Those who change from a purely physicalist/materialist view of reality to some kind of nonphysicalist/nonmaterialist stance, including scientists, often report that their change was due, at least in part, to a profound personal experience: a state of Grand Oneness, a Universal Unity with All Reality – usually triggered by psychedelics or deep meditation, or perhaps by an out-of-body or near-death experience.
I, too, have had a personal experience. But my case, oddly, was something of the reverse. How could a personal experience lead to a greater appreciation of the purely physical world as a candidate for ultimate reality and as an explanation of phenomenal consciousness? What could that possibly be?