Indulge me in a thought experiment:

An atheist and another man are on a cruise ship, far removed from anybody else on the ship.

The man, who is a stranger to the atheist, accidentally falls over the railing and into the water.

What motivates the atheist to try and prevent the man from drowning?

(It doesn't matter how the atheist helps, whether he throws him a life preserver, calls ship crew to help, or dives in after him - so long as he put forth the effort to help save his life)

Other urls found in this thread:

businessinsider.com/two-year-old-hit-by-car-in-china-2011-10
en.wikipedia.org/wiki/Bystander_effect#Notable_examples
aeon.co/essays/do-we-need-a-telepathy-machine-when-we-already-have-empathy
cbc.ca/news/canada/the-bystander-effect-1.1059522
twitter.com/SFWRedditVideos

To save the man's life so he can go on living the one life he's got to live.

People generally don't like letting other people die because it would make them sad

goodness

Human nature.

AKA Empathy which is a natural human emotion/trait.

Unless he is 1 out of 100 human sociopath... Well then you are fucked.

Biologically and culturally ingrained altruism, mirror neurons, and the rational expectation of future reciprocity

His sense of morality innate to all humans.

The atheist isn't entirely removed from Christianity.

If we're implying that he was a westerner, he was still brought up in a society that was influenced by Christian morals for centuries. I don't know how much of it is biological and how much of it cultural, though.

What does Christianity have anything to do with this scenario?

I don't know. Would a Chinese tourist who was an atheist or a communist do anything?

I suspect some would.