If you want to master something, teach it.

Your gaps reveal themselves through teaching

We often think mastery comes from private practice—closing the door and perfecting something alone. But there's something honest that happens when you have to explain what you know to someone else. Suddenly the gaps show up. You realize which parts you actually understand deeply and which parts you've just memorized or gotten comfortable with. Teaching forces clarity in a way that solo practice doesn't.

This matters beyond obvious cases like tutoring. When you explain your thinking to a friend, write about your hobby, or mentor someone at work, you're doing something counterintuitive: you're actually accelerating your own learning. The person asking questions—even naive ones—is doing you a favor. They're poking at the soft spots. They're asking you to justify things you've stopped questioning. That friction is where real understanding lives.

The twist is that this works best when you're not trying to impress anyone. The most learning happens in conversation, not in presentation mode. When you're willing to say "I don't know" or "that's a good question, let me think about it," you're using teaching as a tool for yourself. Mastery isn't something you then graciously share. It's built through the sharing itself.