In 2011, Sean Carroll wrote an essay on why — from a science perspective — our minds must be extinguished at death
Rapid eye movement may indicate neural activity, but dreaming for me implies a conscious awareness of the dream state, which I consider as unlikely in spiders.
Something immaterial can’t have an effect on the material realm, presumably, so how would it be selected as advantageous by Darwinian natural selection?
A materialist view of reality leaves out much of reality (love, reason, mercy, truth, etc.) so skittish materialists often call themselves “physicalists.”