E.g. Principle of causality. These concepts and principles are justified only as conditions for the possibility of experience. They can legitimately be applied only to the objects of possible experience. Kantian ethics are grounded in reason. Not by religion.
Ethics are unconditional.
The Categorical Imperative. Duty accepts no terms. Kant believes that the principle of noncontradiction, on its own, can guide our actions. Consistency is the criterion of moral virtue. The essence of morality.