Well, I'm not disagreeing with the conclusion. My point was to do with logic. Hume argued that morals aren't to do with logic alone, but are made up mostly of non-rational motives. So, I want to help someone out of empathy, and perhaps - as you say - because I recognise that there is a contradiction between valuing my own life and not valuing another in a social system where each of us is mutually dependent. However, this contradiction is not of a purely logical nature - like saying "2 + 2 = 5". The conflict comes at an emotional an empathetic level. I come to understand that others are beings like me who feel pain and suffering, and I DESIRE to ease their pain in recognition that it could be mine.
So, self-contradiction, perhaps, but in a limited sense. There is nothing logically self contradictory about valuing yourself and not others. It's the "free-rider" problem, isn't it: if everyone stole, then there would be no such thing as property; but what if only I steal? There is no problem, then.
