Reality, real reality, is the matter-in-process that science describes, Dennett argues. Dennett is famously, insanely consistent in his materialism. Nagel writes, “Bach’s or Picasso’s creative genius, and our conscious experience of hearing Bach’s Fourth Brandenburg Concerto or seeing Picasso’s Girl Before a Mirror, all arose by a sequence of physical events beginning with the chemical composition of the earth’s surface before the appearance of unicellular organisms.”
Much of that real reality is completely outside our consciousness or understanding. We don't know how our brains work - no one does; we don't know much about how anything works. Our bodies function without our conscious control, yet the physical and chemical processes churning along anyway. We understand very little about our own real reality, and the world around us continues in its processes without our aid.
What we do know as direct experience is not reality. It is an evolution-created illusion, a “manifest image,” the “world according to us.” This manifest image is, Dennett explains, “a user-illusion brilliantly designed by evolution to fit the needs of its users.” Nagel explains, “In spite of the word ‘illusion' he doesn’t wish simply to deny the reality of the things that compose the manifest image; the things we see and hear and interact with are ‘not mere fictions but different versions of what actually exists: real patterns.'”
Consciousness too is part of the manifest image, the illusion within which we survive in the world. In Nagel's summary, “Dennett holds that consciousness is not part of reality in the way the brain is. Rather, it is a particularly salient and convincing user-illusion, an illusion that is indispensable in our dealings with one another and in monitoring and managing ourselves, but an illusion nonetheless.”
This view of consciousness leads Dennett to “deny the authority of the first-person perspective with regard to consciousness and the mind generally. . . . our conception of conscious creatures with subjective inner lives—which are not describable merely in physical terms—is a useful fiction that allows us to predict how those creatures will behave and to interact with them.” Farewell to Descartes, with a vengeance.
Nagel doesn't believe it: “Dennett asks us to turn our backs on what is glaringly obvious—that in consciousness we are immediately aware of real subjective experiences of color, flavor, sound, touch, etc. that cannot be fully described in neural terms even though they have a neural cause (or perhaps have neural as well as experiential aspects). And he asks us to do this because the reality of such phenomena is incompatible with the scientific materialism that in his view sets the outer bounds of reality. He is, in Aristotle’s words, ‘maintaining a thesis at all costs.'”
But there are some intriguing turns of argument here. One of them is: Dennett denies the full reality of the “world according to us.” That does seem implied by his manically consistent materialism. If we reverse the argument, though, perhaps there might be an argument along these lines: If “the world according to us” is real, then materialism is not true. Defending human experience entails battling materialism. And I have an inkling that an argument for the existence of God lies along that path somewhere.