Topher,
Your approach to these issues is interesting because although you follow orthodox scientific attitudes almost to a tee, you do acknowledge the evidence for Ψ. Clearly you think Ψ can be stuffed into the scientific picture with very little disruption, whereas I don't.
The problem is that there are two kinds of scientific explanation operating here. There are large areas where the facts are well established and basically beyond contradiction, unfortunately there also seem to be substantial areas where the explanation is little more than an educated guess. You tend to back all the standard guesses, whereas I am a bit more suspicious. Which approach is closer to the mark, only time will tell, but it is important to distinguish between scientific facts and orthodox scientific assumptions. In my opinion, here are some of the latter:
The assumption that consciousness is a phenomenon associated with nets of neurons. This may have seemed obvious once, but the fact that learning of whatever kind can be found in single celled creatures should raise a question mark - as should the fact that anaesthetics do the same thing for us and single cells. As you point out, other non-neuron systems, such as the immune system, can also learn, but that hardly seems to weaken my point. I am less inclined to split hairs over different types of learning/consciousness, because I just don't think enough is known to do that properly.
The idea that the definition of living is akin to the definition of a planet - i.e. more or less arbitrary. Clearly there is no 'elan vital' in organic chemicals, but that does not in any way rule out the possibility that there is a spirit component to life - not a metaphor, but something real.
As indicated above, I am suspicious of the all embracing explanatory power of complex systems and emergent phenomena.
Vague concepts with enormous explanatory power are potentially dangerous because they lull us into believing that we understand more than we do.
Science has, of course a standard explanation for all things Ψ. Various psychological traits, such as the desire to find order where there is none, statistical artifacts, various unrecognised uses of the senses, etc. All these explanations can be found in textbooks, but they are guesses, and in this case even you accept that they are wrong.
The conventional explanation of NDE's - that dying neurons short of oxygen and poisoned by glutamate, go on a final spree of activity - seems like a classic guess. Uncontrolled nervous signalling isn't really likely to generate a meaningful experience - people don't get beautiful halucinations from epileptic seaisures (correct me if I am wrong), or strokes - indeed these things tend to induce a period of amnesia.
Another assumption is that the entire blueprint to create an animal is stored in its DNA. Maybe the blueprint is stored in a spirit/morphic field form. Sheldrake certainly knows about HOX genes, and could spout the standard explanations if he wanted to - but he is not convinced. The facts here are that DNA contains the blueprints for the proteins components for cells, plus some regulatory mechanisms. The assumption that this is the entire blueprint is speculation. The surprisingly small number of human genes - about 30000, I believe - most of which we share with a wide range of other creatures - might hint in Sheldrake's direction.
Of course, if part of our blueprint is spiritual, that opens up some interesting questions about natural selection - but we have been there before
I don't want to assert belief in any of the above concepts - I don't really do belief - but I think that it is important not to swallow orthodox guesses totally uncritically.
David