is unclear whether all acts should be accepted if compensation is paid. Secondly, allowing anything if compensation is paid makes all people fearful. Nozick argues that if one knows that they will have their rights violated and then be compensated for it; they will still be fearful. This raises important problems: How will financial compensation make the assaulters pay not only for the damage but also for the fear that the assaulted had before that will not do, as the assaulter is not the only responsible of that fear. If that was the way to compensate, non-assaulted people would be left uncompensated for the fear they have. One cannot compensate anyone for fear after the fact because we remember the fear we had as less important than it actually was. Because of that, what should be calculated instead is what Nozick calls "Market Compensation", which is the compensation that would be agreed upon if the negotiations took place before the fact. But this is impossible, according to Nozick. The conclusion of these difficulties, particularly the last one, is that anything that produces general fear may be prohibited. Another reason to prohibit is that it would imply using people as a means, which violates the Kantian principle that he defended earlier. But if so, what about prohibiting all boundary crossing that isn't consented in advance? That would solve the fear problem, but it would be way too restrictive, since people may cross some boundaries by accident, unintentional acts, etc.) and the costs of getting that consent may be too high (for instance if the known victim is on a trip in the jungle). What then? "The most efficient policy forgoes the fewest net beneficial acts; it allows anyone to perform an unfeared action without prior agreement, provided the transaction costs of reaching a prior agreement are greater, even by a bit, than the costs of the posterior compensation process." Note that a particular action may not cause fear if it has a low probability of causing harm. But when all the risky activities are added up, the probability of being harmed may be high. This poses the problem that prohibiting all such activities (which may be very varied) is too restrictive. The obvious response, that is, establishing a threshold value V such that there is a violation of rights if (where p is the probability of harming and H is the