Fundamental Principles of the Metaphysic of Morals

The Fundamental Principles of the Metaphysic of Morals (Grundlegung zur Metaphysik der Sitten) is a work by Immanuel Kant on the development of a basis for what is morally permissible and what is morally obligatory. The title is sometimes translated into English as Grounding for the Metaphysics of Morals or Groundwork for the Metaphysics of Morals.

To this end, Kant devised the notion of a maxim, an internal rule for what action to take given a set of circumstances. Morally permissible behavior is then determined by the universalisation of that maxim - what if everyone were to behave the same way, given these circumstances, according to this maxim? If everyone could act this way without bringing an end to civilized culture, the behavior is morally permissible. If the inverse - what if no one behaved this way? - does bring about the destruction of civilization, then the behavior is morally obligatory.

This devised test is called the Categorical Imperative and is the centerpiece of this work. If one accepts that a purpose to destroy civilization is in itself contrary to moral behavior, then this work is in essence a logical proof of the Golden Rule.

Kant further expanded these ideas in a later work, the Metaphysics of Morals.