Thanks for the detailed response. >It is also possible that humans have a greater intrinsic capacity for subjective experience independently of any cognitive p

Thanks for the detailed response. >It is also possible that humans have a greater intrinsic capacity for subjective experience independently of any cognitive process. I must disagree with you here - I would say that subjective experience is a cognitive process. Of course, this is a speculative opinion; but it seems likely to me: We know that we can have simple algorithmic and statistical processes on neural nets; we know we can build very complex processes from simple building blocks; we know the brain is full of neural nets; we know that the high level cognitive processes are build on the neural nets; and that if we interfere with the brain, we disturb the personhood. To me, this seems like a pretty good case for applying occams razor and deciding that the personhood comes from the (big, incredibly complex) neural nets. Loosely, I believe that if we could write a sufficiently powerful piece of software, and if we constructed it so that that was capable of complex introspection, then it would say it had a subjective experience. And I would tend to believe it. Such a feat is clearly some distance from the current state of the art and we have no idea how to do this - but still. >I think that current scientific theories are not capable of explaining the nature of sentience or of predicting which physical systems will be sentient and which not. I'm not sure if that makes me a supernaturalist or not. This is tricky territory. Its reasonable to believe our scientific theories are incomplete. Certainly, we have a long way to go, scientifically, before we understand how minds operate. But, lets look at our physics knowledge. Our physics models seem to be pretty good. Unless we are at very high energies, they seem to do a very accurate job of describing the world. We've built components with that knowledge, that have been reliable; our abstractions do not seem very leaky. It is important to realise, that while relativity did come along and wipe away aspects of the newtonian worldview, newtonian physics is still accurate for deciding where to throw the ball to get it into the net. The more detailed physics was only relevant when working with certain situations that demanded the lower level of abstraction. I don't believe nature evolved brains that require subtle properties of high energy physics to work. I'd say the systems underlying them aren't even quantum in nature. Some scientists would dispute this - notably Roger Penrose. But is evolution really going to build brains, and processing software - which are present, in some form, in a vast range of species - out of some mysterious quantum - or lower level - physics? Evolution tends to be about bootstrapping. Higher level systems are always assembled out of lower level building blocks. Thats why I have cells, tissues, organs - motifs and structure that repeat themselves. If you evolve a system that is sensitive to the smallest changes in the properties of its smallest units (quantum interactions, say) its much hard, in terms of the search required. It also is going to be much more fragile. Even neurons are a pretty high level construct, from a physics point of view; high enough so that our current physics probably models their functional characteristics completely. (Although we have yet to fully apply our current physics to analyse them completely; ANNs as we see them in AI are but the crudest approximations, and shouldnt be considered descriptive.). So I would tend to believe that we don't need any new physics to understand how minds work. If you are saying that there is some strange new physics needed to describe how the information relates to matter, then I think you are, functionally, a supernaturalist. I also put Penrose in that box, though, so its a personal opinion, and the jury is still out. If you think that there is a lot of science yet to be discovered, to come up with theories of how computational building blocks are made from neural architecture, and what the 'algorithms' that run on that architecture are, then I agree with you.