Further to the previous post --
Nor can the physically-minded, mechanically-minded Darwinian monist(*) cannot provide an adequate explanation for how thoughts can be truly "ours", and not just part and parcel of the same physics-chemistry-biology chain of cause-and-effect that took us from the slime to the sublime.
If we are nothing more than the end-result of such a mindless, mechanical (think "mechanism") process, then surely are thoughts are as well. Our thoughts are nothing more than emanations of mindless biomechanical brain-firings -- no different in essence from the mechanical universe emitting a shooting star or a cow emitting a bolt of methane. Thoughts: Darwinian Mind-Burps™.
Darwinists love to subject reality to an infinite, seamless, unbroken string of cause-effect "mechanisms". Everything has to have a physical cause and and be the result of a mere "mechanism". This is why the sufficient cause of thought is beyond their explanatory tool-kit. If physical, it is surely beyond the thinker's ultimate control; at base, it is a biochemical action and nothing more. And, push-come-to-shove, hard-materialists admit exactly that. There is no immaterial soul inside the human machine causing the brain synapses to fire.
This is also why, e.g., they deny free-will. If the universe is a closed system of purely physical cause-effect mechanisms, there is no room in it for either free thought or free-will. (You may recall the guy in Expelled exclaiming, "there is no such thing as free will!" -- this explains the background to his outburst.)
Now, everyone who agrees with his assessment, raise your hand!
Whether you raised your hand or not is of little consequence -- the impulse to either raise your hand or leave your hand unraised was not caused by "you" as a truly free action of a free-will endowed agent, but, ultimately, by the seamless web of a cause-effect physical, mechanical universe.
Materialists resist real agency. Once we admit that agency is part of the furniture of reality, we move a step away from the comforting thought of a purely physical mechanical universe in which we are are our own gods, i.e., "Brights", and move a step closer to the admission of the real possibility of Agency, which, in the case of origin of life and origin of species, may resist being reduced to mere physical "mechanisms".