TommyP asks: How does Hamilton's Rule (Br - C > 0) of altruism relate to human society? I've heard it said that for me to give my life for a brother, it should actually require 2 brothers (or 8 cousins). What's different about humans that allows us to cheat and give our own life for a single, unrelated life?
I believe the rule you are referring too is stated as such: A Hamilton should never battle a Burr when life is on the line. But I have no idea what that equation you stated has to do with it. As far as cheating, it is unlikely that either of the contestants cheated. But they certanly were selfish. Pfft, getting shot at just for the sake of 'honor.' What a waste, as you mentioned if it had been for two of his brothers, or 8 cousins, or even 4 nephews, then it may have been justified. The rules are slightly more difficult when it comes to women folk, because as Grumpy pointed out in Snow White, they have "wiles, wicked wiles." As a result it typically only takes one mother, or one sister to set the whole thing in motion. As far as unrelated lifes, this typically requires money. See, humans are the only animals that use money, and for enough of it you can get most anyone to do most anything. But back to the brother cousin thing, yes, it is not very worth while to go for a 1:1 exchange.
There is quite a bit of theory behind this, and it is typically called Kin Selection. William Donald Hamilton studied this phenomenon before contracting malaria in Africa while trying to link AIDS to oral polio vaccines, and subsequently dying. Well, that is all for this time, hope you have a large family, just to make it worth while if you ever need to expire for the greater good.