“We begin to wonder if it is due to the fact that we don't know enough. But it can't be that. Because in terms of accumulated knowledge we know more today than men have known in any period of human history. We have the facts at our disposal. We know more about mathematics, about science, about social science, and philosophy than we've ever known in any period of the world's history. So it can't be because we don't know enough. And then we wonder if it is due to the fact that our scientific genius lags behind. That is, if we have not made enough progress scientifically. Well then, it can't be that. For our scientific progress over the past years has been amazing.”

Armistice Day speech (11 November 1948), published in Omar Bradley's Collected Writings, Volume 1 (1967)

[2000, Warranted Christian Belief, 9780195131925, 217, http://www.ccel.org/ccel/plantinga/warrant3.vi.ii.iv.ii.html]

Source: Information, The New Language of Science (2003), Chapter 2, The Spell of Democritus, Why information will transform physics, p. 11

Armistice Day speech (11 November 1948), published in Omar Bradley's Collected Writings, Volume 1 (1967).
Context: We have men of science, too few men of God. We have grasped the mystery of the atom and rejected the Sermon on the Mount. The world has achieved brilliance without conscience. Ours is a world of nuclear giants and ethical infants. We know more about war than we know about peace, more about killing than we know about living. If we continue to develop our technology without wisdom or prudence, our servant may prove to be our executioner.

Department of Defense news briefing (12 February 2002)
Variant:
Now what is the message there? The message is that there are no "knowns." There are things we know that we know. There are known unknowns. That is to say there are things that we now know we don't know. But there are also unknown unknowns. There are things we do not know we don't know. So when we do the best we can and we pull all this information together, and we then say well that's basically what we see as the situation, that is really only the known knowns and the known unknowns. And each year, we discover a few more of those unknown unknowns.
:It sounds like a riddle. It isn't a riddle. It is a very serious, important matter.
:There's another way to phrase that and that is that the absence of evidence is not evidence of absence. It is basically saying the same thing in a different way. Simply because you do not have evidence that something exists does not mean that you have evidence that it doesn't exist. And yet almost always, when we make our threat assessments, when we look at the world, we end up basing it on the first two pieces of that puzzle, rather than all three.
:* Extending on his earlier comments in a press conference at NATO Headquarters, Brussels, Belgium (6 June 2002) http://www.nato.int/docu/speech/2002/s020606g.htm
2000s

Source: The Madness of Crowds: Gender, Race and Identity (2019)

"How To Build A Universe That Doesn't Fall Apart Two Days Later" (1978)

An Outline of Philosophy Ch.15 The Nature of our Knowledge of Physics (1927)
1920s
Context: Physics is mathematical not because we know so much about the physical world, but because we know so little: it is only its mathematical properties that we can discover.