The Torturer's Dilemma: Analyzing the Logic of Torture for Information

virtuous cycle where the state is able to gain information from torture and increase the proportion of
knowledgeable captives in the pool; and a vicious cycle where misinformation leads the state farther
and farther afield, driving knowledgeable captives out. But only one of these equilibria should be
stable: as the virtuous cycle deepens, and the probability that the state is torturing a knowledgeable
captive increases, the state will eventually reach a point where it is no longer credibly able to play the
necessary strategy of torturing when the captive appears to lie, and imprisoning when he appears to tell
the truth – leading knowledgeable captives to lie, and the state to accept misinformation. And since the
state does not know when it has accepted misinformation when it does not play according to the signal,
the end result will be a rapid slide downwards into misinformation.
This model explains why we see the explosive cycle of denunciations in the continental witch-
trials of the 16 th and 17 th Centuries, as well as the Albigensian inquisition of the 13 th Century. In the
case of witchcraft, the state's (or inquisition's) priors were by definition faulty – believing that witches
exist, and that only torture could bring them to confess and name their confederates. Because there
could be no empirical evidence of witchcraft – that is, of the covenant with Satan, the attendance at the
Witches' Sabbaths, or of the use of magic – the inquisition would never find itself in a position where it
would know with certainty that it had erred. In the case of heresy, the lack of any evidence other than
confessions meant that the process would take in a larger and larger pool of suspects, regardless of guilt
- even though the conspiracy in this case was real. The model also provides us with an explanation for
why torture fails: torture depends on an investigative apparatus to separate truth from fiction – but
historically torture has been most likely to be used in cases where that apparatus is either difficult or
impossible to utilize. We would therefore predict that the more a situation involving torture
approximates this condition, the more likely it is to devolve into a cycle of denunciations, marked by an
increase in the number of captives over time. If the theory is incorrect, then torture should lead to a
decreasing number of captives, as the ignorant are winnowed out, and the members of the conspiracy
are wound up.
2.5. Evaluating the Model through Case Studies
Any statistical evaluation of how well torture works would be hamstrung from the start by the
deliberate lack of systematic information on how states torture: states, even when they do gather such
information, have no incentive to make it publicly available and even if they did they would have no
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