“Sincerity is that whereby self-completion is effected, and its way is that by which man must direct himself.”
Source: The Doctrine of the Mean
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Confucius 269
Chinese teacher, editor, politician, and philosopher -551–-479 BCRelated quotes

Source: Aphorisms and Reflections (1901), p. 234

[Review of Electric Waves by H. M. Macdonald, 19 February 1903, 67, 1738, 361–364, https://babel.hathitrust.org/cgi/pt?id=umn.319510002995080;view=1up;seq=421] (p. 363)

Source: 1970s, Take Today : The Executive as Dropout (1972), p. 90

Source: The Modern Corporation and Private Property. 1932/1967, p. 2 (1967, p. 4)

“A man defines himself by his make-believe as well as by his sincere impulses.”
Un homme se définit aussi bien par ses comédies que par ses élans sincères.
http://books.google.com/books?id=9FgoAQAAIAAJ&q=%22un+homme+se+d%C3%A9finit+aussi+bien+par+ses+com%C3%A9dies+que+par+ses+%C3%A9lans+sinc%C3%A8res%22&pg=PA25#v=onepage
The Myth of Sisyphus (1942), An Absurd Reasoning

“No man can produce great things who is not thoroughly sincere in dealing with himself.”
Literary Essays, vol. II (1870–1890), Rousseau and the Sentimentalists

as quoted in "The man who got it right," The New York Review of Books, Volume 60, Number 13, August 15, 2013, p. 72