The colourful name that Keynes gave to one of the essential ingredients of economic prosperity: confidence. According to Keynes, animal spirits are a particular sort of confidence, "naive optimism". He meant this in the sense that, for entrepreneurs in particular, "the thought of ultimate loss which often overtakes pioneers, as experience undoubtedly tells us and them, is put aside as a healthy man puts aside the expectation of death". Where these animal spirits come from is something of a mystery. Certainly, attempts by politicians and others to talk up confidence by making optimistic noises about economic prospects have rarely done much good.