Dean: (arguing that Rory can study while watching him play softball) You can look up from your Philosophy of Nihilism from time to time to see me play.
Rory: Yes, but what's the point?
Rory is making a joke that Dean doesn't get. The philosophy of Nihilism is nothing has a point. (or more formally put... the world, and especially human existence, is without objective meaning, purpose, comprehensible truth, or essential value)