What must be the case in order to successfully lie to yourself? — Moliere

A lie needs a truth or unanswered question. If we consider the former then one can't possibly lie to oneself. If the latter then ignorance can always be replaced with a lie at random.

In fact I think the whole process of human thinking, the so-called hypothetico-deductive method, consists of entertaining possible explanations for a phenomenon and eliminating the lies to get to the truth. Looks like we do lie to ourselves but not for long IF we're rational.

People tend to stick to ego rather than logic or sense. Example: a woman learned, accidentally, of an ethnic tradition of her in–law-family to give relatives anything they like in her house. She's appauled that her in-law-relatives used this tradition to ask for her alarm clock and take it. She later on gives away to the strangers the only beautiful beeds she had out of spitefulness: let this not be her relatives, whom, she assumed, will asked for her beeds as well and she won't have them anyway. Her ego erased any logic or real sense. Building relationship with relatives did not take important place in her mind, but rather the need to be revengeful.

"Self-deception" is a description applied by someone else, yes? It's a judgement that you make about me (for example). But what if you are wrong? Should we question the judgement of 'self-deception'? Maybe so. After all, *I* don't think I'm deceiving myself; it's you who thinks that. Or are we considering how someone would purposefully deceive themselves? I assume not.

how someone would purposefully deceive themselves? I assume not. — Pattern-chaser

The latter is what I was considering. I'm not as interested, here, in determining how we might know others -- only the conditions under which one might lie to themselves. It could be that said conditions are not easily determinable due to practical considerations.