Cognitive Scientist, UC, Irvine; Author, Visual Intelligence
I believe that consciousness and its contents are all that exists. Spacetime, matter and fields never were the fundamental denizens of the universe but have always been, from their beginning, among the humbler contents of consciousness, dependent on it for their very being.
The world of our daily experience—the world of tables, chairs, stars and people, with their attendant shapes, smells, feels and sounds—is a species-specific user interface to a realm far more complex, a realm whose essential character is conscious. It is unlikely that the contents of our interface in any way resemble that realm. Indeed the usefulness of an interface requires, in general, that they do not. For the point of an interface, such as the windows interface on a computer, is simplification and ease of use. We click icons because this is quicker and less prone to error than editing megabytes of software or toggling voltages in circuits. Evolutionary pressures dictate that our species-specific interface, this world of our daily experience, should itself be a radical simplification, selected not for the exhaustive depiction of truth but for the mutable pragmatics of survival.
If this is right, if consciousness is fundamental, then we should not be surprised that, despite centuries of effort by the most brilliant of minds, there is as yet no physicalist theory of consciousness, no theory that explains how mindless matter or energy or fields could be, or cause, conscious experience. There are, of course, many proposals for where to find such a theory—perhaps in information, complexity, neurobiology, neural darwinism, discriminative mechanisms, quantum effects, or functional organization. But no proposal remotely approaches the minimal standards for a scientific theory: quantitative precision and novel prediction. If matter is but one of the humbler products of consciousness, then we should expect that consciousness itself cannot be theoretically derived from matter. The mind-body problem will be to physicalist ontology what black-body radiation was to classical mechanics: first a goad to its heroic defense, later the provenance of its final supersession.
The heroic defense will, I suspect, not soon be abandoned. For the defenders doubt that a replacement grounded in consciousness could attain the mathematical precision or impressive scope of physicalist science. It remains to be seen, of course, to what extent and how effectively mathematics can model consciousness. But there are fascinating hints: According to some of its interpretations, the mathematics of quantum theory is itself, already, a major advance in this project. And perhaps much of the mathematical progress in the perceptual and cognitive sciences can also be so interpreted. We shall see.
The mind-body problem may not fall within the scope of physicalist science, since this problem has, as yet, no bona fide physicalist theory. Its defenders can surely argue that this penury shows only that we have not been clever enough or that, until the right mutation chances by, we cannot be clever enough, to devise a physicalist theory. They may be right. But if we assume that consciousness is fundamental then the mind-body problem transforms from an attempt to bootstrap consciousness from matter into an attempt to bootstrap matter from consciousness. The latter bootstrap is, in principle, elementary: Matter, spacetime and physical objects are among the contents of consciousness.
The rules by which, for instance, human vision constructs colors, shapes, depths, motions, textures and objects, rules now emerging from psychophysical and computational studies in the cognitive sciences, can be read as a description, partial but mathematically precise, of this bootstrap. What we lose in this process are physical objects that exist independent of any observer. There is no sun or moon unless a conscious mind perceives them, for both are constructs of consciousness, icons in a species-specific user interface. To some this seems a patent absurdity, a reductio of the position, readily contradicted by experience and our best science. But our best science, our theory of the quantum, gives no such assurance. And experience once led us to believe the earth flat and the stars near. Perhaps, in due time, mind-independent objects will go the way of flat earth.
This view obviates no method or result of science, but integrates and reinterprets them in its framework. Consider, for instance, the quest for neural correlates of consciousness (NCC). This holy grail of physicalism can, and should, proceed unabated if consciousness is fundamental, for it constitutes a central investigation of our user interface. To the physicalist, an NCC is, potentially, a causal source of consciousness. If, however, consciousness is fundamental, then an NCC is a feature of our interface correlated with, but never causally responsible for, alterations of consciousness. Damage the brain, destroy the NCC, and consciousness is, no doubt, impaired. Yet neither the brain nor the NCC causes consciousness. Instead consciousness constructs the brain and the NCC. This is no mystery. Drag a file's icon to the trash and the file is, no doubt, destroyed. Yet neither the icon nor the trash, each a mere pattern of pixels on a screen, causes its destruction. The icon is a simplification, a graphical correlate of the file's contents (GCC), intended to hide, not to instantiate, the complex web of causal relations.
