IQ humbug

The weekly email from "Learning How to Learn" contained this:

Book of the Year

Our very favorite, most highly recommended book this year is Boyd: The Fighter Pilot Who Changed the Art of War. This book ranks among our favorite biographies ever. Boyd was a genius level iconoclast (with a measured IQ of 90), and a rebel of the first order, who changed the military’s approach to war and saved countless lives while he was at it. Boyd took on idiocy where ever he found it, whether with bombastic Pentagon generals who were happy to fake important tests, or those who thought they could outgun him in the air. Boyd was so witty, engaging, and fearless in tackling new approaches, and the research behind this extraordinary biography is so artfully done, that it’s a “can’t miss” book for anyone who loves rebels and reading. OODA away!

The highlighted phrase caught my eye.  Wiki has an extensive article on Boyd; but (without reading the book), the best I can do is from a review of this book:

Coram pushes on quickly through Boyd's early school years, covering seemingly inconsequential tidbits such as Boyd's being gifted in math but being pegged with an IQ of only 90. Although the test was suspect, Boyd refused to retake the test and later Boyd used this score to humiliate those who challenged him in a battle of wits.
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Assigned to F-86s, Boyd flies 29 combat sorties in Korea, damages one MiG but gets no kills. After Korea, Boyd returns to the States and is selected to attend the prestigious Fighter Weapons School, graduate school for fighter pilots at Nellis AFB, near Las Vegas. Boyd impresses the FWS instructors and is invited back as in instructor. But Boyd wants to do more than fly and instruct. He wants to "tweak" tactics. Realizing his university education has not equipped him for his tasks, Boyd teaches himself calculus and then formulates equations to demonstrate aircraft performance. To the chagrin of fighter pilots, Boyd adds more academics to FWS, but Boyd is out to teach fighter pilots more than just how to fly: Boyd wants to teach them how to think. But Boyd retains his stick-and-rudder skills, and to prove it, he puts forth the challenge.
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Coram plots out Boyd's continuing quest for more knowledge. Boyd applies for post-graduate schooling and the USAF advises him he can study electrical engineering. Boyd has other ideas. Boyd wins. He attends Georgia Tech, and it is there, studying industrial engineering, that Boyd gets his fingertips on the grail he has been chasing.

Struggling with thermodynamics, Boyd wrestles with the concept of entropy (the amount of energy available to do work) and during a late-night discussion with a fellow student, Boyd realizes it is not airspeed or power that gives the fighter pilot the victory. It is energy.