If a person communicates that they believe the world works in one fashion, when in reality, it works in another, three situations are possible. Perhaps more than three, but certainly at least these three.
The first is that they are mistaken. If a person is mistaken about reality, you would expect their actions of consequence to resemble those they would take if they truly believed in their mistake. Similarly, were you to torture them, screaming at them "tell me about how the world works!" they would never answer you that the world works in a way different than their misconception.
The second is that they are lying with confidence. If a person is lying with confidence, you would expect their actions of consequence to resemble those they would take if they did not truly believe in their lie. Were you to torture them in the same manner as the example in the previous paragraph, they would eventually, under sufficient pressure, answer you that the world works in a way different than their lie, i.e., truthfully.
The third is that they are lying without confidence. If a person is lying without confidence, you would expect their actions of consequence to resemble those they would take if they did not truly believe in their lie, same as if they were lying with confidence. However, were you to torture them in the UE-approved manner, they would never answer you in a way that contradicts their lie.
How is this possible? Lying without confidence is where a lie is generated, and then is never spoken aloud, never recognized as a lie, and thus the liar has no internal memory space dedicated to remembering that it is a lie. In the first generation, this might be called lying to yourself or burying the truth, but it has become commonplace since the 17th century or so to pass these lies down from generation to generation, like antique furniture. Thus, these terms are insufficient to describe the phenomenon in the second generation or later. A liar of this variety cannot possibly answer you with the truth, because in order to do that he must have been the architect of the lie, and granddad never passed down the blueprints. Such a lie exists via the magic of ritual. A liar-without-confidence repeats his lie as a social ritual, one which has no bearing on how his decisions of consequence are made. Decisions of no consequence, of course, are free to be used as simple decor, and may, in fact be used to support the lie.
Just don't ask him to move to a black neighborhood.