1. In some cases, departure from truth is prescribed by the moral sanction as a duty: such are all those in which mischief to another would be the certain or probable effect of verity, while from falsity no evil at all, or at least no equal evil, will, with equal probability, be the result: as, if a madman or assassin, with a naked weapon in his hand, asks whether his intended victim be not there, naming the place where he actually is.
2. To this same head may belong falsehoods of humanity or beneficence, as when a physician, to save pain of mind, gives hopes which he does not entertain himself.
3. To this same head may be referred what may be termed falsehoods of urbanity; which is but humanity or beneficence applying itself to interests of inferior moment: as where, on being interrogated by Artifex concerning the degree of estimation in which he holds a production of Artifex,—for fear of applying discouragement, Crito gives for answer a degree higher than that which he really entertains: and so in regard to conduct in life, taste, and so forth.
4. … where a man has no right to the information sought by him, the information need not be given to him.
(Jeremy Bentham, Rationale of Judicial Evidence, chapter 11)
