It's a dream. The origin of this theory, a racist man, will factor into your acceptance or rejection of the theory. It does mine. I reject it, but not because of science, not entirely. I reject it because of my beliefs, my feelings.
Science is faith in doubt.
According to Popper, the explanation that always works is no explanation at all. I think that's a very good answer. I don't presume to know the right one, but I'm interested in my classmates' opinions about it. I like that.