Astrophysicist Neil deGrasse Tyson returns for this episode of Rationally Speaking, with a particular question to discuss: Should he call himself an atheist?The impetus is a recent dust-up over Neil's appearance on Big Think , in which he explained that he avoids the label "atheist" because it causes people to make all sorts of unflattering (and often untrue) assumptions.Julia and Massimo reply with some counterarguments, and along the way delve into the philosophy of language.Neil's picks: The movie "Gravity," " IFLS ," and the TV Shows "The Big Bang Theory," "CSI" and"NCIS."