It is a matter of self identification only. The thing that allows inhumanity towards man is the idea that he, she, or they, are not me or mine. We have a native prohibition against self destruction.
I have to agree. I don't really have anything else to add cause I feel like Skip pretty much covered it. It's a survival instinct. Even giving pertains to some sort of selfishness. Would you do it if it didn't benefit you in some way? Even if it's just to feel good?
I disagree. You don't work because you have to work. You work because you have to eat, but there are plenty of ways to eat without working. However, you want to eat because it is in your self-interest to not die.
I thought about this and do think there are people that do things because they feel it is the "right thing to do" but do not get any joy of doing it. There are people that are selfless. Now there may be a subconscious need to do the action ...