Lie - Wikipedia, the free encyclopedia
1. Lying is a perversion of the natural faculty of speech, the natural end of which is to communicate the thoughts of the speaker.
2. When one lies, one undermines trust in society.
The most potent words that Kant ever spoke were on the subject of lying an are embodied at item 2 above.
What Kant means by this is that they way that we judge an action to be moral is to universalise it: If I want to know if telling a lie on a particular occasion is justifiable, I must try to imagine what would happen if everyone was to lie. Kant thinks that any rational being would agree that a world in which there is no lying is preferable to one in which lying was common; in a society in which lying was common no one could trust the word of anyone else.