How many universes are there? What has made us into who we are? Is there absolute truth? These are difficult questions, but mathematics has something to say about each of them. It can probe the physical reality that surrounds us, shed light on human interaction and psychology, and it answers, as well as raises, many of the philosophical questions our minds have allowed us to dream up. On this page we bring together articles and podcasts that examine what mathematics can say about the nature of the reality we live in.