Discourses, What Solitude Is, and What Kind of Person a Solitary Man is

Epictetus — The Slave

But you still need to prepare yourself for being alone. You need to be able to rely on yourself and be your own companion. Zeus lives with himself and stays calm by himself. He thinks about how he runs things and what it all means. He keeps his mind busy with thoughts that matter to him. You should be able to do the same. Talk to yourself. Don't feel like you need other people around all the time. Don't be lost about how to spend your time. Watch how the universe works. Think about how you fit into everything else. Remember how you used to react to things that happened, and how you react now. What still causes you pain? How can you heal those things and get rid of them? If anything in your life needs work, fix it using reason.

Epictetus — The Slave Original

But none the less a man ought to be prepared in a manner for this also (being alone), to be able to be sufficient for himself and to be his own companion. For as Zeus dwells with himself, and is tranquil by himself, and thinks of his own administration and of its nature, and is employed in thoughts suitable to himself; so ought we also to be able to talk with ourselves, not to feel the want of others also, not to be unprovided with the means of passing our time; to observe the divine administration, and the relation of ourselves to everything else; to consider how we formerly were affected towards things that happened and how at present; what are still the things which give us pain; how these also can be cured and how removed; if any things require improvement, to improve them according to reason.