Never to Lie

If there is one standpoint which unites contemporary moral philosophers of every persuasion it is a rejection of Kant's unequivocal precept "Thou shalt not lie" in the Preface to the Groundwork of the Metaphysics of Morals, the work which marks the beginning of his mature ethical philosophy. Here and elsewhere Kant defines a lie as an intentionally untruthful declaration and argues that utterances of this kind are shown by the categorical imperative to be immoral because a maxim of lying cannot also be willed as a universal law valid for all human beings. The standard objection to an unrestricted prohibition of lying is, of course, that it leaves a person defenceless in the face of wrong-doing and renders them as Korsgaard (1986) puts it, a "tool of evil". Damning indictments of this kind have been repeated endlessly since the publication of the Groundwork in 1785 and continue in recent commentaries even by those who in other respects find some value in Kant's Critical Philosophy. In Kant. A Revolution in Thinking (2025), for example, Willaschek maintains that Kant misapplies the categorical imperative and this leads him to the mistaken belief that lying in all circumstances and for any reason is immoral. So Willaschek proclaims: "To put a friend to the sword just in order to save oneself from having to lie is not a moral imperative but despicable and cowardly." And in a similar fashion Timmermann maintains in Kant and the Supposed Right to Lie (2025): "The fact remains that Kant did declare truthfulness to be more important than the life of a friend, both from the standpoint of formal juridical duty and from the point of view of ethics; and anyone interested in his moral philosophy would do well to take this position seriously."