The previous chapters showed that Spinoza justifies ethical prescriptions, including the natural law, on the grounds that they are good. Since the good amounts to what promotes one's power, it follows that Spinoza is committed to ethical egoism, the view that the right action best promotes our self-interest. Spinoza openly embraces this view, arguing that advantage determines even the permissibility of acts: “whatever we deem good, that is, advantageous for preserving our being and for enjoying a rational life, it is permissible for us to take for our use and to use it as we please” (4app8). While one might regard this commitment as tantamount to a rejection of conventional morality, ethical egoism can consistently defend the value of benevolence on self-interested grounds. Spinoza clearly meant to take this tack, since he holds that there is a natural law requiring us to act for the good of others. Spinoza's justification for this claim is that our good consists in following reason's guidance, which directs us to the good of others: “he who lives by the guidance of reason endeavors as far as he can to repay with love or nobility another's hatred, anger, contempt towards himself” (4p46). This chapter aims to explain why, according to Spinoza, reason directs us to act with benevolence, in other words, the basis for what I have called the second natural law.