As Jonah Lehrer chronicles here, altruism has always been a sticky subject for evolutionary biology. The first Darwinian explanation held that so-called "altruism" was actually a sham - ultimately, just another means of furthering the species; then, in the 1960s and 70s, the argument was moved to a genetic level, partially thanks to works like Richard Dawkins' "The Selfish Gene." That has been the reigning paradigm for some time, but it has never fully resolved the tension between altruism and natural selection, and now the discussion has exploded again thanks to some significant recantations.

Very probably, science can shed a great deal of light on some of the types of altruism we see in the world - a parent's love for a child or relative, or even a patriot's love for country, perhaps. With that said, the current scientific debate seems to be overlooking two important factors of sacrifice - love and morality - the ideas that might compel a person to feel that they should sacrifice themselves for others. As such, it's worth remembering what Jesus had to say on the issue: when asked by a scribe "who is my neighbor?" Jesus responded by telling the story we now know as "The Good Samaritan." The point? While evolutionary biology tries to figure out why we would sacrifice for anyone, Jesus calls us to sacrifice for everyone. Good luck finding a Darwinian explanation for that.