Mr. Trump seems to revel in personifying the Dunning-Kruger effect.
Tell yourself that you are a genius. Right away you will probably wonder why and in what way you are a genius. And right away you will have opened your mind up to wonder - and to asking questions. That's a big first step to thinking like a genius, and it might unlock some of your hidden talents.
-- Donald Trump (Think Like a Champion)
In my article "He Knows, You Know," I outline the Dunning-Kruger effect. In short, if you presume you're a genius based on very little information, you likely suffer from thinking you know more than you do. In this case, you will often make rookie mistakes because you think you're an expert when you're actually woefully underinformed.
Mr. Trump, in this and many other quotes from this book, likes to come at things from the aspect of presuming he knows everything and then has an open mind subject to change when presented with new information. Current events show that not only is this not correct, but that's it's also dangerous.
My advice is, instead, presume you know nothing and always question what you do think you know.