Post

Act only according to that maxim whereby you can at the same time will that it should become a universal law. This is the Categorical Imperative — not a rule but a test. When you consider an action, ask: what if everyone did this? If the universal adoption of the maxim would be self-defeating or contradictory, the action is impermissible. Lying is impermissible because a world in which everyone lies eliminates the very practice of truth-telling on which lying depends. The maxim refutes itself.