Supererogation (Late Latin: supererogatio "payment beyond what is needed or asked", from super "beyond" and erogare "to pay out, expend", itself from ex "out" and rogare "to ask") is the performance of more than is asked for; the action of doing more than duty requires. In ethics, an act is supererogatory if it is good but not morally required to be done. It refers to an act that is more than is necessary, when another course of action—involving less—would still be an acceptable action. It differs from a duty, which is an act wrong not to do, and from acts morally neutral. Supererogation may be considered as performing above and beyond a normative course of duty to further benefits and functionality. Some philosophers have proposed a corresponding concept of suberogation – whereas supererogatory acts are praiseworthy but not morally required, suberogatory acts are morally discouraged but not prohibited. However, the concept is controversial; with some dispute as to whether suberogatory acts genuinely exist. In the theology of the Roman Catholic Church, "works of supererogation" (also called "acts of supererogation") are those performed beyond what God requires. The Roman Catholic Church holds that the counsels of perfection are supererogatory acts, which specific Christians may engage in above their moral duties. Similarly, it teaches that to determine how to act, one must engage in reasonable efforts to be sure of what the right actions are; after the reasonable action, the person is in a state of invincible ignorance and guiltless of wrongdoing, but to undertake more than reasonable actions to overcome ignorance is supererogatory, and praiseworthy. According to the classic teaching on indulgences, the works of supererogation performed by all the saints form a treasure with God, the "treasury of merit," which the church can apply to exempt repentant sinners from the works of penitence that would otherwise be required of them to achieve full remission of the temporal punishment due to their sin.