Groundwork of the Metaphysics of Morals
Groundwork of the Metaphysics of Morals (1785) by Immanuel Kant seeks the supreme principle of morality and locates it in reason itself: the categorical imperative.
Core Idea
Kant argues that moral worth comes from acting out of duty according to principles (maxims) one could will to be universal laws. The categorical imperative’s formulations — universalizability, and treating humanity always as an end and never merely as a means — make consistency the test of a moral rule.
Why It Matters for Critical Thinking
The universalizability test is a powerful consistency check: “What if everyone reasoned this way?” forces you to examine whether your values survive being applied without special exceptions for yourself.