In a special live Rationally Speaking, taped at NECSS 2013, Julia Galef moderates a lively discussion between Massimo and Michael Shermer, head of the Skeptic Society and founding publisher of Skeptic Magazine. The topic: Can science tell us what is "moral"? This discussion comes after both men have tackled the question separately in books (Massimo's Answers for Aristotle and Michael's The Science of Good and Evil), and jointly in a recent debate on the Rationally Speaking blog. Questions under debate include: Does "natural" = "morally right"? How do we make tradeoffs between different people's happiness? And what role should science and philosophy play in making these decisions?