How deep do the categories we use to navigate the world go? Are they more transient than we normally think? In episode one of the new season, Ben and Aaron lay the groundwork for the series "Race: Is That a Thing?"

In this episode we meet Armand Marie Leroi, Prof. of Evolutionary Developmental Genetics at Imperial College, London, who caused a stir regarding "race" 13 years ago with a controversial op-ed piece in the New York Times.