Consciousness and Determinism
What relationship, if any, is there between the problems of subjective consciousness (in our sense) and the question of determinism; the question, that is, of whether or not there are other possible ways the world might have turned out? This question has something to do with both free will and how consciousness affects the physical world. This rather brief and tentative note will sniff around the edges of the question.
It certainly feels to me, subjectively, as though there are lots of other ways the world could have been; in particular, it feels as though I could have taken voluntary actions other than those that I did take, and that those other actions would have resulted in other states of the world. But it's not clear to me that I'm a particularly reliable judge on that score; I have no reason to think that I could not be wrong.
That is to say, while I cannot doubt or deny that I have subjective experience, I see no barrier to doubting or denying that that subjective experience could have gone differently. That is, for all I'm certain of, it might be that this particular stream of consciousness, this particular time series of subjective experiences, is the only one that I could have had (for meanings of "could" ranging over, for instance, physical possibility and logical possibility).
This does not seem to be the same question as the question of whether or not my consciousness affects the physical world; whatever the answer to that question, whether or not my subjective decisions affect that big bunch of atoms out there, it could still be the case that the subjective decisions that I in fact make are the only ones I could have made, or that they represent only one of billions of possible paths.
This also does not seem to be the same question, or not exactly the same question, as the question of whether or not the universe as a whole is determined. It might be for instance that the universe as a whole is not determined, but my subjective decisions are. It might be the case that some of the things that happen out there in the objective world are random (or otherwise nondetermined), but that given the ones that actually happened, the subjective experiences that I had and decisions that I made were the only possible ones. On the other hand, it could be (for all I know) that both the objective world and my consciousness are entirely determined, or that neither are. (The remaining case, that all the rest of the world is deterministic but my consciousness is not, is hard to imagine; not impossible, but it's hard to imagine how it would work.)
So just as it doesn't seem that a simple nondeterminism in the universe is enough to allow consciousness in (see the note on "explanation"), it also seems that that nondeterminism is not required for consciousness. Whether or not the universe is deterministic, and whether or not subjective consciousness is, the basic problems of consciousness remain.