The Toxin Puzzle

Philosophers are good in inventing weird cases. Especially action philosophers are. Philosophers are serious people, so, of course, they don’t invent these cases just for the fun of it, although it can be a pleasure to invent them. No, they do it because they think that they have an important problem to solve or at least to raise. This problem is then discussed by other philosophers, and so they fill the pages of their journals and their books. Since I am also a philosopher – even more an action philosopher by origin – I like to read such cases and the discussions they bring with them, and to make my contributions to the debate, sometimes.

Recently I came across such a philosophical case, and I thought that it would be interesting to talk about it in my weekly blog. Here it is:

An eccentric billionaire, let’s call him Tramp, has offered you the following deal. He gives you a vial of toxin. If you drink it, it will make you painfully ill for a day, but will not threaten your life or have any lasting effects. Tramp 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 you are perfectly free to change your mind after receiving the money and not drink the toxin. (The presence or absence of the intention is to be determined by the latest ‘mind-reading’ brain scanner). You accept the offer. (Adapted from the original case by Gregory S. Kavka, see note)

So far so good, and nothing seems so easy as earning the money and become a millionaire. Is it? In the remaining part of his article Kavka discusses why it is not, for actually it is impossible to intend to drink the toxin. I’ll pass over the details, but the essence is this. A reasonable person can seriously and honestly develop an intention to perform a certain action but s/he cannot develop such an intention if beforehand s/he knows already s/he’ll not perform the action because of its nasty consequences. For it is part and parcel of an intention that you seriously have made up your mind to do what you intended, but before you have developed your intention you had already decided not to perform the action the intention involves. You cannot intend not to do what you intend.

The case just described has become known as the Toxin Puzzle. It’s a puzzle, because you are asked to form a simple intention to perform an action, which is a thing you every day do many times. Nevertheless now you are unable to form the intention. Kavka explains it this way. Intentions are not independent decisions but are related to an action. But the reasons for an action are a different thing, and just these reasons for the action are absent in the intention. Or to put it in a different way: The reason to intend are different from the reason to act in the toxin case. Therefore, so Kavka, “when we have good reasons to intend but not to act, conflicting standards of evaluation come into play and something has to give way: either rational action, rational intention, or aspects of the agent's own rationality (e.g., his correct belief that drinking the toxin is not necessary for winning the million).” (see note) We cannot have double rational standards.

The upshot is: You cannot intend to do what you know beforehand that you’ll not do. Or otherwise, you can only intend to do what you seriously and honestly want to do. If you have to abandon an intended action, this can only happen for reasons that are advanced after the intention has been formed and not if such good (and effective) reasons are already put forward beforehand. You cannot honestly say “I’ll do it”, while you know that you’ll not do it, unless you are irrational. That’s what this case is about.

Note

Gregory S. Kavka, “The Toxin Puzzle”, on https://www.law.upenn.edu/live/files/1298-kavka-g-the-toxin-puzzle-1983