The moral philosophy of Immanuel Kant is based upon notions of ôprincipleö, ôdutyö and ôreasonö; in his Fundamental Principles of the Metaphysics of Morals, he presents these ideas, seeking to devise a framework upon which all moral obligations may be grounded.
By ôreasonö, Kant suggests that in humans, actions must be guided by something other than instinct. As intelligent beings, humans are endowed with reason as ôa practical faculty, i.e. as one which is to have influence on the willö (20). The purpose of reasonùindeed, the culmination of itùis to produce a will in the individual that is good. As Kant explains, individuals should use reason ôto produce a will, not merely good as a means to something else, but good in itself, for which reason was absolutely necessaryö (21). In this, Kant is showing that reason has a practical destination: the establishment of a good will. In the human condition, a good will is manifested wherever one acts for the sake of ôdutyö. Reason helps us to understand just what our duties are.
Kant explains that actions done from duty create moral value or, in other words, that an action can only have moral worth if it is performed from a sense of duty (24). This idea constitutes the crux of KantÆs first proposition. KantÆs second proposition explains that ôan action done from duty derives its moral worth, not from the purpose which is to be attained by it, but from the maxim by which it was determinedö (24). On this view, an action should not rely upon a presumed outcome in order to acquire moral value; on the contrary, the principle guiding the action is an end unto itself; this Kant calls the ôprinciple of volition by which the action has taken place, without regard to any object of desireö (24). Lastly, Kant asserts that duty, ultimately, ôis the necessity of acting from respect for the lawö (25). Essentially, we must follow practical law, or objective prin...