There are entirely too many brilliant people on this board. Nearly all the time my own opinion is being expressed in a far more lucent fashion than I could possibly express it by multiple people before I even read half of the thread. Hence my being mostly relegated to lurker status nowadays.
But, if only for the sake of exercising some of the old synapses and the possibility that I might add something even remotely novel, I'll say a few words.
The following is the woefully unstructured rantings of an INTP. Beware!
I do not think that self-interest and altruism are necessarily contradictory. If I wish to help others because doing so makes me happy or gives me fulfillment, then in reality I am being both self-interested and altruistic. For most people, it seems, the two necessarily go hand in hand. Why we are hardwired this way is beyond me, although I have my suspicions, but that this is the essential nature of the vast majority humans seems quite obvious to my eyes.
Many would have me believe otherwise. They paint human life in black and white, dumbing down what truly is an amazing mosaic of colored complexity. They would have me believe that the human desire to be happy and fulfilled is necessarily evil - that the only means towards which we can become "good" is to deny this desire entirely. And, although much of my experience of such people lies within the halls of conservative Christendom, I have found that this unnecessarily pessimistic view of human nature finds its home in persons of many different world views.
I think that it is a vile thing to portray human nature in such a fashion, and I have a very difficult time dealing with those who espouse such a position. I cannot imagine the amount of wasted potential of those who have followed this credo, damning themselves to a lifetime of hating their own desires - and thus their very selves. (For what is the self without desire I wonder? )
Thankfully, this attack on self-interest seems rarely taken to its logical extreme. The self-same laziness that allows a person to be blind to the complexity of the issue also seems to keep them from exploring the necessary ends of their position. In this I take solace.