Full Idea
Kant was a psychological hedonist about all actions except those done for the sake of the moral law, and this faulty theory of human nature prevented him from seeing that moral virtue might be compatible with the rejection of the categorical imperative.
Gist of Idea
Kant thought human nature was pure hedonism, so virtue is only possible via the categorical imperative
Source
comment on Immanuel Kant (Groundwork of the Metaphysic of Morals [1785]) by Philippa Foot - Morality as system of hypothetical imperatives p.165
Book Reference
Foot,Philippa: 'Virtues and Vices' [Blackwell 1981], p.165
A Reaction
Nice. Kant wasn't unusual in his view, which seems standard in the Renaissance and Enlightenment. Aristotle understood that it is human nature, on the whole, to want to be a good citizen, since we are social beings.
Related Idea
Idea 22389 Morality no more consists of categorical imperatives than etiquette does [Foot]