Abstract

IN THE GROUNDWORK OF THE METAPHYSICS OF MORALS Kant noted that, while the present work would be concerned only with the supreme principle of morality, he intended some day to write a "metaphysics of morals" in which he would set forth the whole system of man's duties derived from this principle. Twelve years later, in 1797, he published The Metaphysics of Morals in two parts: Metaphysical First Principles of the Doctrine of Right and Metaphysical First Principles of the Doctrine of Virtue. As the Groundwork made clear, the concept of duty contains that of constraint upon an agent who, because of impulses belonging to his sensible nature, does not necessarily do whatever is objectively necessary in accordance with moral laws. The first part of The Metaphysics of Morals is the system of moral principles on which are based laws prescribing duties that one can be coerced to fulfill. The second part is the system of duties for which only self-constraint through the thought of duty is possible. Each part is said to be a system of duties because it is derived from a first principle and remains on the level of principles that can be known a priori to be binding on men generally. Together they form the whole system of man's duties because the first principle of each is derived from the supreme principle of morality, the categorical imperative and the division in terms of coercion and self-constraint is exhaustive.