David and Tamler break down the biggest question in moral philosophy -- can we derive value judgments from a set of purely factual claims? Like the Scottish Philosopher David Hume they're surprised when the usual copulation of propositions 'is' and 'is not' suddenly turn into conclusions in the form of 'ought' and 'ought not.' And what's the deal with all these copulating propositions anyway? Aren't they a little young for that?  Do propositions practice safe copulation?  Is proposition porn about to be the new fad? They also talk about Moore's Open Question Argument, which introduced the term "naturalist fallacy," and respond to angry criticism over last episode's Rationalia segment.     LinksListener C. Derek Varn's blog post: "The Dogmatic Slumber of Neil deGrasse Tyson" [symptomaticcommentary.wordpress.com]Hume's Moral Philosophy [Stanford Encyclopedia of Philosophy]Is-ought problem [wikipedia.org]GE Moore's Moral Philosophy [Stanford Encyclopedia of Philosophy]Open-question argument [wikipedia.org]The Naturalistic Fallacy [wikipedia.org]