Two left-handed gloves don't make a pair. Two half-truths don't make a truth.
(Multatuli [Eduard Douwer Dekker] (1820-1887), Dutch writer, civil servant. "Idee 2," The Oyster and the Eagle: Selected Aphorisms and Parables of Multatuli (1872), trans. by E. M. Beekman, U of Mass. Press (1974).)
Belief in the truth commences with the doubting of all those "truths" we once believed.
(Friedrich Nietzsche (1844-1900), German philosopher, classical scholar, critic of culture. Friedrich Nietzsche, Sämtliche Werke: Kritische Studienausgabe, vol. 2, p. 387, eds. Giorgio Colli and Mazzino Montinari, Berlin, de Gruyter (1980). Mixed Opinions and Maxims, aphorism 20, "Truth Will Have No Other Gods Alongside It," (1879).)
For though we love both the truth and our friends, piety requires us to honor the truth first.
(Aristotle (384-322 B.C.), Greek philosopher. Nicomachean Ethics, bk. 1, ch. 6, trans. by Terence Irwin (1985).
Often quoted (from the Latin) "Plato is dear to me, but dearer still is truth." Aristotle, who spent 20 years at Plato's Academy as pupil and teacher, referred to his philosophical colleagues at the Academy as "friends.")