Kavka's toxin puzzle is a
thought experiment
A thought experiment is an imaginary scenario that is meant to elucidate or test an argument or theory. It is often an experiment that would be hard, impossible, or unethical to actually perform. It can also be an abstract hypothetical that is ...
about the possibility of forming an intention to perform an act which, following from reason, is an action one would not actually perform. It was presented by moral and political philosopher Gregory S. Kavka in "The Toxin Puzzle" (1983), and grew out of his work in
deterrence theory
Deterrence theory refers to the scholarship and practice of how threats of using force by one party can convince another party to refrain from initiating some other course of action. The topic gained increased prominence as a military strategy d ...
and
mutual assured destruction
Mutual assured destruction (MAD) is a doctrine of military strategy and national security policy which posits that a full-scale use of nuclear weapons by an attacker on a nuclear-armed defender with second-strike capabilities would result in ...
.
The puzzle
Kavka's original version of the puzzle is the following:
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.
A possible interpretation: Can you intend to drink the toxin if you also intend to change your mind at a later time?
The paradox
The paradoxical nature can be stated in many ways, which may be useful for understanding analysis proposed by philosophers:
* In line with
Newcomb's paradox, an
omniscient pay-off mechanism makes a person's decision known to him before he makes the decision, but it is also assumed that the person may change his decision afterwards, of
free will
Free will is generally understood as the capacity or ability of people to (a) choice, choose between different possible courses of Action (philosophy), action, (b) exercise control over their actions in a way that is necessary for moral respon ...
.
* Similarly in line with Newcomb's paradox; Kavka's claim, that one cannot intend what one will not do, makes pay-off mechanism an example of
reverse causation.
* Pay-off for decision to drink the poison is ambiguous.
* There are two decisions for one event with different pay-offs.
Since the pain caused by the poison would be more than off-set by the money received, we can sketch the pay-off table as follows.
According to Kavka: Drinking the poison is never to your advantage regardless of whether you are paid. A rational person would know he would not drink the poison and thus could not intend to drink it.
David Gauthier argues once a person intends drinking the poison one cannot entertain ideas of not drinking it.
One of the central tenets of the puzzle is that for a reasonable person
* There is reasonable grounds for that person to intend to drink the toxin, since some reward may be obtained.
* Having come to the above conclusion there is no reasonable grounds for that person to drink the toxin, since no further reward may be obtained, and no reasonable person would partake in self-harm for no benefit.
Thus a reasonable person must intend to drink the toxin by the first argument, yet if that person intends to drink the toxin, he is being irrational by the second argument.
See also
*
Doublethink
Doublethink is a process of indoctrination in which subjects are expected to simultaneously accept two conflicting beliefs as truth, often at odds with their own memory or sense of reality. Doublethink is related to, but differs from, hypocris ...
*
Prisoner's dilemma
The prisoner's dilemma is a game theory thought experiment involving two rational agents, each of whom can either cooperate for mutual benefit or betray their partner ("defect") for individual gain. The dilemma arises from the fact that while def ...
References
External links
Levy, Ken (2009). "On the Rationalist Solution to Gregory Kavka's Toxin Puzzle." Pacific Philosophical Quarterly 90, 267–289.
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Decision-making paradoxes
Puzzles
Thought experiments in philosophy
1983 introductions