"There is no evidence whatever to suggest that souls or spirits exist as anything other than metaphors or artifacts of the mind."
Yes, there is. Hence my disagreement with you in your assertion that there is no souls or spirits. It could be a result of our evolutionary instincts passed down through the ages, which gives us reason and logic. For that is the best way to survive, as man tries to subjugate beast, and has found that fit to pass down. I was just reading Doyle's "The Lost World" and have found that in the book, how the "indians" defeat the hominids through superior brainpower and tame the dinosaurs.
We have a spirit. That is how I am thinking and typing this at this very moment. How else would we be able to do this?
"I think, therefore I am," as Descartes said.