Famous quotes containing the words primary and/or key:
“A fact is a proposition of which the verification by an appeal to the primary sources of our knowledge or to experience is direct and simple. A theory, on the other hand, if true, has all the characteristics of a fact except that its verification is possible only by indirect, remote, and difficult means.”
—Chauncey Wright (1830–1875)
“Woe to you lawyers! For you have taken away the key of knowledge; you did not enter yourselves, and you hindered those who were entering.”
—Bible: New Testament, Luke 11:52.