In this episode of Rationally Speaking, Julia and Massimo talk to physicist and climatologist Michael Mann about how we know the climate is getting warmer. Among other things, they cover the physical processes of climate change, the role that predictive models have played in confirming scientists' theories about the rate of warming, and what are uncertainties in the science. Also, how optimistic we should be about technological solutions to the problem. Dr. Michael E. Mann is Distinguished Professor of Meteorology at Penn State University, with joint appointments in the Department of Geosciences and the Earth and Environmental Systems Institute. He is also director of the Penn State Earth System Science Center. Dr. Mann is author of more than 160 peer-reviewed and edited publications, and has published two books including Dire Predictions: "Understanding Global Warming in 2008 and The Hockey Stick and the Climate Wars: Dispatches from the Front Lines" in 2012. He is also a co-founder and avid contributor to the award-winning science website RealClimate.org.

How has alternative medicine managed to become so mainstream? This episode of Rationally Speaking features Dr. Paul Offit, award-winning specialist in vaccines, immunology and pediatrics, and author of popular books such as "Do You Believe in Magic?: The Sense and Nonsense of Alternative Medicine." Julia and Massimo interview Dr. Offit about the fight against alternative medicine, why it's still unregulated, and whether or not to tell patients about placebos.

On this episode of Rationally Speaking, Massimo and Julia survey the present, past, and future of skepticism. Special guest Kendrick Frazier, editor of Skeptical Inquirer, talks about how the movement's focus has changed and what the frontiers of skepticism should be. Kendrick Crosby Frazier is a science writer and editor of Skeptical Inquirer magazine for over 30 years. He is also a former editor of Science News, author or editor of ten books, and a Fellow of the American Association for the Advancement of Science.

In this episode of Rationally Speaking, Julia and Massimo turn their attention to connoisseurship -- or snobbery, depending on your point of view! Fine wines, bottled water, high-end audio equipment -- what all these have in common are passionate customers who are discriminating enough to pay top dollar for subtle differences between options. Or are they? This episode explores the evidence on whether connoisseurs can really tell the difference between, for example, the $7 wine and the $700 one -- or whether it's a distinction without a difference.

Looking for love online? You're not alone -- one in five new relationships nowadays begin on a dating site. But just how scientific are the "matching algorithms" sites like eHarmony and OKCupid use? What does cognitive psychology tell us about how this new choice context affects our happiness? Massimo and Julia turn an analytical eye on the math and science of online dating, in this episode of Rationally Speaking.

The next time you're kicking yourself for some stupid mistake, remember: Even history's genuises screw up! Astrophysicist and author Mario Livio joins this episode of Rationally Speaking to talk about his latest book, "Brilliant Blunders: From Darwin to Einstein - Colossal Mistakes by Great Scientists That Changed Our Understanding of Life and the Universe." Learn about why Darwin's theory of natural selection "shouldn't" have worked, why Einstein was confused about the role of aesthetics in physics, why Hoyle stubbornly refused to change his mind about a "steady state" universe -- and why those mistakes are central to scientific progress.

The podcast discusses naturalism, exploring its implications on free will, consciousness, and the meaning of life. It delves into the distinctions between ontological and epistemic reductionism, the impact of naturalism on morality, and the role of storytelling in understanding the universe. The conversation emphasizes the challenges in distinguishing between useful and useless philosophy.

Why does the universe exist? And is that even a sensical question to ask? Philosopher Jim Holt has written extensively for publications such as the New Yorker, the New York Times and Harper's, and most recently embarked on this "existential detective story" in his new book, "Why Does the World Exist?: An Existential Detective Story" Jim discusses his book with Massimo and Julia in this live episode of Rationally Speaking, taped at the 2013 Northeast Conference on Science and Skepticism in New York City.

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?

Just like love, motherhood, and apple pie, no one could be against fairness. No one, that is, except philosopher Stephen Asma, the author of "Against Fairness." Massimo and Julia sit down with Stephen in this episode of Rationally Speaking, to talk about what he thinks is wrong with the concept of fairness -- and about certain traditional values he thinks are more important.