I am often both appalled and amazed at how stupidly many smart people act.
No detectable common sense at all :-/
Me too. I came up with a quote on the matter back in college: “Never confuse intelligence and intellectualism.” “Intellectuals” are quite often absurdly stupid.
More recently, I started playing Dungeons and Dragons (which is great, btw), and that gave me some more insight as well. There are different ability stats your character can have, and “Intelligence” and “Wisdom” are separate. So, you can be highly intelligent but incredibly lacking in wisdom.
And that’s how I would describe a lot of professors and students I knew in college. Really smart people who excelled in certain areas of study (intelligence), but when it came to something like basic economics and politics (wisdom), they were completely insane and clueless. So, I think D&D has it right: intelligence and wisdom are two different things, and a person can be high in one and low in the other.
As George Orwell said, some ideas are so stupid that only an intellectual could believe them.