I have tried, in part 1 of this book, to do what no one has done before: to explain how phenomenal consciousness could be an evolved feature of the human mind. My particular suggestions about the brain basis may be wrong. But in putting them on the table, I hope I have persuaded you that a naturalistic explanation of consciousness is at least a possibility in principle.
My theory is not quite the “transparent theory” that has been called for, “one that, once you get it, you see that anything built like this will have this particular conscious experience.” But it is getting there. I would say we have every reason to believe that if a human being were to have evolved to be built like this, he would end up thinking, saying, and doing all of the right things for us to suppose him conscious—and of course for him to suppose it too. What is more, a human being could have evolved to be built like this, because there would have been a natural trajectory through the biological design space, leading him from primitive ancestors to where he is today.
So now let us put the question of what behind us. Now the challenge is to explain the purpose of it all. We can be sure it did not happen accidentally. It must be the result of natural selection favoring genes that underwrite the specialized neural circuits—whatever they actually are—that sustain the illusion of qualia, giving rise to the magical mystery show for the first person. And it is axiomatic that this will have happened only if those lucky enough to be spectators of this show have somehow been at an advantage in terms of biological survival compared with their less fortunate cousins.
In chapter 1 I mentioned the idea of a philosophical zombie—the philosophers’ fantasy of a creature who is physically identical to a normal human being but completely lacks conscious experience. “Philosophical zombies look and behave like the conscious beings that we know and love, but ‘all is dark inside.’”1 I gave reasons for saying that, in principle, philosophical zombies do not and could not exist. However, it has to be part of my evolutionary argument that these zombies have a near relation that could certainly exist. We might call it a “psychological zombie.” A psychological zombie, let’s assume, is physically identical to a normal human being except in one crucial respect: namely, that he or she lacks just those evolved circuits in the brain that yield the phenomenal quality of conscious experience.
Would psychological zombies look and behave like the conscious beings that we know and love, despite the fact that all is dark inside? No, that is exactly the point. If consciousness is an evolutionary adaptation, the answer has to be that they would not. There must be things that a psychological zombie would do differently precisely because all is dark inside. And for natural selection to have seen this, this difference must result in the zombie’s being less likely to survive and reproduce. Compared with a conscious human being, a psychological zombie would fail to thrive.
In the pages that follow, I will discuss, in point after point, the possible advantages that conscious creatures might have over psychological zombies. But “psychological zombie” is a cumbersome term, so I will sometimes talk simply of “zombies.” Since I will be referring to creatures that are biologically credible (indeed, creatures whose like must once have existed on Earth and were outcompeted by the conscious creatures who came later in the course of evolution), I trust no one will confuse my zombies with the logically impossible and ultimately much less interesting philosophical version.2
But if conscious creatures did outcompete the zombies, why? What reasons are there to believe that the phenomenal richness of consciousness could play an essential part in anything of practical value? Here is a reminder of Flanagan’s definition of “consciousness inessentialism”: it is “the view that for any intelligent activity I, performed in any cognitive domain d, even if we do I with conscious accompaniments, I can in principle be done without these conscious accompaniments.” As Fodor has colorfully put it: “[Consciousness] 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? Nobody has an answer to this question for any mental process whatsoever. As far as anybody knows, anything that our conscious minds can do they could do just as well if they weren’t conscious. Why then did God bother to make consciousness?”3
Fodor is undoubtedly asking the right question: “why . . . did God [or natural selection] bother to make consciousness?” But I believe I know why he finds it all so baffling (“I understand his ignorance,” as the poet Coleridge would say).4 It is because he is looking at the problem from entirely the wrong angle. Note the bias in both Flanagan’s and Fodor’s formulations, toward thinking of consciousness as contributing to the capacity to do something. They are both assuming, as indeed almost everybody does, that the role of phenomenal consciousness—if it has one—must be to provide the subject with some kind of new mental skill. In other words, it must be helping him perform some task that he can perform only by virtue of being conscious—as, say, a bird can fly only because it has wings, or you can understand this sentence only because you know English.5
However, I have another idea. What if the role of phenomenal consciousness is not this at all? What if its role is not to enable you to do something you could not do otherwise but rather to encourage you to do something you would not do otherwise: to make you take an interest in things that otherwise would not interest you, to mind about things you otherwise would not mind about, or to set yourself goals you otherwise would not set?
I hedged my bets in the introductory chapter and suggested that consciousness has its effects on survival by changing what we may loosely call the subject’s psychology—knowing that the term “psychology” could cover just about everything the mind is involved in, from cognition to self-expression. But from here on I want to put aside all the usual subject matter of cognitive science—intelligence, information processing, decision making, attention, and so on—where people have looked in vain for a role for consciousness, and to explore instead the impact of phenomenal experience on subjective purposes, attitudes, and values.
In short, I want to suggest that what having phenomenal experiences does is profoundly to change your worldview so as to change the direction of your life. It brings about a kind of Kuhnian paradigm shift in your take on what it’s all about.
Thomas Kuhn, of course, was concerned with scientific revolutions: “Led by a new paradigm, scientists adopt new instruments and look in new places. Even more important, during revolutions scientists see new and different things when looking with familiar instruments in places they have looked before.”6 But what, now, if led by the consciousness paradigm, human ancestors had adopted new instruments and looked in new places? Even more important, what if they had seen new and different things when looking with familiar instruments in places their unconscious predecessors had looked before?
A “consciousness paradigm”? We will have to explore what this could mean in practice. What difference does being phenomenally conscious make to the way individuals think about and conduct themselves? What beliefs and attitudes flow from it? In the case of humans, if not other animals, what transformations does it bring about in the collective culture, and how do these in turn bring further changes?
These are—or ought to be—empirical questions: questions we can answer only by careful fieldwork in the realm of conscious creatures. So we need to engage in a thoroughgoing study of the natural history of consciousness. And it must be a program of research in which we are ready to consider all sorts of possibilities—not just those we would expect to find discussed in the science or philosophy sections of the library but perhaps those that belong in the self-help, mind and spirit, or even New Age section.
What we have to do is what Daniel Dennett has called “heterophenomenology” (phenomenology from another’s viewpoint). Here is Dennett discussing how Martian scientists might set about their consciousness fieldwork (Dennett flies in his investigators from a nearer place than I do): “Among the phenomena that would be readily observable by these Martians would be all our public representations of consciousness: cartoon ‘thought balloons’ . . . soliloquies in plays, voice-overs in films, use of the omniscient author point of view in novels, and so forth. . . . They would also have available to them the less entertaining representations of consciousness found in all the books by philosophers, psychologists, neuroscientists, phenomenologists, and other sober investigators of the phenomena.”7
However, I would go further than Dennett. I think this list is still too cautious and biased toward traditional kinds of evidence. Neither he nor any other mainstream philosopher of consciousness seems to have recognized how consciousness may contribute to personal growth.
It is our good fortune, however, that other types of researchers have recognized this all along. We might call them the “alternative natural historians of consciousness”: on one side are painters, poets, musicians; on the other, followers of meditative religious traditions, such as Buddhists. Do not be surprised, therefore, if I call artists and monks to the witness box or if I make much of direct quotations from individuals rhapsodizing about their personal experiences. The things people say—and especially the things that are remembered and quoted as seeming right and interesting to other conscious beings—provide some of the best evidence we can get about what consciousness does.
In what direction will this testimony lead? I will not hold back my main conclusion, although I expect I may shock you with how simple it is (after a lifetime of working on the question, I have shocked myself).
I think that what the natural history reveals is that consciousness—on several levels—makes life more worth living. Conscious creatures enjoy being phenomenally conscious. They enjoy the world in which they are phenomenally conscious. And they enjoy their selves for being phenomenally conscious. But “enjoy” is too weak a term. In the case of human beings, at any rate, it would be truer to say: they revel in being phenomenally conscious. They love the world in which they are phenomenally conscious. They esteem their selves for being phenomenally conscious.
Moreover, as I will show in the coming chapters, for conscious creatures there is real biological value in all this. The added joie de vivre, the new enchantment with the world they live in, and the novel sense of their own metaphysical importance has, in the course of evolutionary history, dramatically increased the investment individuals make in their own survival.
I say “in the case of human beings, at any rate.” Should I say nonhuman animals too? And if so, which? The question of which other species are conscious, and which are sentient but unconscious—psychological zombies, in effect—is an issue we have not fully faced yet.
In presenting the evolutionary story, I have of course gone along with the standard assumption that human beings are not the first and only animals to have developed phenomenal consciousness. However, the grounds for this assumption are by no means as strong as we might wish. If there has been rather little systematic study of the natural history of consciousness in our own species, there has been still less for other animals. Indeed, if you look at Dennett’s list of the evidential sources that an alien scientist (but it could equally be an Earth scientist) might use to research consciousness in humans, you will realize that not one of these sources would be available for nonhuman animals, not even a chimpanzee, let alone a mouse. Chimps simply do not go in for dramatic soliloquies and so on.
You may think it would be absurd to suggest that human beings alone have consciousness. I would agree. Evolutionary considerations rule out the possibility that the whole thing began with human beings. However, this does not mean that consciousness just as we humans know it is widely shared with animals.
I drew attention in the previous chapter to how sensations amaze us humans in a variety of ways. But there is certainly no reason to believe that these varieties came all at once in evolution. It is surely more probable that consciousness evolved in stages and that today there still exist animals with differing kinds and degrees of sensory qualia.
For a start, given what I have suggested about the brain basis of the ipsundrum, it would seem likely that phenomenal properties were established independently in the different sensory modalities. So, perhaps, for our distant ancestors it was “like something” to experience touch before it was “like something” to experience sound or light. And it could still be the case today that some animals have consciousness in only one modality.
But beyond this, it would seem likely that different kinds of phenomenal effects kicked in at different times: temporal thickening, the absolute separation of quality spaces, aesthetic valency, intrinsicality, privacy, ineffability . . . In an order we cannot yet specify (although ineffability could hardly have been an issue for prelinguistic creatures). Again, this would imply that some animals today are more richly conscious than others.
True, we might want to argue that the single most important transition was the first one: from being like nothing to being like something—and that all the rest is icing on the cake. Maybe in some sense that is right. You are either in flatland or in three dimensions; you either enter a magical nonphysical world or you do not. Arguably, the truly revolutionary development must have been when, perhaps quite soon after sentition became privatized, some chance change in its configuration first created the subjective illusion of being in the presence of something magically different. But if this was indeed the tipping point, it was still only the prelude. There would still have been a way to go before the full-blown magic show of consciousness was on the road, plenty of scope for “improving” sensations so as to make them ever more impressive.
Lacking the evidence to clinch it (though with plenty of suggestive evidence to be considered in the coming chapters), I may tell you my guess is that the self-made show did not become outrightly soul-hammering, in the grand sense Kandinsky was alluding to, until quite recent times—and maybe only thanks to advances that occurred specifically in the human line. Though I am jumping ahead, I will say it now: no nonhuman animals make of consciousness what human beings do. Consciousness may indeed contribute to a sense of self in nonhuman animals. But there is no evidence that any nonhuman animals, whatever the level of their consciousness, have gone on to invent the idea of a “person,” an “I,” let alone a “soul” with a life beyond the body (which is, of course, precisely why Dennett’s list of the “evidences of consciousness” cannot be used with animals: they are all essentially “I” related).
How far this specifically human notion of selfhood has followed on from innovations in what sensations are like for humans—that is, primary facts about the quality of human consciousness—and how far on feedback from culture, once humanity as a cultural phenomenon came of age, are issues we have still to explore. I am sure most theorists would put their money on cultural influences. Yet the fact is that humans have evolved rapidly since they split from chimpanzees five million years ago. Their brains and minds have undergone radical rewiring. And, remarkably enough, new research in comparative anatomy shows that human brains have diverged not only in higher executive functions but also in the early stages of sensory processing. The primary visual cortex in humans has an extra layer of cells that does not exist in apes or monkeys. Todd Preuss and Ghislaine Coleman, who made the discovery, comment: “The existence of substantial differences in the organization of primary visual cortex between human and nonhuman primates (including the commonly studied macaque monkeys) may come as a surprise, given how widely held is the conviction that the human visual system is basically or essentially similar to our close relatives.” There is no evidence yet as to what this extra layer is doing. The authors suggest a “low level” explanation in terms of differences in visual attention and perception of movement. But I wonder if they are not underestimating the significance of their discovery. Might not this extra layer be just what is needed to create a uniquely human kind of reverberatory loop? At least let’s not rule out the possibility that the wonderfully inflated human self-image has arisen out of some more basic change in sensory phenomenology—one that has happened in the human line alone.8
Let’s revisit this question of grades of consciousness when we know more about what exactly is at issue.