Stefano Bacin

Both in historical debates and in recent discussions, the Guise of the Good Thesis represents a genuine dogma of rationalism in moral philosophy. Many influential commentators have maintained that Kant belongs in that camp, even that he “explicitly endorses” the Thesis. Attributing the Thesis to Kant, however, faces scarce textual support and amounts to a dubious understanding of the relationship of Kant’s moral philosophy to previous rationalist views. I suggest that, in Kant’s view, the Thesis only applies to the determination of the will through the moral law. The principle that prior rationalists regarded as descriptive acquires in Kant’s terms a normative status.

The contrast between Kant’s moral philosophy and Feder’s is not less crucial than the controversy caused by the Göttingen review of the first Critique. One of main targets of Kant’s moral philosophy was Feder’s view, which can be regarded as Kant's main competitor in the contemporary debate. I thus argue that the background provided by the conflict with Feder shows significant distinctive traits of Kant's view, with regard to three fundamental issues. First, I examine how the project of a pure moral philosophy opposes Feder’s empirical investigation into the will, which is in fact one of the targets of Kant's criticism against universal practical philosophy. Second, a central element of Kant’s anti-eudaemonism, the contrast between happiness and self-contentment, is a rejection of the strongly moralized view of happiness that underlies Feder’s eudaemonism. Finally, I examine Tittel's objection that Kant had provided "only a new formula" of morality and Kant's response, which display a fundamental contrast between Kant’s understanding of the aims of moral theory with Feder’s common-sense conception.