(some disorganized thoughts)
Humans as a species are more altruistic for their in-group, and more warlike and distrusting towards the out-group, generally speaking. Altruism of the out-group sort of course exists and for obvious reasons should be embraced and encouraged as much as possible. But the fact is cooperation is stronger for the in-group.
Humanity will increasingly meet challenges that require world-wide cooperation. Sometimes that’s “their” problem will cease to merely be “their” problem and become an “ours” as in Humanity’s. The likes of global climate change and spreading disease create this unique type of problem our species hasn’t truly met with before. Meaning, people who think they have the answer are generally wrong if their answer is simple.
So, why not expand the in-group as much as possible? Why can’t humanity see those of the same species as brothers and sisters? There are various obvious reasons why not, including an upper limit to how many people can be truly believed to be in one’s in-group, and the likely need for a common enemy (so, the thing that unites humanity could be the most disastrous for it - an alien invasion!)
The other reason why expansion of in-groups or “extended families” is bad is a sort of in-group viciousness that also exists. Taboos, mores, and folkways (that is, the same thing but decreasing levels of intensity) are enforced by people in a culture upon others. The culture is a functioning machine, and when people defy boundaries the culture relies on, it is like running the machine in reverse, or without caster oil - very bad.
So people naturally try to squash out behavior they do not like in their own culture, meaning that an expanding in-group can create intolerance where none existed before! An American may respect the culture of Afro-Cubans from a distance, but may be horrified to have chickens beheaded to catchy music in his own neighborhood. He just might not put up with it.
Observe where fundamentalists (and I don’t mean just religious fundamentalists, but including religious fundamentalists) direct their shoulds. They don’t seem to mind that the ideals they spew were rejected by Europeans generations ago, and never adopted by countless world cultures in the first place. They feel a sense of ownership over their own culture (and related cultures, American cultures). Would their frustration become violent if they felt such an ownership over more cultures? This question might become less hypothetical with time.
So, I don’t believe we can tap directly into the human tendency to be altruistic with in-groups directly. We can, however, indirectly. Last century saw two world wars. But, it saw 28 seasons of the Olympic games. Koreans wished to exact revenge on the Japanese for the occupation. They have yet to fire a single missile that way, but South Korea is kicking Japan’s ass in semiconducters (though they have a long ways to go to catch up in other areas of course).
A strategy something like this might work: reduce need for destructive wars (they will never go completely away; human nature), such as by limiting overuse of resources (we are already having water wars! look at Darfur closely…) and create more and more situations in which the natural need for out-group wars creates a mutually-beneficial situation through innovation. In other words, the out-group hostility is so strong, I think it would be wrong to not harvest it like coal!
