Ken walks into a restaurant.

WAITER: Good afternoon, sir. The specials today are roast lamb and baked trout.

KEN: I’d like the lamb, please.

WAITER: I almost forgot. We also have lobster thermidor.

KEN: In that case, I’ll have the trout, please.

What standard property of decision-making is Ken violating? (Hint: reread the section on Arrow’s impossibility theorem.) Is Ken necessarily being irrational? (Hint:

what information is revealed by the fact that the chef is able to prepare lobster thermidor?)