Passage A

Saint Augustine wrote that to proceed against lies by lying would be like countering robbery with robbery. To respond to wrongdoing by emulating it is certainly at times to accept lower standards.

And yet it has seemed to many that there is indeed some justification for repaying lies with lies. Such views go back as far as the kind of justice that demands an eye for an eye. They appeal to our sense of fairness: to lie to liars is to give them what they deserve, to restore an equilibrium they themselves have upset. Just as bullies forfeit the right not to be interfered with by others, so liars forfeit the right to be dealt with honestly.

Two separate moral questions are involved in this debate. The first asks whether a liar has the same claim to be told the truth as an honest person. The second asks whether one is more justified in lying to a liar than to others.

In order to see this distinction clearly, consider a person known by all to be a pathological liar but quite harmless. Surely, as the idea of forfeiture suggests, the liar would have no cause for complaint if lied to. But his tall tales would not constitute sufficient reason to lie to him. For the harm to self, others, and general trust that can come from the practice of lying has to be taken into account in weighing how to deal with him, not merely his personal characteristics.

Passage B

A view derived from Immanuel Kant holds that when rational beings act immorally toward others, then, by virtue of their status as rational beings, they implicitly authorize similar actions as punishment aimed toward themselves. That is, acting rationally, one always acts as one would have others act toward oneself. Consequently, to act toward a person as that person has acted toward others is to treat that person as a rational being, that is, as if that person's act is the product of a rational decision.

From this it might be concluded that we have a duty to do to offenders what they have done, since this amounts to according them the respect due rational beings. But the assertion of a duty to punish seems excessive, since if this duty to others is necessary to accord them the respect due rational beings, then we would have a duty to do to all rational persons everything—good, bad, or indifferent—that they do to others. The point is rather that by your acts and by virtue of your status as a rational being, you authorize others to do the same to you; you do not compel them to do so. The Kantian argument leads to a right rather than a duty. Rational beings cannot validly object to being treated in the way in which they treated others. Where there is no valid complaint, there is no injustice, and where there is no injustice, others have acted within their rights.