“Exaggeration of confidence,” he said, “is a fault in people who don’t know their business.”
This is an early statement of what would come to be known as the Dunning–Kruger effect.
Source: Tactics of Mistake (1971), Chapter 20 (p. 315).
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Gordon R. Dickson 19
Canadian-American science fiction writer 1923–2001Related quotes

“People who are busy and happy don’t write diaries; they are too busy living.”
Source: Friday (1982), Chapter 33 (p. 353)
“Don’t lose your temper,” said Ruell evenly. “It’s your worst fault, except for ignorance.”
Source: A for Anything (1959), Chapter 7 (p. 88)

Crucible of Creativity (2005)
Context: Anonymity relieves refactoring friction. Have learned that people want to sign things. But try to write in a way where you don’t have to know who said it. But when someone who is not in a giving mood uses anonymity (spammers), that abuse can drive us away from anonymity. But I hope we can drive the ill-intended out without having to give up the openness.

“Dilettantes,’ Art3mis said. ‘It’s their own fault for not knowing all thelyrics by heart.”
Source: Ready Player One
“People who think they’re generous to a fault usually think that’s their only fault.”
Source: On the Contrary (1964), Ch. 7