Consider the case of political dissidents in repressive countries - they deliberately take a public course of action, which they know full well will result in them and possibly their friends & family being arrested, jailed for years (usually decades), tortured and so on. And furthermore, they know that the odds of them being successful in their lifetimes are quite low (and that their chance of reaching that point is lowered significantly by being jailed, beaten, malnourished or executed). Yet each generation, there are large numbers of such dissidents around the world. Even if there is some kind of personal pyschic satisfaction in 'fighting for good', only someone who has never actually endured any meaningful pain in their life, or thinks dissidents have radically different nervous systems and physiology to the rest of us, could possibly think that the net result of this course of action would be anything other than extremely negative for the individual. The vast majority of people give up their friends and families to certain death, in the face of prolonged torture - that's how painful and unendurable it usually is. No possible balance of pleasure and pain, once torture is introduced, could result in a net positive outcome, when judged purely by self-interest. The only conclusion then, is that other motivations, such as self-sacrifice in pursuit of a higher ideal, or values beyond the individual, are what swing the balance and allow people to resist in such harsh conditions. So it's clearly wrong to say that all people are motivated strictly by self-interest. Not only that, it is a most irrational, delusional, self-justifying argument - the type made by people who are more interested in performing logical contortions in order to avoid having to change their mind one iota, than in finding out the truth about human nature and reality. Bear that in mind next time you hear some evo-psych, objectivist, or other reductionist argument.