Here I'd like to contrast two other answers. Joseph LeDoux said,
I believe that animals have feelings and other states of consciousness, but neither I, nor anyone else, has been able to prove it.In contrast, Nicholas Humphrey said,
I believe that human consciousness is a conjuring trick, designed to fool us into thinking we are in the presence of an inexplicable mystery. Who is the conjuror and why is s/he doing it? The conjuror is natural selection, and the purpose has been to bolster human self-confidence and self-importance—so as to increase the value we each place on our own and others' lives.If you believe, as I do, that human consciousness is a simple (or perhaps not so simple but at least a direct) extension of animal consciousness as LeDoux does, Humphrey's position makes no sense. Certainly animal consciousness didn't evolve just in order to build human consciousness out of it just in order to fool human beings into believing we are supremely important. Whether or not human consciousness has the effect of encouraging us to self-aggrandizement — and thereby perhaps enhancing our changes of survival — it makes no sense to me to attribute the existence of human and animal consciousness to that effect.
As these answers illustrate, though, we are far from understanding consciousness. My view is that the term consciousness starts us off on the wrong track. The term consciousness has too much of a sense of self-awareness and conceptualization about it. The real mystery is subjective experience in general.
We all live in our own worlds of subjective experience — and it's amazing that we so frequently forget that subjective experience is just what occurs within our heads. Subjective experience may or may not have a connection to the world outside our heads. Most likely it does; otherwise we would be hard pressed to survive. But fundamentally, all our experiences, including all our perceptions, all our thoughts, and all our feelings, occur within our heads. We do ourselves a disservice when we forget it.
On the other hand, since subjective experience is all we have, we rightly value our subjective experiences and those of others. Otherwise, where would we be?
I agree with LeDoux that our subjective experience is similar to that of animals. We don't know how either of them works; we don't even know how to think about subjective experience in a useful way. But to say that subjective experience is nothing more than a conjuring trick seems much too dismissive for me.
Next Friday, Gerald Edelman will be giving the Jacob Marschak Memorial Lecture at UCLA. I regret I won't be able to be there. From what I've read Edelman knows more about consciousness than just about anyone. He calls his view Neural Darwinism. The following is taken from an interview with him from last Summer. (Edelman didn't participate in the Edge question.)
The most important thing to understand is that the brain is "context bound." It is not a logical system like a computer that processes only programmed information; it does not produce pre-ordained outcomes like a clock. Rather it is a selectional system that, through pattern recognition, puts things together in always novel ways. It is this selectional repertoire in the brain that makes each individual unique, that accounts for the ability to create poetry and music, that accounts for all the differences that arise from the same biological apparatus—the body and the brain. There is no singular mapping to create the mind; there is, rather, an unforetold plurality of possibilities. In a logical system, novelty and unforeseen variation are often considered to be noise. In a selectional system such diversity actually provides the opportunity for favorable selection.