Foreword by Steven Pinker A philosopher shows how to rid ourselves of breaks in logic that cause destructive thinking and extremism, and provides the tools to inoculate our minds and keep them safe from becoming infected by bad ideas. Why do people reject science and believe conspiracy theories they see on social media? How do people become so radicalized online that they commit acts of violence? Why is our society so politically polarized? How has a growing percentage of Americans become unhinged?