The most striking claim of the book is that there is a very close parallel between prudential reasoning in one's own interests and moral reasons to act to further the interests of another person. When one reasons prudentially, for example about the future reasons that one will have, one allows the reason in the future to justify one's current action without reference to the strength of one's current desires. If a hurricane were to destroy someone's car next year at that point he will want his insurance company to pay him to replace it: that future reason gives him a reason, now, to take out insurance. The strength of the reason ought not to be hostage to the strength of one's current desires. The denial of this view of prudence, Nagel argues, means that one does not really believe that one is one and the same person through time. One is dissolving oneself into distinct person-stages.