His inability to focus his attention makes it hard for him to learn and master facts. He is ill informed about his own policies and tramples his own talking points. It makes it hard to control his mouth. On an impulse, he will promise a tax reform when his staff has done little of the actual work.

Second, most people of drinking age have achieved some accurate sense of themselves, some internal criteria to measure their own merits and demerits. But Trump seems to need perpetual outside approval to stabilize his sense of self, so he is perpetually desperate for approval, telling heroic fabulist tales about himself

“In a short period of time I understood everything there was to know about health care,” he told Time. “A lot of the people have said that, some people said it was the single best speech ever made in that chamber,” he told The Associated Press, referring to his joint session speech.