Sam Harris speaks with Sean Carroll about our understanding of reality. They discuss consciousness, quantum mechanics, the arrow of time, free will, facts and values, and other topics. Sean Carroll is a theoretical physicist at CalTech. He received his PhD from Harvard University. He has worked on the foundations of quantum mechanics, the arrow of time, and the emergence of complexity. Carroll has been awarded prizes and fellowships by the National Science Foundation, NASA, the Alfred P. Sloan Foundation, the David and Lucile Packard Foundation, the American Physical Society, the American Institute of Physics, and the Royal Society of London. He frequently serves as a science consultant for film and television. He is the author of The Biggest Ideas in the Universe: Time, Space, and Motion. Twitter: @seanmcarroll   Episodes that have been re-released as part of the Best of Making Sense series may have been edited for relevance since their original airing.