What is a lie to a Darwinian materialist?
Vincit omnia veritas
Lying could be quite useful, genetically speaking, for a mafioso, while on trial, to save himself (and his family, cronies, business etc.). Say Guido ordered his boys to off some nosy-detective, and they do so, and then Guido lies about his guilt ("plead the fifth, paysano") when on trial (as of course many people accused of crimes do) and then goes to trial, but is acquitted, and in effect gets away with Moider, returns to his warehouse, and continues with his business, advances the gene pool a bit more via kids with Velma, etc. What does the strict Darwinian say? Guido succeeded, in a sense, by lying (a "don't get caught" meme, in contemporary parlance), and many criminals who lie about their guilt (at least ones with the right defense attorneys) do succeed; thus lying could in many instances be a positive trait. We here at Contingencies (and we do not advocate Catholics, Inc. as an alternative to DarwinCorp.) assume that most rational humans would object to Guido's lie, but those who hold to purely Darwinist or genetic determinism would appear to have no grounds for any such objections.
What is a lie to a pragmatist?
Pragmatists, idealists (at least some), mystics, and postmodernists generally assert that truth is not a matter of confirming some alleged facts, "out there", in an objective, empirical world. There are various differences between these groups, but it doesn't seem unreasonable to suggest that they uphold some version of William James concept of pragmatism: that truth always has some relation to usefulness, whether in regards to sciences, social sciences, humanities, etc.
The Cash Value of Truth model, has of course been criticized, and not without reason. While in some contexts--say medicine--utility would seem to be critical (--testing the functionality of a drug, say)--in others, whether history or law, or various social sciences, any modifications of the actual facts to fit some ideology might conceivably result in highly unethical situations. Bertrand Russell noted this problem in regards to Dewey's pragmatist ideas. If the pragmatist's goal is to create a harmonious community, or even harmonious classroom, or well-integrated self, then it would seem the pragmatist might "shape" facts (say historical, or economic facts, or even literary narratives) to fit his pedagogy--making the students see the world through rose-tinted glasses, more or less (or perhaps red-tinted glasses, in marxist indoctrination centers). And if the end result was a harmonious community and well-balanced individuals (or even a supremely efficient proletarian State), then pragmatists would grant, it would seem, that the right thing had been done. And other sorts of similar absurdities, possibly Orwellian, resulting from pragmatism (or any ideology where truth is solely a matter of functionality) across the board could be realized.