Introspection means talking to yourself, and one of the best ways of talking to yourself is by talking to another person. One other person you can trust, one other person to whom you can unfold your soul. One other person you feel safe enough with to allow you to acknowledge things—to acknowledge things to yourself—that you otherwise can’t. Doubts you aren’t supposed to have, questions you aren’t supposed to ask.
The American Scholar: Solitude and Leadership – William Deresiewicz. First sentence.