Kavka's Toxin

Kavka's toxin puzzle is another paradox, this time created by the moral philosopher Gregory Kavka in 1983.

Here it is described in his own words:

An eccentric billionaire places before you a vial of toxin that, if you drink it, will make you painfully ill for a day, but will not threaten your life or have any lasting effects. The billionaire will pay you one million dollars tomorrow morning if, at midnight tonight, you intend to drink the toxin tomorrow afternoon. He emphasizes that you need not drink the toxin to receive the money; in fact, the money will already be in your bank account hours before the time for drinking it arrives, if you succeed. All you have to do is. . . intend at midnight tonight to drink the stuff tomorrow afternoon. You are perfectly free to change your mind after receiving the money and not drink the toxin.

(He can tell whether or not you intend to drink the poison with a high-tech machine that he has. If you really need a justification for thought experiments, then the back story is that he's trying to test out the machine. That still doesn't make much sense, since he's paying you a lot, and he didn't really need to pick a toxin, but he's eccentric. The weirdo.)

The problem: can you fully intend to drink the poison if you know that you don't have to? You'll always know that you don't reallllly have to drink it.... but if you think that, then you won't get the money.

I think that the solution is to intend to drink it regardless of whether or not you get paid. Then you'll get paid. The only flaw is that you then won't have to drink it.... ....and you'll know that earlier.... so you won't fully intend to drink it.

I guess you'll have to drink it, be violently ill for a day, and get a cool million in cash

Side note: Wikipedia also gives a real-world example of the puzzle: the Political Manifesto.

"Before an election, a political party will release a written document outlining their policies and plans should they win office. Many of these promises may be difficult or impossible to implement in practice. Having won, the party is not obligated to follow the manifesto even if they would have lost without it. In this example, the Electorate is the equivalent of the Billionaire, the Manifesto Promise the equivalent of the intention to drink the toxin and implementing the policies is equivalent to drinking the toxin." ~Wiki

I found this funny because of that last bit: to politicians, implementing promised policies is equivalent to drinking toxin. Hehe.