“Concepts that have proven useful in ordering things easily achieve such authority over us that we forget their earthly origins and accept them as unalterable givens.”

Letter to the Cabinet (January 1942), quoted in Paul Addison, The Road to 1945 (London: Pimlico, 1994), pp. 202-203
1940s

Writers at Work interview (1958)

On National-Socialism, Bolshevism &amp; Democracy (September 10, 1938) http://www.jewishvirtuallibrary.org/joseph-goebbels-on-national-socialism-bolshevism-and-democracy <br class="br">1930s

Obituary for physicist and philosopher Ernst Mach (Nachruf auf Ernst Mach), Physikalische Zeitschrift 17 (1916), p. 101
1910s
Context: How does it happen that a properly endowed natural scientist comes to concern himself with epistemology? Is there not some more valuable work to be done in his specialty? That's what I hear many of my colleagues ask, and I sense it from many more. But I cannot share this sentiment. When I think about the ablest students whom I have encountered in my teaching — that is, those who distinguish themselves by their independence of judgment and not just their quick-wittedness — I can affirm that they had a vigorous interest in epistemology. They happily began discussions about the goals and methods of science, and they showed unequivocally, through tenacious defense of their views, that the subject seemed important to them.
Concepts that have proven useful in ordering things easily achieve such authority over us that we forget their earthly origins and accept them as unalterable givens. [Begriffe, welche sich bei der Ordnung der Dinge als nützlich erwiesen haben, erlangen über uns leicht eine solche Autorität, dass wir ihres irdischen Ursprungs vergessen und sie als unabänderliche Gegebenheiten hinnehmen. ] Thus they might come to be stamped as "necessities of thought," "a priori givens," etc. The path of scientific progress is often made impassable for a long time by such errors. [Der Weg des wissenschaftlichen Fortschritts wird durch solche Irrtümer oft für längere Zeit ungangbar gemacht. ] Therefore it is by no means an idle game if we become practiced in analysing long-held commonplace concepts and showing the circumstances on which their justification and usefulness depend, and how they have grown up, individually, out of the givens of experience. Thus their excessive authority will be broken. They will be removed if they cannot be properly legitimated, corrected if their correlation with given things be far too superfluous, or replaced if a new system can be established that we prefer for whatever reason.

Book VII, 1328b.4
Politics

Source: The Christian Agnostic (1965), p.77-78, (Paul Tillich: The Shaking of the Foundations. 1963. Pelican Books. p. 164

The Ethics of Belief (1877), The Weight Of Authority
Context: In regard, then, to the sacred tradition of humanity, we learn that it consists, not in propositions or statements which are to be accepted and believed on the authority of the tradition, but in questions rightly asked, in conceptions which enable us to ask further questions, and in methods of answering questions. The value of all these things depends on their being tested day by day. The very sacredness of the precious deposit imposes upon us the duty and the responsibility of testing it, of purifying and enlarging it to the utmost of our power. He who makes use of its results to stifle his own doubts, or to hamper the inquiry of others, is guilty of a sacrilege which centuries shall never be able to blot out. When the labours and questionings of honest and brave men shall have built up the fabric of known truth to a glory which we in this generation can neither hope for nor imagine, in that pure and holy temple he shall have no part nor lot, but his name and his works shall be cast out into the darkness of oblivion for ever.

"On the Dilemmas of the Christian Legacy"