such ideas in the cloakroom, along with flick-knives, cigarettes and other undesirables. (“Yes, sir, just leave them in the tray marked ‘subjective rubbish.’”)
With rhetoric like this, Cairns-Smith describes the structure of proteins, quantum theory, and the visual cortex—and manages to convey quite a bit of accurate information.
Unlike much popular science writing that guides the reader through a particular neighborhood, pointing out the new projects, Secrets of the Mind is a book with an argument. Cairns-Smith has his own version of The Astonishing Hypothesis, Francis Crick’s 1994 investigation of the nature of consciousness, and pushes it hard. In fact, an admirable feature of Secrets of the Mind is that it plainly reveals the bones of this argument, beginning with a complete preview, stopping along the way to lay out explicit premises, and concluding with a recapitulation. Cairns-Smith makes his points so bluntly, it sometimes seems, that it takes an effort not to dismiss him. (If we can mistake obscurity for profundity, can we also mistake clarity for superﬁciality?)
CONSCIOUSNESS, QUALIA, AND THE PHYSICAL WORLD
He begins with what philosophers call qualia. Since Secrets of the Mind is about qualia, it is important to get clear how Cairns-Smith uses the term. He writes: “I will say that the essential features of consciousness are sensations and feelings—a sensation of pain, or of the colour yellow, or a feeling of anger or enthusiasm... Philosophers call these things qualia.” Qualia, then, are our immediate mental experiences of the world: our experience of the redness of red, the painfulness of pain. As I understand Cairn-Smith’s position, these qualia—these feelings and sensations—are the touchstones of consciousness because they cannot be unconscious. (Thoughts, he maintains, can be unconscious and, although obviously they can be conscious as well, they then have “associated sensations and feelings.”)
He then advances the proposition that he devotes the balance of his book to making plausible. It is that qualia are—must be—physical. The challenge in making this idea plausible is that many people ﬁnd it impossible even to comprehend. What does it even mean to say that our feeling of pain or our experience of yellowness is physical? Not simply caused physically, but themselves physical?
Cairns-Smith is sympathetic: “[T]he idea is so unpalatable that I hardly dare whisper it here. It is that we belong, body and soul, to a physical world....”
The kernel of his case is that qualia (remember: the feeling itself, not its origin) must be physical because they evolved. This is not a new idea (William James had it), but Cairns-Smith believes that its implications have been largely ignored. It is, in fact, a “bomb in the basement of modern science” (a vintage Cairns-Smith conceit), for it implies—if fully understood—not only that consciousness itself is a purely physical phenomenon but also that the physical sciences, which seem to utterly exclude this possibility, must be cruising for a big upset.
This argument from evolution is worth examining more closely since Secrets of the Mind pivots on it. That qualia arise from the brain (not especially controversial), causally affect the brain (more controversial), and are themselves physical stuff (very controversial)—all are implications of qualia having evolved. Pain, after all, ﬁts very well into the survival scheme of animals. Here’s his nutshell:
Elaborating proposition 2, he writes: “Feelings such as hunger and lust have obvious parts to play in surviving and having offspring. They are well adapted for this, contrived for these purposes as are countless other such elements of consciousness.”
The argument to here, I gather, Cairns-Smith considers demonstrable. The bomb is real; qualia are physical. Our feelings arise in the brain, are efﬁcacious in causing behavior, and—in some way scarcely imagined—must themselves be “stuff.”
Of course, when he even asserts that qualia are real, separate features of the mind—never mind “physical”—Cairns-Smith is in disputed territory. For example, he is now at odds with what I take to be Daniel Dennett’s position that a complete, adequate understanding of the brain need not involve qualia; they are just a different way of referring to the neural machinery. Cairns-Smith is not buying this:
Why do so many people seem to imagine without discussion that qualia have to be identical to (some) “normal” neuron activity? Caused by such activity, yes, in part at least; correlating with it, certainly: but identical...? ...a much too hasty and mistaken identification of something we do not understand with something we pretty well do.
THE QUEST FOR THE “QUALAGEN”
Comfortable with his premises that qualia exist and must be physical, Cairns-Smith begins the real adventure: a shrewd search through the neural machinery, posing this question: What is there in the brain that at least plausibly might be the creator of qualia? (For this as yet unknown mechanism he coins the term “qualagen.”) Cairns-Smith is impressively good at this kind of speculation. He has a scientiﬁc cast of mind, not only in his skeptical independence of thought but also in his feel for the kind of answer one might be willing to take. He likes to re-create the initial implausibility of earlier theories that we now accept: every object with mass attracting every other object across space with calculable force (Newton) or the mass of an object producing a curvature in the space around it (Einstein).
Well, how about neurons? A good place to create qualia? No; the time frame seems wrong, and there is too much action:
We know from our subjective experience that conscious events come and go on time scales of seconds, not the millisecond time scale of neuron firing. Imagine you are a harassed “pyramidal” neuron (one of the big ones in the cortex with long distance connections) and you are trying to help to put together a nice quale. All the WHAM! WHAM! WHAM!... huge changes in local voltage are hitting you every few milliseconds....One might want to look for a quieter place. Near the main action no doubt, connected with it, but perhaps not right in the middle of it. The outer reaches of a dendrite might be quieter.
Next we consider glial cells. There are lots of them, and different classes of them. Recently there has been evidence that glial cells are more than valets to neurons; they do some signaling, too.
Then there’s the limbic region. Certainly associated with emotions. Or visual region V-4 for color sensations?
Or is this all on the wrong scale? Perhaps consciousness is not at the top of the brain hierarchy. It may be at the molecular level. Perhaps molecules within cells, when they coordinate their activity with similar molecules, begin to play in an orchestra that transcends cell boundaries....What about protein molecules?
Protein molecules are likely to have something to do with the qualia-making machinery we are trying to imagine. They are relatively directly made from information in the genes. And we find that in cells of all kinds proteins do most of the clever stuff. So let’s suppose that protein molecules are at least critical components of the qualagens.
Is this science? Well, it could be categorized as a search for hypotheses. That is what Francis Crick does in The Astonishing Hypothesis, the book that did so much to start the scramble to understand consciousness. Crick’s explicit goal, however, was to suggest some testable hypothesis about consciousness, and speciﬁc experiments, so that science could “get serious” about it. Cairns-Smith certainly proposes hypotheses, but it remains to be seen if they are testable hypotheses; he does not suggest any experiments.
“THE STUFF OF WHICH DREAMS ARE MADE”
Having reached the suggestion that “qualia might arise from—might be—the organized oscillations of molecules,” we move on to the ultimate challenge. If qualia are physical, as they must be to have evolved, what might they be made of? What might be the physical fabric of our experience of red?
What might be the stuff that is the feeling of pain?
Is he kidding? Well, consider the alternatives. If qualia exist are they nonphysical? But this takes us where few scientists want to go, into a nonphysical substance, a spirit—and thus into Cartesian dualism. Typically, the escape from this trap has been to reduce qualia to identity with the neural activity of the brain. My experience of pain is just the ﬁring of my neurons in however complicated, as yet unexplained, fashion.
But this reductionism, too, has its problems. My thrill of pleasure at hearing a Mozart concerto is nothing like any kind of movement of physical particles, not like any ﬁring of action potentials or release of neurotransmitter chemicals. The two are incommensurate. But then, it is by no means obvious that Cairns-Smith escapes reductionism. Although he ﬁrmly asserts that qualia exist, and are not identical with neural activity, he also asserts that qualia are physical—albeit as a result of physical laws of which we may at present have no inkling.
Cairns-Smith’s search for the stuff of qualia—“the stuff of which dreams are made”—is characteristically intriguing and provocative. In a chapter titled “The Fabrics of the World,” he begins his search with quantum theory. This, by the way, is not a new place to look for consciousness. In fact, turning to quantum theory has been criticized as seeking the answer to one bafﬂing phenomenon (consciousness) in another set of bafﬂing phenomena (quantum events). Cairns-Smith acknowledges this objection but, he says, if we argue that consciousness is matter, “we should surely be prepared to deploy the deepest theory of matter there is.”
With typical panache, he spreads before us the paradoxes of quantum theory, such as photons, or quanta of light that “ﬂicker into and out of existence pushing and pulling the atoms and molecules that produce them and absorb them. What we call empty space is a maelstrom of such ‘particles,’ a chaos from which the fabrics of the world are woven.” Here it comes:
I am among those who like to imagine our consciousness as being made of one of these fabrics, and to say that consciousness, like light, is “a subtle form of matter.” It is not made out of atoms and molecules but is derived from the same substratum—that the organized qualia of consciousness are to be identified with particular organizations of this maelstrom; so that it is somewhere here, this stuff of consciousness, this fabric that the brain makes and manipulates in making its phenomenal world.
For this conclusion, he spins a supporting web of speculation on the evolution of eukaryotic cells, the evolution of protein, the nature of models and electromagnetic theory, never failing to stop to explain the new subject before he sticks it into his argument. It is an impressive performance, as is his 20-page reference section, thoughtfully annotated, that takes us through the literature on consciousness and the brain.
Cairns-Smith’s suggestion about the orchestrated resonance of molecules in the brain is not novel, of course, and is duly referenced in his notes, as is his suggestion about quantum theory and consciousness. In that sense, Secrets of Mind remains a “popular science” book, a meditation on the professional literature in its area.
The book is serious fun, which may be one of science’s most productive activities. For a shiver of wonder, for example, how about this: If qualia are physical, constituted of unknown matter, and organized on unknown principles, how do we know that qualia are only in brains? Cairns-Smith will gamely follow that logic:
Perhaps there are flickers of sensation and feeling in all ordinary physical and chemical processes, who can say? It is not unreasonable. We do know of a class of physical objects, brains, that produces them hugely.
Could such random qualia, occurring in chance arrangements in protein molecules, have become coordinated at some point, and then built upon by natural selection?
I ﬁnd it pleasant to imagine this distinguished chemist, now retired but still vigorous, utterly unrestricted in his investigative itinerary, striding determinedly from one enchanting scientiﬁc scenic overlook to the next—on a scientist’s holiday. It is almost irresistible to trot along behind him.
From From Secrets of the Mind: A Tale of Discovery and Mistaken Identity, by A. G. Cairns-Smith. ©1999 Copernicus Books. Used with permission.
Protein molecules are likely to have something to do with the qualia making machinery we are trying to imagine. They are relatively directly made from information in the genes. And we find that in cells of all kinds proteins do most of the clever stuff. So let’s suppose that protein molecules are at least critical components of the qualagens.
As molecules go proteins are big. A protein molecule in a cell is likely to contain several thousand atoms connected together in a particular way which allows the protein to be a machine with some particular function.
But as machines go proteins are tiny almost beyond belief. The innards of a Swiss watch, which used to be the standard for fine scale engineering, needs a magnifying glass to examine them. Today we have still smaller man-made mechanisms, such as computer chips, needing a microscope to examine them. Now try to imagine machinery on a still smaller scale, say a hundred times as small, needing a microscope, now, just to see it. A hundred times smaller again you would need an electron microscope. And then another hundred times smaller still you would need the highest powered microscopes available. Now at last you would be beginning to arrive at the territory of protein engineering, the engineering on which all life on Earth depends—of what most of life can be said to consist. In any cell in your body there will be many thousands of different proteins doing thousands of different things, and usually many thousands of copies of each of these types.
Imagine now that you could open up just one of the million billion cells that make up your body and prize out some of these exquisite pieces of protein machinery to look at in detail. Perhaps the first protein molecule you come across performs one of the myriad of chemical transformations that a cell must bring about to keep going. Next you might find a neat little cluster of another type of protein as part of a membrane, which helps to form a pore in the membrane that will let through just one particular kind of ion, say potassium. Or perhaps it’s a more complex cluster of several proteins that you had got hold of from the membrane that together act as a selective pump, pushing just certain molecules across the membrane in one direction only and using a molecular fuel to do it. Other proteins give the cell a kind of skeleton which helps to keep cells in shape, and very odd shapes they are in the case of neurons with their sometimes dense trees of dendrites, their sometimes long wandering branching axons. It is hard work making and keeping a shape like that. One class of these skeletal proteins form “microtubule” helping, among other things, to buttress axons. These ones also act as railways lines transporting materials between the cell bodies of neurons and their axon terminals—and yet other proteins act as little engines to do the pushing.
In the old days people talked of “protoplasm” as the magic stuff in cells, the stuff of life. Then when the complexities of the machinery in “protoplasm” were discovered there was substituted another kind of incredulity.
How could machinery that is so tiny be so complex, and work so well? Well it is, and it does. We might ask how the “protoplasm” of “brain matter” can be so contrived that it makes feelings and sensations, and so reliably. Well it is and it does.
Even if you want to say that it is at higher levels of organization that qualia emerge, at the level of cells or circuits or more complex assemblages of such things, all such things are made of molecules. It would still be true that qualia come from molecules, suitably organized.
But I am asking you to suppose that elementary feelings and sensations might arise from molecules more directly, that qualia might arise from—might be—the organized oscillation of molecules. Perhaps a particular quale arises when a particular group of protein molecules over a sizeable region of the brain is somehow “set going,” oscillating in their particular complicated way, like swathes of musical instruments contributing to a large scale effect. There has been some considerable interest in such ideas in recent years. They appeal to me, although it all sounds pretty crazy even to me. But I have learned not to be put off too easily by that (remember Issac Newton and his crazy idea). So I ask you to say “let us suppose that qualia are made like this, might it help?”— and then we can get down to more mundane matters.