accept that some individuals may harm some innocent in certain cases? (This non-aggression principle does not include, of course, self-defense and perhaps some other special cases he points out.) He then goes on to expose some problems with utilitarianism by discussing whether animals should be taken into account in the utilitarian calculation of happiness, if that depends on the kind of animal, if killing them painlessly would be acceptable, and so on. He believes that utilitarianism is not appropriate even with animals. But Nozick's most famous argument for the side-constraint view against classical utilitarianism and the idea that only felt experience matters is his Experience Machine thought experiment. It induces whatever illusory experience one might wish, but it prevents the subject from doing anything or making contact with anything. There is only pre-programmed neural stimulation sufficient for the illusion. Nozick pumps the intuition that each of us has a reason to avoid plugging into the Experience Machine forever. This is not to say that "plugging in" might not be the best all-things-considered choice for some who are terminally ill and in great pain. The point of the thought experiment is to articulate a weighty reason not to plug in, a reason that should not be there if all that matters is felt experience. Prohibition, compensation, and risk The procedure that leads to a night-watchman state involves compensation to non-members who are prevented from enforcing their rights, an enforcement mechanism that it deems risky by comparison with its own. Compensation addresses any disadvantages non-members suffer as a result of being unable to enforce their rights. Assuming that non-members take reasonable precautions and adjusting activities to the association's prohibition of their enforcing their own rights, the association is required to raise the non-member above his actual position by an amount equal to the difference between his position on an indifference curve he would occupy were it not for the prohibition, and his original position. The purpose of this comparatively dense chapter is to deduce what Nozick calls the Compensation Principle. That idea is going to be key for the next chapter, where he shows how (without any violation of rights) an ultraminimal state (one that has a monopoly of enforcement of rights) can become a minimal state (which also provides protection to all individuals). Since this would involve some people paying for the protection of others, or some people being forced to