First, one doesn’t have to be a materialist (or even a naturalist) to think abstract thought has a natural explanation. I’ve laid out a pretty detailed positive case elsewhere for the evolution of abstract thought and language, yet I’m a theist. (It was published in a theological journal. Hmmm.)
Second, all of the above applies to consciousness too, although my published work was specifically applied to conscience rather than consciousness. But it’s the same concept: the self reflecting upon itself. It’s an exponential curve: long and relatively flat until it reaches an inflection point and takes off. Animals and early hominins represent long, slow growth in the capacity. Sapiens around 100,000 years ago took a step forward in language and symbolic representation, and the curve shot upwards to present-day levels (reached at least 30,000 years ago).
I agree with all those things, though I haven’t explicitly made the case in writing. I agree with Middleton that humans are a “complex unity” rather than a duality of body/soul, and the individual human destiny is to die and be buried with the hope of resurrection to an embodied life on a renewed Heaven and Earth, not the disembodied soul’s “beatific vision” of God lasting for eternity.