Hint: not by discussing IQ
.. Virtually none of them (need to) say it. There are a few prominent exceptions, of talented people who annoyingly go out of their way to announce that fact. Muhammad Ali is the charming extreme exception illustrating the rule: he said he was The Greatest, and was. Most greats don’t need to say so.* It would be like Roger Federer introducing himself with, “You know, I’m quite graceful and gifted.” Or Meryl Streep asking, “Have you seen my awards?”
.. 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
.. To read books seriously is to be staggered by the knowledge of how many more books will remain beyond your ken. It’s like looking up at the star-filled sky.
.. 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.