Lifeboat

Imagine a lifeboat with about 6 billion people, but with enough provisions for 11 billion. What would be good reasons to throw people off the lifeboat? I can think of two. First, to protect ourselves from violent people. Second, to protect ourselves from those who deliberately do damage to the boat or the provisions.

The only other reason to throw people overboard is to make the rest of us feel better. To make us feel safer - throw them overboard before they do the same to us. Or to protect ourselves from alien beliefs and practices. Or, so we can ensure ourselves a larger share of the provisions.

If we viewed the earth as a lifeboat, perhaps we'd be thankful for life itself, and be less likely to see the necessity of throwing other people overboard. We'd be less likely to think that the deaths of others were "worth it" to achieve our ideological, religious, or economic goals. None of us want to be sacrificed for another's cause, so why would we want to sacrifice others?