The Art of True Friendship — Letters from a Stoic

If a wise man is truly self-sufficient, why does he need friends at all? Letter 9 is Seneca's careful answer to that question. He starts with the Stoic position, the sage needs nothing, lacks nothing, is complete in himself. Then he complicates it. A wise man seeks friendship not out of need but out of desire: he wants someone to whom he can give what he has, someone he can teach, someone he can benefit. The distinction matters.

Needing a friend makes you dependent. Wanting one makes you generous. He addresses the objection directly, if your friend dies and you grieve, haven't you proven that you needed him after all? His answer is that grief over loss is natural; it's a different thing from being unable to live without someone. You can replace what you had before by forming a new friendship.

The capacity doesn't die with the person. The letter also skewers a kind of false self-sufficiency, the person who withdraws into themselves, declares the world worthless, and lives a solitary life they dress up as wisdom. That isn't strength. That's retreat dressed as philosophy. Seneca closes with a line from the Stoic Stilbo, who lost his city, his wife, and his children to war and declared himself unharmed.

Everything that was truly his, he still had. That's the real meaning of self-sufficiency.