Must a "theory of everything" include consciousness?

Marking the century anniversary of Einstein’s first major contributions, an article in Nature (433, 257 – 259, January 2005) surveyed some of the world’s top physicists on the current status of a “Theory of everything”.  Roger Penrose remarked that such a theory must include consciousness. Here is his statement:

 

The terminology 'theory of everything' has always worried me. There is a certain physicist's arrogance about it that suggests that knowing all the physical laws would tell us everything about the world, at least in principle. Does a physical theory of 'everything' include a theory of consciousness? Does it include a theory of morality, or of human behaviour, or of aesthetics? Even if our idea of science could be expanded to incorporate these things, would we still think of it as 'physics', or would it even be reducible to physics?

As for myself, I perhaps have enough of the physicist's arrogance about me to believe that a physical 'theory of everything' should at least contain the seeds of an explanation of the phenomenon of consciousness. It seems to me that this phenomenon is such a fundamental one that it cannot be simply an accidental concomitant of the complexity of brain action. It must be of such sophistication that the brain is enabled to dig more deeply into the fundamental workings of the Universe than are more commonplace physical systems. And if this is so, then we are very much farther from a proper understanding of the laws of nature than most physicists seem to believe.

Indeed, irrespective of the consciousness issue, in my opinion, we are nowhere close to an accurate, purely physical theory of everything. I find it remarkable how many physicists will express the view that, despite some missing details and unifying concepts, we know virtually all we need to know to describe the fully detailed physical behaviour of systems — at least in principle. Yet, there is at least one glaring omission in present physical theory. This is how small-scale quantum processes can add up, for large and complicated systems, to the almost classical behaviour of macroscopic bodies. Indeed, it is not just an omission but an actual fundamental inconsistency, sometimes referred to as the measurement paradox (or Schrödinger's cat). In my view, until this paradox is resolved we must necessarily remain very far from a physical theory of everything — whether or not such a theory exists.

Roger Penrose