John R. Platt (1964) " Science, Strong Inference -- Proper Scientific Method (The New Baconians) http://256.com/gray/docs/strong_inference.html. In: Science Magazine 16 October 1964, Volume 146, Number 3642. Cited in: Gerald Weinberg (1975) Introduction to General Systems Thinking. p. 1, and in multiple other sources.
“For although it is certainly true that quantitative measurements are of great importance, it is a grave error to suppose that the whole of experimental physics can be brought under this heading. We can start measuring only when we know what to measure: qualitative observation has to precede quantitative measurement, and by making experimental arrangements for quantitative measurements we may even eliminate the possibility of new phenomena appearing.”
in his memoirs, as quoted by [Jean Matricon, G. Waysand, Charles Glashausser, The cold wars: a history of superconductivity, Rutgers University Press, 2003, 0813532957, 18]
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Hendrik Casimir 1
Dutch physicist 1909–2000Related quotes
Source: Information, The New Language of Science (2003), Chapter 24, Bits, Bucks, Hits and Nuts, Information theory beyond Shannon, p. 221

"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.

"Mathematical Contributions to the Theory of Evolution III: Regression, Heredity and Panmixia", Philosophical Transactions of the Royal Society, Series A, Vol. 187 (1896) p. 259.

“It is not easy to measure the ocean, but we can be measured by it, confront it, and be in it.”
Source: The Archaic Revival
Introduction
Higher Mathematics for Chemical Students (1911)

"Matteo" in Concerning the New Star (1606)
Other quotes

Out of Control: The New Biology of Machines, Social Systems and the Economic World (1995), New Rules for the New Economy: 10 Radical Strategies for a Connected World (1999)