The second section of "The Genealogy of Morals," called "'Guilt,' 'Bad Conscience,' and the Like," is another important document, the reading of which is almost imperative for the student who would understand the processes of thought which led to Nietzsche's philosophic conclusions. In this essay Nietzsche traces the origin of sin to debt, thereby disagreeing with all the genealogists of morals who preceded him. He starts with the birth of memory in man and with the corresponding will to forgetfulness, showing that out of these two mental qualities was born responsibility. Out of responsibility in turn grew the function of promising and the accepting of promises, which at once made possible between individuals the relationship of "debtor" and "creditor." As soon as this relationship was established, one man had rights over another. The creditor could exact payment from the debtor, either in the form of material equivalent or by inflicting an injury in which was contained the sensation of satisfaction. Thus the creditor had the right to punish in cases where actual repayment was impossible. And in this idea of punishment began not only class distinction but primitive law. Later, when the power to punish was transferred into the hands of the community, the law of contract came into existence. Here, says Nietzsche, we find the cradle of the whole moral world of the ideas of "guilt," "conscience," and "duty"; and adds, "Their commencement, like the commencement of all great things in the world, is thoroughly and continuously saturated in blood."