> This morning I declined to write a popular article about the question "Can machines think?" I told the editor that I thought the question as ill-posed and uninteresting as the question "Can submarines swim?". But the editor, being a social scientist, was unmoved: he thought the latter a very interesting question too.

http://www.cs.utexas.edu/users/EWD/ewd08xx/EWD854.PDF

So that's where that's from! A friend had a variant of this quote somewhere, he may have put it up on his bedroom wall. It took me years to understand the analogy between the two questions and what the author even meant was a problem. Maybe I have partly the brain of a social scientist. :-)