To get a free copy of the Infectious Generosity book, visit ted.com/generosity Will McCaskill is a moral philosopher and the cofounder of the Effective Altruism Movement, a school of thought that tries to answer the question: How can we do as much good as possible? Chris and Will talk about how to use evidence to figure out how to help solve the world’s most pressing problems efficiently. Then, they discuss why focusing our efforts on some issues over others is both a compelling philosophical question — and a complex project to scale up. Transcripts for The TED Interview are available at: go.ted.com/TTIscripts