Chickens

Isaac:  “If a tree fell on a chicken, that would be funny.”
Richard: “But that would hurt the chicken.”
Isaac: “You have to have a brain to get hurt.  Chickens aren’t alive!”
Richard: “Yes they are.”
Isaac: “No they aren’t!  Chickens are made from ingredients, and they don’t put hearts in!”
Richard: “I’m pretty sure they are alive.”
Isaac [stomps off with indignation]: “Richard!  Sometimes you are too silly to talk to!”