The Nothing Behind Everything

This episode of Radiolab features two segments exploring complex concepts about the nature of reality and the universe. The first segment delves into the idea of multiple universes, featuring a discussion between Robert Krulwich and physicist Brian Greene, who debate whether the existence of multiple universes challenges the possibility of understanding everything and whether the fundamental laws of physics apply to all universes. They discuss how the concept of multiple universes might change the questions physicists ask and whether the math that describes our universe can be applied to others. The second segment explores the fundamental nature of reality, questioning whether the world is made of "stuff" or if it's more like an expression of rules or math. Robert Krulwich and Jad Abumrad discuss these ideas with Jim Holt, the author of "Why Does the World Exist?", touching on concepts from atomism to quantum field theory, and whether the solidity we perceive is merely a product of mathematical relationships.