Given a choice between ending selfishness and ending stupidity, I always used to prefer and sometimes brashly spoke for ending stupidity. In my arrogance, I considered intelligence the master of reflex and emotion: a proper amount of reflection should lead anyone to adjust their grabbing and self gratifying ways toward the more sustainable relationship with friends and fellow citizens. Thought alone is one tool available to poorest human, I reasoned. The benefits of a yielding consideration of others seemed to me almost as evident as the shorter term benefit of taking for number one whatever was not nailed down and a little meditation would pull you over to the benign.
Now I see selfishness more often as betraying fear: it is the constant practice and the general response of those who think, or more accurately: feel, they won't have enough to get by sooner or later. And while there is a bit of theory to the effect that we may have inborn inclinations toward or away from altruism that vary from person to person, I know it is experience, especially in childhood, that determines our expectations of want. Those experiences are compounded later in life by acquisition of goods and power: having "something to lose" often exacerbates the hostility toward the welfare of others when the sense of insecurity is falsely equated to possessions. And they are determined in ways that won't be changed, not even by a life of wealth and surplus. Surplus, in fact, is rarely defined in our society as having more than the minimum you need to get by, a minimum most of us above poverty cannot and do not want to reckon.
Working counter to that dynamic is the instilled sense of security or adequacy. And that sense can be as irrationally disconnected from one's finances and physical jeopardy as can its opposite fears. And it can be as unacknowledged even as it determines daily choices. That sense that one need not be overly worried about how they will fare next year may come from a constructive childhood where one was guided to experience their own adequacies or from a belief in a deity who watches out for us and imbues us with confidence and hope when we muster faith. Generosity is not so much a matter of having the material wherewithal to give.
I also used to believe that of those two choices, stupidity was more realistically vulnerable to education and exercise of the mind whereas "curing" selfishness seemed to require some unattainable magic. I do not feel so sure of these things now.
Adam Smith viewed the rules of commerce and the freedom to set prices and sell to the highest bidder as "the invisible hand", a benign and almost divine force inherent in the simple rules of the market. To this day, hundreds of years later, many hold with that incomplete vision and think it is all that is needed to account for the increase of wealth since the idea was set to paper. I say "incomplete" because we logged and mined and burnt the world to reach our present state of abundance. Do you deny that it is at best pockets of abundance amid fields of want...and getting more lopsided by the year? Smith was quite right in one thing: The simplest rules and the particular definition of fairness ["honesty in commerce", perhaps?] are all it takes to structure a social order in an economy. I look upon the divisions of wealth and their sick trend and upon the catastrophic one-sided way we share nothing with the earth that has so long given us whatever we wanted and I am certain the invisible hand is the right hand. It is time to change the rules so that the invisible hand is the left hand. Our present state of degradation and poverty in the shadow of towering wealth is not accidental or temporary. And unfortunately because selfishness is the prevailing spirit of the rules that structure humanity's dealings with itself, intelligence is the subservient trait, applied to devising efficiencies that benefit the well to do far more often than those who couldn't or didn't grab a bigger share for themselves.
I have no solution. The choice is a rhetorical device and actual accomplishment of either improvement seems to require magic. There is no magic.