I’ve come to think that the necessary and sufficient conditions of a good life are equanimity, community, and truth.

Equanimity means a good inner life, marked by something like happiness, satisfaction, or peace. Unless individuals achieve satisfactory inner lives, even a perfectly just society is a nightmare.

Community encompasses all valuable relationships among living things, from the baby on her parent’s lap to a fair and efficient economic order that integrates all seven billion people and does justice to the animals, as well. Love and justice are two of the virtues that turn relationships into communities.

By truth, I primarily mean knowledge about the way things actually are–empirical knowledge–because I would assign knowledge about the good to the other two domains.

These three principles are necessary because, unfortunately, they are not perfectly compatible. If they were harmonious, we could perhaps reduce the list to a single underlying principle. But alas, truth can make equanimity and community harder. Relating well to others can undermine internal peace. Valuable relationships sometimes depend on fictions. These and other tensions among the three principles partly explain why it is so hard and rare to achieve a good life.

The three principles are sufficient because other good things are only good insofar as they benefit the three. For example, beauty is probably necessary for a rich and satisfying inner life; good communities possess and produce certain kinds of beauty; and the truth is sometimes beautiful. But beauty can also be false, unjust, or distressing. Insofar as beauty does not support truth, community, or equanimity, its pursuit is no part of a good life.

How do I reach these conclusions? Not by way of arguments from first principles. Arguments are made within the three domains, not in favor of them. For instance, all large societies need the rule of law and individual rights, among other things. That is the kind of conclusion that can be grounded in evidence and reasons–but one must assume that it matters whether communities are good, in the first place. If you deny that justice toward others has any relevance to you, no argument can prove that it should. (Here I draw on Bernard Williams’ Ethics and the Limits of Philosophy.)

The same is true of truth. Nietzsche liked to demonstrate that the pursuit of truth was a choice. If one makes that choice, the scientific method commends itself. If not, there is no argument for the scientific method. Finally, reasoning about how to achieve equanimity is fruitful, but there is no argument for seeking it in the first place.

Despite the lack of arguments for the three principles, all three tend to emerge in rich and mature traditions, from ancient India to the Hellenistic Mediterranean to modern Europe and many other places, even when someone tries to deny one of the three. For example:

Classical utilitarians defined the goal of life as pleasure and argued that a society could maximize the pleasure of its members by getting its markets and laws right. In other words, they dispensed with equanimity and relied only on community and truth. But the young John Stewart Mill blamed his depression on that oversight and developed a richer account of utilitarianism in which equanimity regained its independent standing and was no longer a mere consequence of community.

Certain anarchists and libertarians, such as Ayn Rand, have denied the virtues of community. But I once heard the libertarian philosopher Loren Lomasky compare libertarians who ingest Rand to snakes who eat pineapples. Rand takes a while to pass through the system, and you are better off when she is gone. A more sophisticated libertarian, such as Friedrich von Hayek, begins by recognizing that people are social animals, intrinsically connected to one another and needing strong ties for happiness and welfare. Hayek simply criticizes the state as a buttress of community, arguing that governments lack adequate information and trustworthiness to make beneficial decisions. In other words, community returns to libertarianism once one reflects more maturely.

The post-structuralist generation in France raised serious questions about truth. But I doubt that authors who mainly debunked truth (like Derrida and Baudrillard) will last. What will continue to matter is Foucault’s long and hard struggle for truth. To be sure, Foucault asked whether truth was always just a function of power, and thus made science and reason seem more problematic than they had seemed before. Yet his intellectual biography shows a constant pursuit of truth; that was the impetus for his skeptical questions in the first place. The world was obdurate for Foucault; he would not simply ignore it. The virtue he defended in his late (1983) lectures was parrhesia, speaking truth in the face of danger–in other words, truth that upsets equanimity.

The constant return of three principles (even when smart people try to dispense with them) suggests that they are deeply rooted in human experience. Yet it is wishful thinking to believe that they coexist easily. Our struggle is to pursue all three.