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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Causal decision theory | 2/2 | https://en.wikipedia.org/wiki/Causal_decision_theory | reference | science, encyclopedia | 2026-05-05T14:37:31.280571+00:00 | kb-cron |
=== Vagueness === The theory of causal decision theory (CDT) does not itself specify what algorithm to use to calculate the counterfactual probabilities. One proposal is the "imaging" technique suggested by Lewis: To evaluate
P
(
A
>
O
j
)
{\displaystyle P(A>O_{j})}
, move probability mass from each possible world
w
{\displaystyle w}
to the closest possible world
w
A
{\displaystyle w_{A}}
in which
A
{\displaystyle A}
holds, assuming
A
{\displaystyle A}
is possible. However, this procedure requires that we know what we would believe if we were certain of
A
{\displaystyle A}
; this is itself a conditional to which we might assign probability less than 1, leading to regress.
=== Counterexamples === There are innumerable "counterexamples" where, it is argued, a straightforward application of CDT fails to produce a defensibly "sane" decision. Philosopher Andy Egan argues this is due to a fundamental disconnect between the intuitive rational rule, "do what you expect will bring about the best results", and CDT's algorithm of "do whatever has the best expected outcome, holding fixed our initial views about the likely causal structure of the world." In this view, it is CDT's requirement to "hold fixed the agent’s unconditional credences in dependency hypotheses" that leads to irrational decisions. An early alleged counterexample is Newcomb's problem. Because your choice of one or two boxes can't causally affect the Predictor's guess, causal decision theory recommends the two-boxing strategy. However, this results in getting only $1,000, not $1,000,000. Philosophers disagree whether one-boxing or two-boxing is the "rational" strategy. Similar concerns may arise even in seemingly-straightforward problems like the prisoner's dilemma, especially when playing opposite your "twin" whose choice to cooperate or defect correlates strongly, but is not caused by, your own choice. In the "Death in Damascus" scenario, an anthropomorphic "Death" predicts where you will be tomorrow, and goes to wait for you there. As in Newcomb's problem, we postulate that Death is a reliable predictor. A CDT agent would be unable to process the correlation, and may as a consequence make irrational decisions: Recently, a few variants of Death in Damascus have been proposed in which following CDT’s recommendations voluntarily loses money or, relatedly, forgoes a guaranteed payoff. One example is the Adversarial Offer: "Two boxes are on offer. A buyer may purchase one or none of the boxes but not both. Each of the two boxes costs $1. Yesterday, the seller put $3 in each box that she predicted the buyer not to acquire. Both the seller and the buyer believe the seller’s prediction to be accurate with probability 0.75." Adopting the buyer's perspective, CDT reasons that at least one box contains $3. Therefore, the average box contains at least $1.50 in causal expected value, which is more than the cost. Hence, CDT requires buying one of the two boxes. However, this is profitable for the seller. Another recent counterexample is the "Psychopath Button":
Paul is debating whether to press the ‘kill all psychopaths’ button. It would, he thinks, be much better to live in a world with no psychopaths. Unfortunately, Paul is quite confident that only a psychopath would press such a button. Paul very strongly prefers living in a world with psychopaths to dying. Should Paul press the button? According to Egan, "pretty much everyone" agrees that Paul should not press the button, yet CDT endorses pressing the button. Philosopher Jim Joyce, perhaps the most prominent modern defender of CDT, argues that CDT naturally is capable of taking into account any "information about what one is inclined or likely to do as evidence". Caspar Oesterheld and Vincent Conitzer have argued against the use of causal decision theory when applied to Newcomb's paradox. They argue that there exist multiple scenarios where the use of causal decision theory cause the agent to voluntarily lose money, and that causal decision theorists are subject to diachronic Dutch books.
== See also ==
== References ==
== External links == Causal Decision Theory at the Stanford Encyclopedia of Philosophy The Logic of Conditionals at the Stanford Encyclopedia of Philosophy