Interesting news from Science Daily:
"evidence that craving disrupts an individual's meta-awareness, the ability to periodically appraise one's own thoughts."A rationalist's foundation lies in his own thoughts ("I think, therefore I am"). If his mind is lying to him, he is lost - and he doesn't even know it.
Yet, evidence that his mind is lying to him (in certain circumstances) does nothing to shake his faith that it is not lying to him in other matters.
Perhaps, he is better called an Irrationalist.