If a p-zombie is posited to be possible, then we have to explain how non p-zombie species (ourselves, at the very least) could have evolved. Which we cannot do, because p-zombies by definition have all the same behaviors as humans. When we contemplate a p-zombie, we might have a vague notion in the backs of our minds (perhaps influenced to by a long line of science fiction AI characters) that a p-zombie would not strive as hard to survive because it doesn't experience subjective pain, or would not be as successful mating or nurturing because it doesn't experience subjective feelings of love, but that cannot actually be the case given how p-zombies are defined. The p-zombie must be every bit as adapted for fitness in all areas including those, or else we'd be able to distinguish them objectively, which would be a contradiction. Which, as I said, means there can be no selection for conscious brains over p-zombie brains.
The proto-consciousness field hypothesis has an analogous problem. If there is no difference in behavior between an organism with a brain that's evolved to interact strongly with the field and one that whose brain does all the same neuro-synaptic pulse frequency switching but does not interact with the field, and both kinds of brain are possible, then there's no reason for the former to have evolved.
There are only two ways to go from there. One is straight into "Scientific Creationism" style arguments: consciousness (whether inherent in the functioning of the brain as in the p-zombie thought experiment, or involving an unknown physical interaction with an unknown field as in the proto-consciousness field thought experiment) is so improbable that it can only be reasonably explained by intervention of some other intelligence. Except in this case the argument is actually a valid one, because we explicitly do not have evolution "climbing Mt. Improbable" for us as an explanation.
The other is to reject the premise that (in the first case) a p-zombie is possible or (in the second case) that a brain that generates the full range of human behavior without interacting with the field is possible.
I much prefer the latter resolution. But in the case of the pc-field hypothesis that leads to a dead end. If the interaction with the field is a necessary by-product of the brain doing what it does to generate the behaviors that give us adaptive advantages, then all we can do is study the "what it does" and "how what it does generates our behaviors" questions as we're already doing. Subjective awareness in and of itself has no adaptive advantage to look for, and no dedicated structural adaptations toward that characteristic to find or examine. Furthermore, our understanding of what actually causes consciousness is not advanced at all; we've gone at best from not understanding how brain function causes consciousness to how the field (or interaction with the field, or whatever generates the field) causes consciousness. And that new mystery cannot even be studied, since we have no way to detect or test the field. And if, as many researchers claim, we actually have made progress in understanding how brain function causes consciousness, then it's an even worse deal, abandoning that progress and taking a big step backward, on no evidence.
