I don't think there is a "human nature", except for our nature to exist, or being existence. All other human traits and behaviours are only accidental. They evolve due to circumstances in the environment. Or more genereally they have their existence in the relation to our enviroment. Greed has in my opinion come into being due to the limited availability of any given kind of object. From this limited availability a sense of posession arises, and consequently one will not simply give away what one posesses but will ask something in return. Eventually a kind of money will be used to trade, obviously for the sake of convenience. But it is not our nature to be greedy, but simply a reaction to the environment. Of course from a reaction something may be created, and then "we" would react again to the created thing, but this is just saying that some reactions can take on the form of a creation.
Maybe you have a different sense of the word nature, but to me it would refer to something that would come about in humans no matter what the circumstances during our evolution/history would be. I would not even be completely sure if I would call our "reactivity" human nature, because it only exists in relation [s:11qm7gf2]any kind[/s:11qm7gf2] to some sort of environment as well... Hmm, I guess this would eventually turn into the question of whether humans can only exist in relation to an environment :lol:
Anyway, imagine we could turn back time to when "modern" humans emerged, or alternatively imagine the human race getting wiped out, save for a lucky few. The kind of society that would evolve from these ancient modern humans, or this future human race, could be extremely different from our own, having different standards, different values, etc, in general, just a completely different way of living, as long as the circumstances are not roughly, if not exactly, the same as during our own actual human history. They wouldn't even have to resemble our way of living and thinking about the world.
The very reason why we could actually overcome greed and the use of money is because it is not in our nature..
--corrected a messed up sentence