The Stoics were virtue ethicists. They saw virtue as the good, what was worth pursuing. As opposed to the Epicureans who pursued pleasure.

This makes Stoicism a worldly philosophy, outward facing philosophy. It’s focused on thought and action, not achieving internal ecstacy.

What makes virtue so good? It’s the optimal strategy in a risky and uncertain world. Consider this line from Seneca:

Cling tooth and nail to the following rule: Not to give in to adversity, never to trust prosperity, and always to take full note of fortune’s habit of behaving just as she pleases, treating her as if she were actually going to do everything it is in her power to do.

The last one warning is important. Here Seneca is telling us to take account of how uncertain and unreliable reality is. How do we do this?

The philosopher Epictetus analogizes life to a dice game:

The counters are indifferent; the dice are indifferent. How do I know what the cast will be? But to use carefully and dexterously the cast of the dice, this is my business.

Life isn’t completely random. We can influence the game. We do have significant control. But we get attached to many things outside of our control. Our social status, relationship, health, mortality. For Stoics these are indifferent. They are good, but now what life is ultimately about.

Life is closer to poker than chess or dice. In dice, you have no control over the outcome. In chess, if you play perfectly, you will achieve the optimal outcome in each game. In poker, you can play perfectly and still lose. But you can play well and win over the long term.

I’ve sat at tables where the flop comes out with terrible cards and the person sitting next to me groans at the fact that they folded their terrible hand. But they made the correct choice! Over the long term, folding terrible hands is the right call. Even though sometimes you’ll get “unlucky” and find out that you had the best hand.

In the world, the games of achieving wealth, health, and love are unreliable. You can do all the right things and still lose.

How does virtue fit in this picture? Here’s Massimo Pigliucci and Gregory Lopez in the Handbook of New Stoics:

Here is the great insight of the ancient philosophy of Stoicism: Shaping your character is ultimately the only thing under your control. So in order to exploit your good luck and cope with the bad luck, it is necessary to be a good person. Through a combination of rational introspection and repeated practice, you can mold your character over the long term.

In poker, you have control over whether you make the play with the highest expected value. In life, you have control over your actions and thoughts, your character. That is it. Focusing on character is the antidote to uncertainty.

If someone pours their heart into achieving wealth or social status, they are hostage to fate. Stoics on the other hand, are responsible for character alone. What is out of their control is indifferent.