Wikipedia said:Hare posited two extreme cases of people, one of whom would only use critical moral thinking and the other of whom would only use intuitive moral thinking. The former he called the 'archangel' and the latter the 'prole'. ... according to his theory each person shares the traits of both to limited and varying extents at different times. The archangel has superhuman powers of thought, superhuman knowledge and no weaknesses. This unbiased 'ideal observer', when presented with an unfamiliar situation, would be able to immediately scan all potential consequences of all possible actions in order to frame a universal principle from which he could decide an appropriate action for the situation. Such a person would not need a set of intuitive moral rules, as he would be able to decide the correct response to any possible situation by reason alone. By contrast, the prole has these human weaknesses to an extreme degree. He must rely upon intuitions and sound prima facie principles all of the time, as he is incapable of critical thought. The set of intuitive moral rules that the prole follows must be simple and general enough that they can be easily understood and memorised, and also quick and easy to use. Once one has identified the different types of moral thinking, the next step is to identify when one ought to think like an archangel, and when like a prole. Hare identifies three types of situation where critical thinking is necessary. The first is when the intuitive general principles conflict in particular cases. The second is when, "though there is no conflict between principles, there is something highly unusual about the case which prompts the question whether the general principles are really fitted to deal with it."[9] Thirdly, and most importantly, critical thinking is necessary in order to select the intuitive prima facie principles that will be used.