There is a long tradition of riddles and paradoxes that revolve around a blatantly bogus dichotomy between people whose every statement is true and those whose every statement is false. There is no middle ground. While I do enjoy these little mind-games, they paint a very unrealistic picture which, sad to say, has the unfortunate side-effect that folk who should know better fail to make sense of real-world behaviour because they're too busy shoe-horning them into a model based on this utterly unrealistic paradigm.
In the formal system of truth-tellers and those whose every utterance is perfectly false, the former are called honest and the latter liars. Herein lies the problem: in the real world, neither honesty nor lying works the way the myth pretends. The first and simplest difference is that there are, in reality, folk who do their best to be honest in many contexts but, in others, engage in various forms of obfuscation up to and including outright lying. In fact, that's most of us most of the time.
Perhaps most important is the misrepresentation of what it means to lie. In
the mythical world, a liar
conscientiously always says things that are
exactly opposite to truth. This, in fact, could be considered a form of
honesty, if anyone actually practiced it: anyone who had had enough dealings
with such a person as to discern that this was their game would, in practice,
receive from them a fully honest account of the world. Just negate what they
say, and away you go. That is not what liars do, in the real world.
The whole point of lying is to decieve. I turns out that, to deceive folk, saying quite a lot of true things mixed up with the untruths makes it much more likely that they'll mistake the latter for truth: so liars routinely say things that are true, in order to lull those they wish to deceive into falling for their lies. But that doesn't even get close to the full spectrum of ways that folk can deceive: it's entirely possible to say things that are all entirely factually true but – by careful juxtaposition of carefully-chosen truths and framing of the narrative around them – make it easy to lead folk astray by seemingly reasonable inference from those things (without mention of, typically, a whole spectrum of facts that would complicate the matter).
Furthermore, even the honest are not so simple as to simply give (without further qualification) a true answer to a question: if they believe the questioner is in danger of being mislead by their misguided question, they will try to provide the context that will undeceive them. And, of course, even the honest can be honestly wrong, or fail to anticipate a way you might misunderstand an honest answer.
Let's take a famous example. As you approach a fork in the road, at which
you can see there is a house, you read a sign warning you that one of the
inhabitants always tells the truth but the other is always scrupulously careful
to tell you something untrue. You need to know which side of the fork to reach
your destination – let's call it Thebes – and the correct
solution is to ask one of the two residents If I asked your companion which
fork in the road would most directly bring me to Thebes, what answer would I get
?
If you asked the systematic speaker of exact falsehoods, he would
tell you the wrong road, because that is the opposite of what he knows his
truth-telling companion would have told you. If you ask the truth-teller, his
answer shall be the same, because that's the lie his companion would have told
you. So you take the opposite fork to whatever answer you get.
A marginally more realistic model of the range of honesty and deception, however, tells a different story. At one extreme, let's call him Francis, we have someone (highly intelligent and well-informed) committed to doing well by those he encounters; he'll tell you the truth when he's confident that won't deceive you, and expand on the reality of the situation around your question otherwise. At the other, let's call him Loki, we have someone (equally intelligent and well-informed) who delights in deceiveing, but understands fully well how to deceive by supplying true answers – and, especially, by reframing the problem into some form that admits an answer you'll believe that shall, none the less, deceive you. If the sign on the road really means this peculiar couple inhabit the house on the junction, you may be in trouble. If you ask Francis your carefully-prepared question, he'll recognise you for the idiot you are and, if compassionate, explain how misguided your reasoning is. He probably won't tell you which branch of the fork to take; I'll explain why in due course. I'm not entirely sure what Loki would tell you if you simply ask him, while Francis watches, because Loki is cleverer than I can emulate.
However, if you put a sword to Francis's throat and command silence of him, while asking Loki, there's a decent chance Loki shall tell you the actual path to Thebes, confident that you're so stupid you'll take the other path – thereby deceiving you with the truth, because he's read the sign you read on the road in, and enjoyed solving and subverting the riddle. Meanwhile, if you put a sword to Loki's neck and demand an answer of Francis, I suspect Francis shall (possibly via a lecture on compassion for your fellow folk) explain to you that you have fallen, like the local coucnil that put up the sign that has mislead you, for a misundestanding of what truth and honesty are. Francis – in this scenario – might also take issue with your unkindness to the compulsive deceiver with whom he lives, and probably won't make any attempt to answer your original question because, frankly, if he would have done so, Loki (were their situations reversed, and Loki not in the mood for the easy way out sketched above) could have faked all of the preceding and then deceived you. Which is why I can only say, of the other way round, that there is a decent chance Loki would deceive you by telling the truth: it might amuse him more to pretend to be Francis, responding as just given, and (without saying it out loud) slipping in hints that might lead you to interpolate which fork in the path leads to Thebes. Those hints might actually point the right way (if Loki was confident you'd believe you'd spotted him playing this double-bluff) or opposite (otherwise) and you'd be an idiot to trust your guesses about Loki.
Now, this model of honesty and deceoption is still not truly realistic, but I trust you can see, from it, how very far from reality the traditional formalism is. My Loki here will deceive you just for the mischievous fun of doing so, without regard to whether he gains by the deception. Herein lies the difference between him and the real world's most pernicious liars.
Aside from the subtleties of how a sincere intent to deceive or faithfully
inform can play out, there is at least one other pattern of behaviour that can
confuse and complicate the story. There are folk who do not even care to think
about whether what they are saying is true or false, or about whether what they
say shall deceive of faithfully inform you. Some folk concern themselves only
with how folk shall respond to what they say, and with saying the things that
shall get the responses they want from folk. The question of whether what they
say is true or not simply doesn't arise for these people: it may be true, or
false, or utterly meaningless for all they care, so long as it elicts the
response they want. Calling such manipulators liars
– at least in
the sense of the tradition above – misses the point: the liar knows which
parts of what he says are true and which false, designing his selection of the
former to trick you into mistaking the latter for more of the same. The
manipulator, on the other hand, neither knows nor cares about the truth or
otherwise of their utterances.
This characterisation of the manipulator is, indeed, a more faithful description of real-world liars. The vernacular surely calls the manipulator a liar and cares not at all about whether the liar knew their lies were falsehoods, or intended to deceive: the vernacular's real concern is with the opposite of honesty that the manipulator is engaged in even when making true statements. Honesty demands not so much that our statements be true as that we respect those to whom we make them as beings with an understanding of the world that they shall revise in light of what we say; as a result, what we say may enrich or pollute their understanding of the world, which guides and shapes their actions and lives. Polluting that understanding therefore harms them, by potentially causing them to make bad decisions or take actions contrary to their intent, values or interests; enriching it empowers them to better deal with the world. Honesty, seen in this light, is thus about helping them to improve their understanding of the world; in contrast, the manipulator seeks to elicit from them a response that serves the manipulators purpose; in so doing, with reckless disregard for the harm it may do to those manipulated, they show contempt for their fellow's understanding of the world.
The true nature of honesty and lying, then, lies not in the accuracy or inaccuracy of the statements we make (for all that honesty does strive for accuracy, and liars do not) so much as in the respect we show for those whose understanding we influence by what (and how) we communicate. The honest may hope to persuade you to some course of action, but they respect your right to informed consent, to be the true author of your actions, where the manipulator only cares about the aligning your actions with their goals, treating you as a puppet rather than a free agent.
Written by Eddy.