Philosopher and author Rebecca Newberger Goldstein discusses her new book, The Mattering Instinct, which argues that our lives are a quest to validate our inherent self-centeredness. Tracing this essential longing from physics and biology through to ethics and politics, she explains to EconTalk's Russ Roberts why material success alone can never satisfy our deep-seated need to matter. She describes the four ways people seek significance--through transcendence, social connection, excellence, or competition--and explains how the unmet need to matter is at the heart of some of the biggest problems afflicting modern societies: loneliness, extremism, and polarization.