 The last great nineteenth century utilitarian moral philosopher, Henry Sidgwick, failed to find any constant felt feature in his experience of pleasure. He therefore proposed that “pleasure” picks out momentary experiences not by any specific introspected quality but rather by their intrinsic desirability, as may be cognitively apprehended at the time of experiencing (Sidgwick 1907, pp. 125–31, 111–5). He thus took the concept of pleasure to be irreducibly evaluative and normative, but still to apply to experience; experience is pleasant to the extent it wholly grounds reasons to desire, seek, or actualize it merely in how it feels. Mid-twentieth-century British and American philosophers departed still farther from the simple picture and associated empiricist traditions, influenced in part by behaviorism in psychology.