Economists talk endlessly. They teach; they give seminars; they brainstorm, argue, and chat with each other in the office, on the phone, and in the hotel lobby during their incessant conferences. All this talk is not "just talk." If everything could be said in writing, economists would not need to waste time with seminars or spend money for trips to conferences. Students could take graduate courses by correspondence in the comfort of their homes. But if one assumes that economists and their students are rational, they apparently gain from talking with each other face to face.