niko-time said:
"Is it always possible to balance the interests of self with the interests of others?"
The idea of a balance only really makes sense if its a balance between two kinds of things. How can you ever have a balance between a little of something over here and a lot of it over there? One outweighs the other by definition.
A better way to look at this is as a balance beween two kinds of natural and complementary action - competition vs cooperation. Both are clearly good in themselves, and even better when mixed appropriately in balanced fashion within a sociological (or even biological) system.
Competition could be defined as local self-interest. It is in the interest of any part of a system to compete, to strive creatively. And it is also healthy for a system as a whole to be a collective of active players (rather than a collection of dopes waiting around for instructions).
But equally, at the group or global level, it is naturally good that there is cohesion, co-operation, shared goals - a set of constraints in common. Constraints act top down, from the larger to the smaller scale. And even for individuals, "enforced" cooperation is something for the good. At least, in general, in the long run.
So it is easy to see that self-interest and group-interest can be in balance if they are viewed as two opposed, but also complementary, kinds of action. You don't want too much of either - either competition, or cooperation - but some balance that is "just right".
Now what counts as just right? Most people would probably think a system that is stable and adaptive - a society organised so that it lasts even despite perturbations (like weather events, outbreaks of aggression, and other disruptions).
And there are even models of these kinds of systems - like "edge of chaos" models that maintain an optimal balance of stability and plasticity (cooperative cohesion and competitive changeability).
These models in turn would allow you to measure actual societies I would suggest. You could take something like a measure of social inequality such as the Gini coefficient and say something about where the actual balance lies.
Are the statistics gaussian (indicating perhaps a society that is too static, too homogenous - wealth in a hunter/gather society, for instance, would probably be rather bunched around the mean)? Or are the statistics powerlaw (indicating a society that is open, with wealth and poverty over all scales - and perhaps less than ideal for the opposite reason)?
So in summary, it seems easy enough to model a system which can find a balance. But then the next question becomes, what optimal setpoint should that balance be striking?