The most interesting criticism of Christopher Hill's The World Turned Upside Down may be Barry Reay's observation that it never really resolves “the wider issue of rationality.” As Reay points out, Hill wavers between a respect for seventeenth-century radical enthusiasts as seen in their own terms and an occasional tendency to see them as blinkered by their pre-scientific, pre-secular perspective. The question of individual irrationality, moreover, is handled in a tone of quizzical ambiguity. Hill offers a number of tentative explanations for the extent to which such enthusiasts play the role of holy madman, including the following: such enthusiasts are engrossing the attention of an unwilling audience; they are using a mask to simultaneously express and disown dangerous ideas; they are reflecting the sheer strain of their radical insights; and they are, in some cases – Thomas Tany and George Foster, perhaps – suffering an authentic mental breakdown. Though he drops hints that drawing a line between the rational and the mad may involve political and historical considerations, Hill leaves such hints studiously undeveloped.