From Endgame Enigma by James P. Hogan

Paula (physicist) had said, "You see, the whole problem with the 
world is that fools and fanatics are always so certain of 
themselves, but wiser people so full of doubts."
"Who said that?" Earnshaw (intelligence agent) 
had asked.
"Bertrand Russell." She'd waited a moment while he thought it over. 
"A philosopher." (Paula)
"Philosopher, eh?" (Earnshaw)
"Sometime back in the last century." (Paula)
"Just like that?" (Earnshaw)
"What do you mean, 'just like that'?" (Paula)
"That's how he said it, just like that?" (Earnshaw)
"I guess so." (Paula)
Earnshaw had eyed her skeptically, then asked, "So how come he 
didn't put 'I think' at the end of it?"


......
Thinking back over everything that had happened in the six months 
since it had all begun, she (Paula) could see now how 
systematically and ruthlessly she had been deceived.  And what 
had made the deception possible was her own intellectual conceit 
and a conviction of infallibility that it had never crossed her 
mind to question.  The irony was that it was she, the scientist, 
who had taken her assumptions for granted; Earnshaw, the cavalier, 
had questioned every assumption.

.....
"The whole problem with the world is that fools and fanatics are 
always so certain of themselves, but wiser people are full of 
doubts," she remembered quoting pompously to Earnshaw on their 
voyage up.  "How come he didn't add 'I think'?" Earnshaw had asked.  
It had taken her this long to understand what he'd meant.

....
She remembered a stage magician she met at a party once, who had 
talked about how easily some scientists were fooled by claims of 
paranormal phenomena.
"Basically it plays upon conceit," the conjurer had said.  "They 
don't like to think they can be taken in by 'mere entertainers.'  
Therefore their subconscious thinking runs something like: If 'I' 
can't spot the trick, then there can't be a trick.  The only 
choice they've got left then is to accept what they think they've 
seen as genuine."

....
".. Science is realism -- eliminating wishful thinking.  If you can't 
do that, you can't begin.  You'll never know what truth is...."