Categorical Imperative
Kant's supreme principle of morality: act only on a maxim you can will as a universal law for all rational agents.
The categorical imperative is the central principle of Immanuel Kant's moral philosophy, articulated in the Groundwork of the Metaphysics of Morals (1785). Kant distinguishes hypothetical imperatives, which prescribe means to ends one happens to want, from the categorical imperative, which prescribes what reason itself requires of any rational will.
Kant offers several formulations: the universal law formulation (act only on that maxim through which you can at the same time will that it become a universal law); the formula of humanity (treat humanity, whether in your own person or in that of another, always as an end and never merely as a means); and the formula of autonomy (act as if you were a legislating member of a kingdom of ends). The three formulations are meant to express the same principle from different angles. The categorical imperative remains the canonical alternative to utilitarian and virtue-ethical accounts of moral action.