Etta Place: [before riding the bicycle] Do you know what you're doing?
Butch Cassidy: Theoretically.
Butch Cassidy: Theoretically.
Etta Place : [before riding the bicycle] Do you know what you're doing?
Butch Cassidy : Theoretically.
http://www.moviequotedb.com/movies/butch-cassidy-and-the-sundance-kid/quote_4755.html