Scientists and materialists often complain that religious believers commit the “God of the gaps fallacy.” This fallacy is committed when someone claims they have evidence for God by pointing to a gap in the scientific explanation of the universe. For example, if science can’t explain near death experiences, then some Christian might claim that a near-death experience is evidence that God exists. How else would we see such divine things before dying? The scientist is correct to criticize the believer if, in principle, science might some day explain the near-death experience.
When the believer does this he is, in a sense, acting irrationally, by jettisoning any sort of closed causal history of the physical universe (by essentially claiming miracles exist that occur right before we die). The believer has replaced scientific explanation with a mystical explanation or dogma.
But in some cases, people claim that some phenomena will never be explained by science, because it cannot be explained by science, in principle. The most prominent phenomenon of this type is consciousness. Consciousness (claim many Christians, non-materialists, and for a very ling time philosophical Hindus) cannot be explained in principle by science, because science operates by ignoring the phenomenal qualities of things being observed. If I want to know why hot sauce is so hot, I don’t think about what “hotness” is like, I put some hot sauce under a microscope and look for chemical correlations with other hot foods. But what do I do if I want to know how I experience anything at all? Can I study consciousness? I can’t separate consciousness from the way things appear to me, which means that science can’t account for it in principle, because science doesn’t even acknowledge what I am trying to explain in the first place.
I don’t know whether or not consciousness is evidence for God. But it does seem to be a valid argument that exploits a permanent “gap” in the scientific explanation of the universe. It is a sort of “God of the gaps argument” that is not only acceptable, but very interesting.