What the Solipsist Means

When you are lonely, you have time to think; and one thing you may think of is the privacy of the mind, our ineluctable opacity to one another. One mines the pit of isolation for insight, seeking the metaphysical in the mundane—or hidden depths within oneself. “I think, therefore I’m not you.”

You might expect a philosopher like me to celebrate these meditations. But I suspect that they’re a form of sublimation: the animal reality of frustrated social need refigured as tragic epiphany, like referred emotional pain. We’re ashamed to confess that we feel lonely, so we say we’re doing philosophy. But the philosophy is skewed. Why fixate on the privacy of the mind when the body is no less private? “Why can one man not piss for another man?”—a question posed by my mother-in-law with a long-suffering shrug. It is no easier—in fact, it may be harder—than thinking for someone else.

Earlier this year, the private notebooks of Ludwig Wittgenstein were published in English for the very first time,…