“Taking experimental results and observations for granted and putting the burden of proof on the theory means taking the observational ideology for granted without having ever examined it.”

New Pathways in Science: Messenger Lectures 1934 (1947), p. 211.

Notes And Comments, p. 179
Dark Age Ahead (2004)

As quoted in "Annals of Science II-DNA" by Horace Freeland Judson in The New Yorker (4 December 1978), p. 132

Address to his branch and flight control team on the Monday morning following the Apollo 1 disaster (30 January 1967), known as "The Kranz Dictum"; as published in Failure Is Not An Option : Mission Control from Mercury to Apollo 13 and Beyond (2000) by Gene Kranz, p. 204. The phrase "tough and competent" was echoed by NASA Director Sean O'Keefe following the Space Shuttle Columbia disaster, adding that "these words are the price of admission to the ranks of NASA, and we should adopt it that way."
Context: Spaceflight will never tolerate carelessness, incapacity, and neglect. Somewhere, somehow, we screwed up. It could have been in design, build, or test. Whatever it was, we should have caught it.
We were too gung ho about the schedule and we locked out all of the problems we saw each day in our work. Every element of the program was in trouble and so were we. The simulators were not working, Mission Control was behind in virtually every area, and the flight and test procedures changed daily. Nothing we did had any shelf life. Not one of us stood up and said, "Dammit, stop!"
I don't know what Thompson's committee will find as the cause, but I know what I find. We are the cause! We were not ready! We did not do our job. We were rolling the dice, hoping that things would come together by launch day, when in our hearts we knew it would take a miracle. We were pushing the schedule and betting that the Cape would slip before we did.
From this day forward, Flight Control will be known by two words: "Tough and Competent." Tough means we are forever accountable for what we do or what we fail to do. We will never again compromise our responsibilities. Every time we walk into Mission Control we will know what we stand for.
Competent means we will never take anything for granted. We will never be found short in our knowledge and in our skills. Mission Control will be perfect.
When you leave this meeting today you will go to your office and the first thing you will do there is to write "Tough and Competent" on your blackboards. It will never be erased. Each day when you enter the room these words will remind you of the price paid by Grissom, White, and Chaffee. These words are the price of admission to the ranks of Mission Control.

"Matter" in Man's Right to Knowledge, 2nd series (1954), p. 10; also in Writings on Physics and Philosophy‎ (1994) edited by Charles Paul P. Enz and Karl von Meyenn
Context: In the new pattern of thought we do not assume any longer the detached observer, occurring in the idealizations of this classical type of theory, but an observer who by his indeterminable effects creates a new situation, theoretically described as a new state of the observed system. In this way every observation is a singling out of a particular factual result, here and now, from the theoretical possibilities, therefore making obvious the discontinuous aspect of physical phenomena.
Nevertheless, there remains still in the new kind of theory an objective reality, inasmuch as these theories deny any possibility for the observer to influence the result of a measurement, once the experimental arrangement is chosen. Therefore particular qualities of an individual observer do not enter into the conceptual framework of the theory.

Source: Science and Statistics (1976), p. 792

5th Public Talk Saanen (26th July 1970); also in "Fear and Pleasure", The Collected Works, Vol. X
1970s
Context: Do you decide to observe? Or do you merely observe? Do you decide and say, "I am going to observe and learn"? For then there is the question: "Who is deciding?" Is it will that says, "I must"? And when it fails, it chastises itself further and says, "I must, must, must"; in that there is conflict; therefore the state of mind that has decided to observe is not observation at all. You are walking down the road, somebody passes you by, you observe and you may say to yourself, "How ugly he is; how he smells; I wish he would not do this or that". You are aware of your responses to that passer-by, you are aware that you are judging, condemning or justifying; you are observing. You do not say, "I must not judge, I must not justify". In being aware of your responses, there is no decision at all. You see somebody who insulted you yesterday. Immediately all your hackles are up, you become nervous or anxious, you begin to dislike; be aware of your dislike, be aware of all that, do not "decide" to be aware. Observe, and in that observation there is neither the "observer" nor the "observed" — there is only observation taking place. The "observer" exists only when you accumulate in the observation; when you say, "He is my friend because he has flattered me", or, "He is not my friend, because he has said something ugly about me, or something true which I do not like." That is accumulation through observation and that accumulation is the observer. When you observe without accumulation, then there is no judgement.

Speech at Salthill (5 October 1864).
1860s

"The Use of Models: Experience," 1969