H. P. Grice, "Do not say what you believe to be false"

lying Ethics Deliberately saying what one knows or believes to be false in order to deceive one or more other persons. Liars have one thing in their mind and state another conflicting claim with the intention to deceive, or at least with a lack of care about the possibility of deceiving. There is disagreement whether there should be a universal moral prohibition against lying. Both Aquinas and Kant denounced lying as a moral vice. For Kant, truthfulness constitutes a basic moral relationship between rational beings. Because it violates this relationship, lying is wrong in itself, whether or not it produces good consequences. J. S. Mill, on the other hand, argued that lying to avoid a greater evil could be justified. This is also the position implied by Plato’s concept of the noble lie. According to the utilitarian principle that an act is morally permissible if it maximizes the good, lying is not simply an evil, but must be judged according to its good or bad consequences. Accordingly, the treatment of lying is an area in which the difference between deontology and utilitarianism is clearly indicated. “I shall define as a lie any intentionally deceptive message which is stated.” Bok, Lying