Robert Wright who runs Bloggingheads.tv writes Darwinism isn't depressing in IHT:
...survival machines are unfairly maligned. The name suggests, well, machines devoted to their survival. In truth, though, natural selection builds machines devoted ultimately to the survival of their genes, not themselves.Hence love. A love-impelled grandparent sacrifices her life to save a child's life. Too bad for the grandparent, but mission accomplished for the love genes: They've kept copies of themselves alive in a vibrant vehicle that was otherwise doomed, and all they've lost is a vehicle that, frankly, didn't have the world's most auspicious odometer anyway. Love of offspring (and siblings) is your genes' way of getting you to serve their agenda.
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Transcending the arbitrary narrowness of our empathy isn't guaranteed by nature. (Why do you think they call it transcendence?) But nature has given us the tools - not just the empathy, but the brains to figure out how evolution works, and thus to see that the narrowness is arbitrary.