Guildenstern: Do you think Death could possibly be a boat?

     Rosencrantz: No, no, no... Death is not. Death isn't. Take my 

                  meaning? Death is the ultimate negative. Not-being. 

                  You can't not be on a boat.

    Guildenstern: I've frequently not been on boats.

     Rosencrantz: No, no...what you've been...is not on boats.