The answer from Psychoanalysis is that the making conscious of what you refer to as "the conflict between our social and tribal instincts and our relentlessly selfish and domineering instincts" will also produce the answer. Because the desire of desire itself is to maintain desire at all costs, in other words to maintain the Gaze of The Other no matter what. The relentless and domineering instinct is ultimately directed towards one thing: The love and acceptance of The Other. I guess as Zoroastrians we never saw egoism and altruism as opposites. This would make perfect sense to a Lacanian psychoanalyst. So the problem is not the conflict itself, but that the vast majority of people are unaware of the conflict and even more so of its profound structure.
2009/11/17 Special Kain
Zoroastrian freedom is the freedom of choice which is the freedom towards something: the freedom to choose and participate creatively. But liberation also means to become free from something oppressing and inhibiting, that is «the liberation of the human body and the fulfillment of its full potential». Unfortunately, I'm not Hegelian enough to claim that it's a dialectic relationship between the negative (the freedom from) and the positive (the freedom towards). The former doesn't have any positive substance, which is so important to Zoroastrian and civilizationist ethics!
You have to aspire after something, whether that's contributing to one's community and helping to expand it all across the globe or playfully creating new and exciting identities. There are two sides to Zoroastrian ethics: the sober and grown-up part is concerned with defeating evil and promoting social justice and tolerance (what Richard Rorty celebrated as political philosophies, see Jürgen Habermas, John Rawls and John Dewey), the playful and childish part is concerned with our identities us becoming «creativity machines» (what Richard Rorty celebrated as the philosophies for private use only, see Friedrich Nietzsche, Martin Heidegger, Michel Foucault and Jacques Derrida). Rorty's solution was the liberal ironist, Peter Sloterdijk's solution are neo-Nietzschean trans-human beings (thanks to genetic engineering and new ICTs).
But the question is whether such solutions can actually dissolve the conflict between our social and tribal instincts and our relentlessly selfish and domineering instincts. The freedom towards X has to convey and promote other people's freedom towards their X's as well. And this is where we meet liberal democracies. And now it's becoming clear why Gilles Deleuze so correctly pointed out that thinkers like Baruch Spinoza prosper in liberal and democratic communities. In this sense happiness is the freedom to prosper! And Zoroastrianism is the philosophy of blazing joys and mirth that Nietzsche anticipated in his later writings as the solution to our society's nihilism and cynism.