Until we come up with a coherent idea of what we mean by causation, I say teachers should accept this on tests (via Saturday Morning Breakfast Cereal, one of my favorite webcomics):
It reminded me of the Simpsons episode “Much Apu About Nothing” in which Apu is finally taking the citizenship test. I couldn’t find a YouTube clip, but at least I found the quote I was looking for:
Proctor: All right, here’s your last question. What was the cause of the Civil War?
Apu: Actually, there were numerous causes. Aside from the obvious schism between the abolitionists and the anti-abolitionists, there were economic factors, both domestic and inter–
Proctor: Wait, wait… just say slavery.
Apu: Slavery it is, sir.
Or perhaps we could learn to phrase our questions better.