This is the conclusion of Bertrand Russell’s chapter on the influence of the philosopher John Locke, from his History of Western Philosophy:
“Enlightened self-interest is, of course, not the loftiest of motives, but those who decry it often substitute, by accident or design, motives which are much worse, such as hatred, envy, and love of power. On the whole, the school which owed its origin to Locke,, and which preached enlightened self-interest, did more to increase human happiness, and less to increase human misery, than the schools which despised it in the name of heroism and self-sacrifice. I do not forget the horrors of early industrialism, but these, after all, were mitigated within the system. And I set against them Russian serfdom, the evils of war and its aftermath of fear and hatred, and the inevitable obscurantism of those who attempt to preserve ancient systems when they have lost their vitality.”
John Locke inspired some of the most important parts of the U.S. Constitution; I think it would be fair to say that one of the unwritten foundations of the U.S. Constitution is enlightened self-interest. We are now in an age when enlightened self-interest is deprecated in favor of naked self-interest. The big philosophical question now is whether the Constitution can survive when the prop of enlightened self-interest is removed.