Immanuel Kant's work on morality and ethics primarily comes from his "Grounding for the Metaphysics of Morals," which describes the history of the way in which people have traditionally thought about morality and Kant's amendments to the prevailing theories of his time. In "Grounding for the Metaphysics of Morals," Kant argues against empirical reasoning for morality and approaches moral questions a priori, or dealing with concepts instead of observing human beings and behavior. In the course of his work, he sets up three basic principles that define morality.

Defense of A Priori Approach

Although Kant's defense of using an a priori approach is not explicitly one of his moral principles, it underlies all of his analyses and conclusions. He approaches ethics and morality without using empirical data but instead dealing with concepts, because all concepts of morality deal with certain values, such as "duty," "justice," "good will," and "obligation." Serious consideration of moral issues, for Kant, must first deal with the ways in which these concepts are understood. Thus, he approaches moral questions a priori, from the perspective of the concepts.

Universal Law

The first of Kant's principles of morality may be called the universal law or maxim. Kant claims that the basic principle of morality should be that individuals should act in such a way that they could want their maxim (motivation for acting) to be universal. This led Kant to describe such a universal maxim as a "categorical imperative." This simply means that all individuals should act in such a way that they would wish all others to follow the same guiding principle.

Treat Humans as Ends

The second of Kant's principles claims that a person should never treat another person as a means to an end. He separates individuals and objects into two categories: means and ends. Humans, he claims, should always be thought of as ends, or autonomous individuals with their own goals and desires. Treating others as ends promotes equality, because each person recognizes the other as an individual.

Everyone is a Rational Agent

Because all of Kant's moral conclusions came from reasoning and a priori conclusions, he felt that all rational beings ought to be able to come to the same moral conclusions that he did. Therefore, his third moral principle is that his moral conclusions are universally available to all rational agents, who can use mental faculties to come to the same principles. Kant argued that all humans should be thought of in this way, as capable of arriving at moral conclusions through the process of reasoning.