Discussions concerning the modularity of the pain system have been focused on questions regarding the cognitive penetrability of pain mechanisms. It has been claimed that phenomena such as placebo analgesia demonstrate that the pain system is cognitively penetrated; therefore, it is not encapsulated from central cognition. However, important arguments have been formulated which aim to show that cognitive penetrability does not in fact entail a lack of modularity of the pain system. This paper offers an alternative way to reject the (...) modularity of the pain system, which is independent from, but consistent with, the presence of cognitive penetration. It is proposed that, given the current knowledge regarding the functioning and the structure of the pain system, there are good reasons to accept that certain central cognitive mechanisms are part of the pain system. It is argued that such a ‘cognitive constitution’ of the pain system entails that the pain system is not modular. (shrink)