At the end of the 19th Century, Frege invented a new language, based on mathematics, designed to help people reason more logically. His ideas have had a lasting impact on philosophy, math, computer science, and the study of artificial intelligence. And many of the questions that influenced his thinking are still hotly debated today: How much does language influence the thoughts you can think? Could there be a way of speaking that taps into deep philosophical insights about the nature of reality? What's the relationship between math and logic? Josh and Ray try to make sense of Frege with their old friend and host emeritus John Perry (who turns 81 on Tuesday), author of Frege's Detour: An Essay on Meaning, Reference, and Truth. Sunday, January 14 at 11 am.