for some men are no less convinced of what they think than others of what they know
 Aristotle, Nicomachean Ethics (c. 334 BC - 330 BC). copy citation

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Author Aristotle
Source Nicomachean Ethics
Topic thought
Date c. 334 BC - 330 BC
Language English
Reference
Note Translated by W. D. Ross
Weblink http://classics.mit.edu/Aristotle/nicomachaen.mb.txt

Context

“If, then, the notion is that owing to their weak conviction those who have opinion are more likely to act against their judgement than those who know, we answer that there need be no difference between knowledge and opinion in this respect; for some men are no less convinced of what they think than others of what they know; as is shown by the of Heraclitus. But (a) , since we use the word 'know' in two senses (for both the man who has knowledge but is not using it and he who is using it are said to know) , it will make a difference whether, when a man does what he should not, he has the knowledge but is not exercising it, or is exercising it;” source