 The challenge for (i) is to account for the difference in kind between the irrationality of common beliefs that are ungrounded and resistant to change (such as superstitious beliefs or beliefs in alien abduction) and the irrationality of delusions. There is abundance of evidence that delusional phenomena are widespread in the normal population, which suggests that a sharp dichotomy between the normal and the pathological would be at best a simplification (see Maher 1974, Johns and van Os 2001, Bentall 2003, 2018, and Sullivan-Bissett 2020).