As a teacher, my aim is to help others think for themselves. Philosophy is an activity, not a body of doctrine to be passively absorbed. In philosophy, everything is up for grabs, if – and it’s a big if – you have a good argument. Tradition and authority count for nothing; that may be one reason philosophers sometimes get banished, burned at the stake, or invited to drink hemlock. For me, philosophy is most enjoyable as a collaboration, as we test, develop, revise, and question each position that comes our way. There’s no sitting on the sidelines: everyone is responsible for joining in the collective project.