Pain, placebo, and cognitive penetration

There is compelling evidence that pain experience is influenced by subjects' cognitive states such as expectations and beliefs. In this paper, we explore one specific form of such influence, namely placebo analgesia, and examine its relevance for a debate in philosophy of mind and cognitive science the cognitive penetration of perceptual experience. In short, this refers to the epistemologically problematic influence of a subject's beliefs, expectations, and desires on their perceptual experience. We begin by summarising the cognitive penetration debate, and single out as particularly important a form of cognitive influence on experience that we term Radical Cognitive Penetration. We go on to argue at least some cases of placebo analgesia constitute compelling instances of Radical Cognitive Penetration and are resistant to debunking explanations. Nonetheless, we urge caution in extrapolating from the cognitive penetration of pain experience to broader conclusions about the cognitive penetration of perceptual experience. Instead, we suggest that the cognitive penetration of pain experience raises distinctive psychological, epistemological, and ethical issues of its own.