First, I need to say that Eric Cressey, despite all his education, apparently can’t do math, as Dr. B pointed out.
Second, to add my two cents, I ended up practicing in an area of law that I did not even know existed until I graduated from law school.
With all due respect to our resident Ph.Ds., some of the “dumbest” people I’ve met had Ph.Ds. Sure, they obviously knew a great deal within their field, but get them to talk about something outside of their field and they were like a deer in headlights. I suppose they weren’t so much “dumb” as the weren’t well rounded.
Some of the more intelligent people I’ve met never bothered to go to college.
But Dr. L has a good point - you think certain professionals are clueless now, imagine what they would be like without the education.