Why does Kant emphasize a "pure" moral philosophy derived from reason rather than experience? What does Kant mean by "duty"? What is the categorical imperative, and how does it relate to morality? What does Kant mean by the "kingdom of ends"?

Kant argues for the existence of a categorical imperative, a universal moral law that applies to all rational beings. He proposes that this imperative can be formulated as “Act only on that maxim whereby thou canst at the same time will that it should become a universal law,” meaning that our actions should be governed by principles that we could universalize without contradiction. Kant also explores the relationship between freedom and autonomy, asserting that freedom of the will is a necessary precondition for morality and that autonomy—the ability of reason to govern itself—is the foundation of moral action.