Philosopher and skeptic Massimo Pigliucci discusses the "demarcation problem" in the philosophy of science, which is how to tell what is science and what is not science, and what is pseudoscience. He talks about Karl Popper's theory of falsifiability, comparing Einstein's theory of general relativity with Freudian psychoanalytic theory. He draws a distinction between theories that are "unscientific" and theories that are merely "false," and talks about Newtonian mechanics in this regard. He explains in what way astrology is more scientific than String Theory. He explains to what extent people, including the skeptics community, should just "trust consensus science," and when the public should get a "second opinion" when given bad news by scientists regarding public controversies such as human caused global warming. He argues that there are not actually two sides to some of these issues. He explains what it means to be a skeptic, and argues what responsibilities skeptics have regarding the promotion of consensus science. He explores why libertarianism may fuel global warming skepticism. And he details five questions to ask when evaluating someone's expertise.