That's more complicated. Often our beliefs aren't even coherent. (The canonical example is the "I have a Dragon in my garage", where any experiment you can come up with will fail to show the presence of my Dragon, and I know it, even though I still "believe" there is a Dragon.)
So it is possible to lie to yourself. Rationalization, wishful thinking, motivated cognition… As we are on average terrible liars, it's often easier to first convince ourselves of the lie, then repeat it with a straight face.
I have never met a person that never lies. But they rarely consider it "lying". It is a thresh-hold issue, a matter of getting through life and a balance between morality, convenience, and what level of inaccuracy constitutes falsehood.
"I put that I delivered them tomorrow, because it keeps the books simpler, but can you just sign today? Okay, thanks man!"
I've posted this before, but it's worth posting it again:
None of us could live with an habitual truth-teller; but thank goodness none of us has to. An habitual truth-teller is simply an impossible creature; he does not exist; he never has existed. Of course there are people who think they never lie, but it is not so—and this ignorance is one of the very things that shame our so-called civilization. Everybody lies—every day; every hour; awake; asleep; in his dreams; in his joy; in his mourning; if he keeps his tongue still, his hands, his feet, his eyes, his attitude, will convey deception—and purposely. Even in sermons—but that is a platitude.
The problem is that lying on a resume is very closely related to a situation that will arise in most development jobs and which can really damage a team. Consider a developer who is in a status meeting and is behind or having trouble with their current project. Someone who lies on their resume is much more likely to be one of those people who try to cover it up, lie about the current status, or shift blame. It means that the project lead is always going to be second guessing their status reports and unsure whether to really trust their estimates.
I hear this stuff all the time, "yeah, it is almost done, I just didn't get it checked in...". Probably code for having major problems or sometimes not even having started it. If you get in a work environment with many of these characters, life sucks.
We can't see into the minds of others, and what I've observed is that many of the people who lie, do not even seem to realize they are lying. They don't accept themselves as liars. They twist their view of reality to the point where the self serving lies are truth. I've seen this reality change almost instantaneously when the needs of the lie shifted.
Think about politicians. Do politicians know they're lying when they lie? I think in some cases this is the case, but I think in many cases they have convinced themselves of the lie for so long that they can't even conceive that it isn't the truth. Probably goes a long way towards making them convincing to others.
