toxin puzzle a puzzle about intention and practical rationality posed by Gregory Kavka. A trustworthy billionaire offers you a million dollars for intending tonight to drink a certain toxin tomorrow. You are convinced that he can tell what you intend independently of what you do. The toxin would make you painfully ill for a day, but you need to drink it to get the money. Constraints on the formation of a prize-winning intention include prohibitions against ‘gimmicks,’ ‘external incentives,’ and forgetting relevant details. For example, you will not receive the money if you have a hypnotist ‘implant the intention’ or hire a hit man to kill you should you not drink the toxin. If, by midnight tonight, without violating any rules, you form an intention to drink the toxin tomorrow, you will find a million dollars in your bank account when you awake tomorrow morning. You probably would drink the toxin for a million dollars. But can you, without violating the rules, intend tonight to drink it tomorrow? Apparently, you have no reason to drink it and an excellent reason not to drink it. Seemingly, you will infer from this that you will eschew drinking the toxin, and believing that you will eschew drinking it seems inconsistent with intending to drink it. Even so, there are several reports in the philosophical literature of (possible) people who struck it rich when offered the toxin deal! See also ACTION THEORY, INTEN- TION , PRACTICAL REASONIN. A.R.M.