Full Idea
Affability, sociability, courtesy, hospitality and gentleness in argument ...are merely the manners one is obliged to show in social intercourse, ...and so they promote a virtuous disposition by at least making virtue fashionable.
Gist of Idea
We are obliged to show the social virtues, but at least they make a virtuous disposition fashionable
Source
Immanuel Kant (Metaphysics of Morals II:Doctrine of Virtue [1797], 473-4 I.II App)
Book Reference
Kant,Immanuel: 'The Metaphysics of Morals', ed/tr. Gregor,Mary [CUP 1991], p.265
A Reaction
His emphasis on rational duty forces him to diminish virtue, making it sound hypocritical. He needs Aristotle's distinction between the controlled [enkratic] man and the man of true virtue (which is rational and whole-hearted).