Marcus Aurelius called them the “touchstones of goodness.”

Courage.

Temperance.

Justice.

Wisdom.

To millions, they’re known as the cardinal virtues, four near-universal ideals adopted by Christianity and most of Western philosophy, but equally valued in Buddhism, Hinduism, and just about every other philosophy you can imagine. They’re called “cardinal,” C. S. Lewis pointed out, not because they come down from church authorities but because they originate from the Latin cardo, or hinge.

It’s pivotal stuff. It’s the stuff that the door to the good life hangs on.

Like the Cardinal directions, the four main points on the compass—north, south, east, west—the four virtues are a kind of compass. A guide to what to do, who to be, how to behave, how to respond in every situation—with:

Courage, bravery, fortitude, honor, sacrifice…

Temperance, self-control, moderation, composure, balance…

Justice, fairness, service, fellowship, goodness, kindness…

Wisdom, knowledge, education, truth, self-reflection, serenity…

These are the key to a life of excellence, in every sense. “If, at some point in your life,” Marcus wrote, “you should come across anything better than justice, prudence, self-control, courage…if you find anything better than that, embrace it without reservations—it must be an extraordinary thing indeed.” That was almost twenty centuries ago. We have discovered a lot of things since then — automobiles, the Internet, cures for diseases that were previously a death sentence — but have we found anything better?

No, we have not. It’s unlikely we ever will.

So memorize those four virtues. Act on them. Live them. Tell everyone you meet about them. And keep them close to your heart always.