Of course he meets the differential operator after a short distance. The day of the lecture arrives and he eagerly goes to hear it. There are these two men travelling across the mountains in a hot-air balloon, and they have no idea where they are, due to fog. Well, his answer was a long time coming, it's completely correct, and it's absolutely useless. Biochemists think they're chemists.
Chemists think the're physical chemists.
Physical Chemists think they're physicists. Physicists think they're God. God thinks he is a mathematician.