In this chapter I offer an account of the nature, scope, and significance of Wolff’s claim that human beings have a duty to cognize moral good and evil. I illustrate that Wolff conceives of this duty as requiring that human beings both acquire distinct cognition of good and evil as well as avoid ignorance and error. Although Wolff intends for the duty to be quite demanding, he restricts its scope by, among other things, claiming it primarily concerns those who have (...) the skills, circumstances, and opportunity to acquire such cognition. Wolff calls these individuals the ‘inventors’ of the truths of morality and he considers himself to be such an inventor. I argue that part of the significance of this duty lies in the fact that Wolff conceives of himself as living up to it by writing the German Ethics, thereby sharing the knowledge he has ‘invented’ with others. (shrink)