“With regard to matters requiring thought: the less people know and understand about them, the more positively they attempt to argue concerning them.”
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Galileo Galilei 70
Italian mathematician, physicist, philosopher and astronomer 1564–1642Related quotes

Introduction to the 2002 edition, p. 2
The Heart of Change, (2002)

“Worry less about what other people think about you, and more about what you think about them.”

"The Heart of the Matter"
Song lyrics, The End of the Innocence (1989)
Source: What is Political Philosophy (1959), p. 68

Sun-Faced Buddha, Moon-Faced Buddha lecture at the Zen Mountain Center (17 August 1971) http://suzukiroshi.sfzc.org/archives/index.cgi/710817V.html
Context: Communication is — start by understanding — your own understanding about people. Even though you want them to understand you, you know, it is — unless you understand people, it is almost impossible. Don't you think so? Only when you understand people, they may understand you. So even though you do not say anything, if you understand people there is some communication.