Sam Harris speaks with David Edmonds about the life and philosophy of Derek Parfit. They discuss Parfit’s work on identity, time bias, the “non-identity problem,” population ethics and “the Repugnant Conclusion,” the ethical importance of future people, Effective Altruism, moral truth, and other topics. David Edmonds is a Distinguished Research Fellow at the Uehiro Centre for Practical Ethics at Oxford University and a former BBC radio journalist. He is the author or editor of many books which together have been translated into over two dozen languages. His books include (with John Eidinow) the international best seller Wittgenstein’s Poker and, most recently, a biography, Parfit: A Philosopher and his Mission to Save Morality. David is also the host of a couple of philosophy podcasts including Philosophy Bites, which he creates with Nigel Warburton. Twitter: @DavidEdmonds100 Website: www.davidedmonds.info   Learning how to train your mind is the single greatest investment you can make in life. That’s why Sam Harris created the Waking Up app. From rational mindfulness practice to lessons on some of life’s most important topics, join Sam as he demystifies the practice of meditation and explores the theory behind it.