Kant purposes to lay bare the fundamental principle of morality and show that it applies to us. Central to the work is the role of what Kant refers to as the "categorical imperative", the concept that one must act only according to that precept which he or she would will to become a universal law. He provides a groundbreaking argument that the rightness of an action is determined by the principle that a person chooses to act upon. This stands in stark contrast to the moral sense theories and teleological moral theories that dominated moral philosophy at the time of Kant's career.