In "Grounding for the Metaphysics of Morals", Immanuel Kant develops his thesis that claims morality can be derived from the principle of the categorical imperative. The strongest argument to support his thesis is the difference between actions in accordance with duty, and actions in accordance from duty. To setup his thesis, Kant first draws a distinction between empirical and "a priori" concepts. Empirical concepts are ideas we reach from our experiences in the world. In contrast, "a priori" concepts are ideas we reach prior to, or apart from any experience of how things occur in the world. Kant claims that moral actions must be based on "a priori" concepts of reason, and that they are universally valid, only if they are based on "a priori" concepts. He develops a philosophical system based exclusively on reason. "Reason's function is to bring a will that is good in itself, as opposed to good for some particular purpose."(SparkNotes.com)
             Kant presents three propositions about duty. First, is the will that is a morally good action if it is done in accordance from duty. Second, is that actions are judged by the "maxim" or principle that was the motivation behind the action. Third, explains that is not the respect for the law, but rather it is the moral motivation of an individual who recognizes that the law is an imperative of reason that goes beyond our other interests. The will is of practical reason. One acts by the conceptions of laws. The discipline of action is a will. Our action based on our judgment is defined an imperative or a command to act on a certain motive.
             An imperative can be either hypothetical or categorical. In the hypothetical imperative one acts in a certain way if one will obtain or achieve a certain goal, based on a previous circumstance. Thus, this type of action cannot be universally valid at all times. The categorical imperati...