Kavka's toxin puzzle
Encyclopedia
Kavka's toxin puzzle is a thought experiment
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
and mutual assured destruction
.
A possible interpretation: Can you intend to drink the toxin, if you know you do not have to?
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: Whether you are paid or not, drinking the poison would leave you worse off. 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
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.
Thought experiment
A thought experiment or Gedankenexperiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences...
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
Deterrence theory gained increased prominence as a military strategy during the Cold War with regard to the use of nuclear weapons, and features prominently in current United States foreign policy regarding the development of nuclear technology in North Korea and Iran. Deterrence theory however was...
and mutual assured destruction
Mutual assured destruction
Mutual Assured Destruction, or mutually assured destruction , is a doctrine of military strategy and national security policy in which a full-scale use of high-yield weapons of mass destruction by two opposing sides would effectively result in the complete, utter and irrevocable annihilation of...
.
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 know you do not have to?
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 paradoxNewcomb's paradoxNewcomb's paradox, also referred to as Newcomb's problem, is a thought experiment involving a game between two players, one of whom purports to be able to predict the future. Whether the problem is actually a paradox is disputed....
, 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 willFree will"To make my own decisions whether I am successful or not due to uncontrollable forces" -Troy MorrisonA pragmatic definition of free willFree will is the ability of agents to make choices free from certain kinds of constraints. The existence of free will and its exact nature and definition have long...
. - 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 causationRetrocausalityRetrocausality is any of several hypothetical phenomena or processes that reverse causality, allowing an effect to occur before its cause....
. - 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.
| Intend | Do not intend | |
|---|---|---|
| Drink | 90 | −10 |
| Do not drink | 100 | 0 |
According to Kavka: Whether you are paid or not, drinking the poison would leave you worse off. A rational person would know he would not drink the poison and thus could not intend to drink it.
| Intend | Do not intend | |
|---|---|---|
| Drink | Impossible | −10 |
| Do not drink | Impossible | 0 |
David Gauthier argues once a person intends drinking the poison one cannot entertain ideas of not drinking it.
The rational outcome of your deliberation
tomorrow morning is the action that will be part of your life going as
well as possible, subject to the constraint that it be compatible with
your commitment-in this case, compatible with the sincere intention
that you form today to drink the toxin. And so the rational action is
to drink the toxin.
| Intend | Do not intend | |
|---|---|---|
| Drink | 90 | −10 |
| Do not drink | Impossible | 0 |
One of the central tenets of the puzzle is that for a reasonable person
- There is reasonable grounds for that person 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
- Mutually assured destruction
- Newcomb's paradoxNewcomb's paradoxNewcomb's paradox, also referred to as Newcomb's problem, is a thought experiment involving a game between two players, one of whom purports to be able to predict the future. Whether the problem is actually a paradox is disputed....
- Prisoner's dilemmaPrisoner's dilemmaThe prisoner’s dilemma is a canonical example of a game, analyzed in game theory that shows why two individuals might not cooperate, even if it appears that it is in their best interest to do so. It was originally framed by Merrill Flood and Melvin Dresher working at RAND in 1950. Albert W...
- DoublethinkDoublethinkDoublethink, a word coined by George Orwell in the novel 1984, describes the act of simultaneously accepting two mutually contradictory beliefs as correct, often in distinct social contexts. It is related to, but distinct from, hypocrisy and neutrality. Its opposite is cognitive dissonance, where...