We have all heard Donald Trump at various times proclaim what a genius he is and how he knows so much more about practically everything than anyone else. Thanks to Rod Painter, I came across this tweet that has a mashup of all the times he has made this kind of boast. To see them consecutively is really something.

Trump is the #1 expert on…
– Taxes
– Construction
– Campaign finance
– Drones
– Technology
– U.S. History
– Infrastructure
– ISIS
– Facebook
– Renewables
– Polls
– Courts
– Steel workers
– Golf
– Banks
– Nuclear arms
– The system
– Debt
– Politicians

…according to Donald Trump pic.twitter.com/Pfh92Gtmtc

— NowThis (@nowthisnews) January 4, 2019

As James Fallows writes, there are certain common characteristics shared by people who are really knowledgeable and expert in certain areas.

Here are three traits I would report from a long trail of meeting and interviewing people who by any reckoning are very intelligent.

• They all know it…
• Virtually none of them (need to) say it…
• They know what they don’t know. This to me is the most consistent marker of real intelligence. The more acute someone’s ability to perceive and assess, the more likely that person is to recognize his or her limits. These include the unevenness of any one person’s talents; the specific areas of weakness—social awkwardness, musical tin ear, being stronger with numbers than with words, or vice versa; and the incomparable vastness of what any individual person can never know…

  But generally the cliche is true: The clearest mark of intelligence, even “genius,” is awareness of one’s limits and ignorance.

* * *

On the other hand, we have something known as the Dunning-Kruger effect: The more limited someone is in reality, the more talented the person imagines himself to be. Or, as David Dunning and Justin Kruger put it in the title of their original scientific-journal article, “Unskilled and Unaware of It: How Difficulties in Recognizing One’s Own Incompetence Lead to Inflated Self-Assessments.”

Odds are that the world’s most flamboyant illustration of this dangerous misperception, despite his claimed omniscience, would not even recognize the term, nor its ominous implications in his case.

Every time Trump opens his mouth, we see the Dunning-Kruger effect in action.