The recent scientific approaches to consciousness emphasize different aspects of conscious experience and different brain and mind states that are correlated with those experiences. We might divide them into "inside" approaches and "outside" approaches. For a philosopher, the quintessential conscious experience is to sit in the proverbial armchair and look inside your own mind. Since Descartes, some philosophers have argued, on the basis of this sort of reflection, that to be conscious is to have a sense of oneself. If I am conscious of the blue of the sky, I must know not only that there is a blue sky but that there is an "I" looking at it. This is the type of consciousness you experienced when you tried to decide whether you were conscious of your feet in your shoes. It involves that mysterious inner "I" who is also your inner eye, your autobiographer, and your chief executive officer. Other "inside" approaches emphasize focused attention and intentional planning. Psychologists like Stanislas Dehaene and Bernard Baars describe consciousness as a "workspace," a kind of phenomenological desktop on which that mysterious "I" places, arranges, and manipulates information. We've learned a lot about this inside type of consciousness. We know, for example, that the workspace has a limited capacity; we can crowd only so many things on that desktop. And we even know some of the brain networks, involving parts of the frontal cortex, that support attention, planning, reflection, and our sense of the self.
For Damasio as well, some sense of self is essential for consciousness. His contribution has been to suggest, plausibly enough, that our experience of the abstract Cartesian self has its roots in our perception, literally, of the inside of our bodies. In some not very clear way, the more primitive sense of self that comes with having a body is elaborated into the reflective self of philosophical consciousness. Perceiving my mind in the armchair depends on perceiving my behind in the armchair. And, in some other not very clear way, this allows us to evolve from being a mere bodily organism to a creature with awareness.
"Outside" accounts of consciousness, on the other hand, tend to come from scientists, like Christof Koch, who study visual perception and who (no surprise again) think that perception is the key to consciousness. For a vision scientist, the quintessential conscious experience is to look out the window and simply see the blue of the sky, irrespective of the body, the self, attention, planning, reflection, and all the rest. The philosopher Ned Block calls this type of consciousness "phenomenal consciousness," in contrast to the "inside" "access consciousness" of introspection. It includes all of our perceptions and experience, everything that we feel at all, the blue of the sky, the coo of the birds, the fuzzy stuff at the periphery of our vision. It even includes the very annihilation of self we experience in the moments before sleep or in some dreams, or when we're blissfully absorbed in a book. It's the feeling of my feet in my shoes before I turn around to think about them. Phenomenal consciousness is more pervasive than access consciousness, but it is also more elusive. We've learned a great deal about how these types of conscious experience are related to the brain and mind—about exactly why the sky looks different in different lights or why the world looks colorful by day but black and white by night.
Damasio suggests that phenomenal awareness depends on the sense of a self. But, actually, there is evidence that the two types of consciousness may even be in tension with one another. For example, Rafael Malach and colleagues have studied what happens when people watch an absorbing Clint Eastwood movie in a brain scanner. In those circumstances, the frontal "self" network actually shuts down while the more purely visual parts of the brain are activated. This mirrors our experience. When we watch an absorbing movie we lose the sense of our selves, but we are vividly and profoundly conscious of the movie itself. In fact, shutting off planning and attention, by sitting still and inhibiting our sense of self, can lead to enhanced awareness of the world outside, as in some types of meditation. Babies and young children, who have a much more attenuated sense of self than we do, may actually experience the world outside them more vividly. For them, consciousness may be a kind of lantern illuminating everything around them, rather than the narrow-beamed flashlight that the grown-up philosophical self, like an X-files detective, keeps waving about to fitfully illuminate the psychological darkness within.
Which kind of consciousness is primordial? Is the self fundamental for consciousness, as Damasio suggests? Or does awareness come when we take in information without having to do anything about it, and is the attending and planning self merely an elaborate construction on top of that, as the Buddhists or David Hume would argue?
I suspect that the answer will turn out to be that the dichotomy between inside and outside is itself too simple. It may be that, as in the case of "life" in biology, self-reflection, attention, dreaming, planning, vision, bodily perception, emotion, and all the rest are simply too varied to have a single explanation. Helping to solve the separate pieces of the puzzle, as Damasio did in his earlier work, may always be more satisfying than speculating about a single grand design.