Many people are wrongly turned off or on by Stoicism because they think Stoicism endorses a purely indifferent attitude towards the world. People who care very much about the human race and how societies and governments treat their people are especially turned off by apathy. Even more problematic are people who go into Stoicism thinking that apathy is the way of the Stoic and lazily read a few texts by Marcus Aurelius and Epictetus and think that the world is outside their control so why should they bother giving a helping hand or “being political”?
But it’s obvious to anyone who has studied Stoicism, with an actual desire to know it, that Stoicism has been political from the beginning. The ancient Stoics believed that human beings are social and political creatures and so should involve themselves in society and in public service. Zeno of Citium, in ancient Greece, endorsed a republic with no money, no temples (no religion), no hierarchies, and complete equality between the sexes. Moving onto the days of the Roman Republic and Empire, the Stoics took up many roles in schools (Epictetus becoming an ex slave founded his own school) and took up many roles in the political establishment (e.g. Cato the Younger).
I think the confusion over Stoicism endorsing apathy is a result of the doctrine of things indifferent. Stoic doctrine teaches that things external to our judgment/will, which are things like our reputation, our wealth, our health, how many friends we have, events in the world, and even random thoughts in our head, are indifferent. All externals are indifferent to our eudaimonic happiness. But that doesn’t mean Stoics shouldn’t care about externals at all. Everyone needs externals to at least live and use to pursue virtue. Also, externals are neither good nor bad, they’re just preferred or dispreferred. The pivotal point though is that the Stoics value virtue as the only ethically good thing. But if a Stoic is to live virtuously, a Stoic must practice all four virtues: moderation, courage, practical wisdom, and justice. Justice is the reason why Stoics aren’t apathetic. Justice means being kind and fair to yourself and your fellow persons. Justice means being an educator, helping the needy, being a good father or mother, being a good son or daughter. Justice comes in many forms.
Probably one last reason why people think Stoicism promotes apathy is over the word apatheia. The Stoics didn’t mean by apatheia that one should not have any concern for anything or anyone. Apatheia is a state of lacking pathe. What is pathe? It literally means suffering. Pathe results in misjudging externals such as wealth and health as ethically good and misjudging externals such as poverty and sickness as ethically bad. The Stoics knew that a lot of our suffering (pathe) is a result of over-valuing things that aren’t as valuable as virtue. According to the Stoics, if you follow the four virtues, that should be sufficient for eudaimonic happiness. Eudaimonic happiness is the kind of happiness that is generated internally by having an ethically motivated purpose. If you become eudaimonically happy, you are in a state of apatheia, you are free from pathe.
So that’s the big difference between apatheia and apathy. Apatheia just means an undisturbed state that results from being a good person for the sake of being a good person. Apathy just means not giving a shit about anything and probably making the world a worse place for yourself and everyone around you.