The motivated misapprehension of the facts of the case. This may include actively believing what is not true, and refusing to acknowledge a truth, in circumstances where without the motivation the truth would be obvious. The philosophical problem, sometimes called the paradox of self-deception, is that normal deception requires one agent who knows the truth, and who conceals it from another agent. So within a single agent the state appears to be impossible, since the agent must know the truth to begin a process of deceiving him or herself about it. One solution is to postulate one part of the mind that knows the truth, and that sets about deceiving another part of the mind that does not. However, it is not clear that it is useful to employ the spatial analogy of minds with parts, nor to suppose that the ‘sub-systems’ responsible for the state are usefully thought of as themselves independent ‘agents’ that not only know things but have plans and projects and can set about doing things. There is nothing problematic about desires influencing beliefs, and some people are better than others at believing what they wish to be true. The problem only arises if achieving this state is thought of as a plan that the agent follows. But even then the project of coming to believe what one knows to be false is coherent, provided that process is spread over time, and the means adopted involve losing the knowledge during the process. See also Pascal's wager.