What are the motifs in Kant: A Very Short Introduction by Roger Scruton?

Duty as the foundation of ethics is a recurring idea in the book. Kant's ethical system is founded upon his transcendental philosophy. He believes that rational creatures are unique in the universe because of the fact that they are not subject to the same laws of necessity that governs all other things. This freedom or autonomy becomes the basis for his moral system; a person has moral value as a result of their autonomy. Therefore, the essence of the moral law derives from the assumption that to be ethical means to be autonomous.