Some habitual liars are called “pathological” liars because they lie for no apparent reason. They lie even at times when the truth would suffice or serve them better. Some have regarded such senseless lying as a kind of mental illness or even insanity. But these liars are not insane. Rather, they belong to a group of the most severely disordered characters among us (i.e. psychopaths, sociopaths, etc.), and they’re perfectly rational. There’s a “method” to their apparent “madness.”