Gottlob August Tittel (1739–1816) was a professor at a Gymnasium in Karlsruhe and is best known as an early critic of Kant’s theoretical and practical philosophy. This chapter contains selections from his On Herr Kant’s Reform of Moral Science (1786), the first book-length commentary on the Groundwork. In this text, Tittel makes several important objections to the Groundwork, many of which have since become classic, such as: that the categorical imperative is empty, that the motive of duty for duty’s sake is impotent in human nature, and that Kant is a covert consequentialist. Tittel’s most famous objection, however, is that the categorical imperative is not a new principle of morality, but merely a new formula of a principle philosophers have known for a long time. Kant was aware of the Reform, and he responds to Tittel in a footnote in the Preface to the second Critique (see 5:8.28–37n).