Source: The Human Side of Enterprise (1960), p. 11 (2006; 13)
“Every managerial act rests on assumptions, generalizations, and hypotheses — that is to say, on theory. Our assumptions are frequently implicit, sometimes quite unconscious, often conflicting; nevertheless, they determine our predictions that if we do a, b will occur. Theory and practice are inseparable.”
Source: The Human Side of Enterprise (1960), p. 6 (2006; 8)
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Douglas McGregor 22
American professor 1906–1964Related quotes
Source: The Human Side of Enterprise (1960), p. 18 (2006; 24)

Source: "The Origins of Organizational Theory," 2005, p. 143

“A theory is only as good as its assumptions.”
If the premises are false, the theory has no real scientific value. The only scientific criterion for judging the validity of a scientific theory is a confrontation with the data of experience.
[Maurice Allais, L'anisotropie de l'espace. La nécessaire révision de certains postulats des théories contemporaines. Les données de l'expérience, Editions Clément Juglar, Paris, 1997, 591, 2-908735-09-1]
Source: The Managerial Revolution, 1941, p. 7, as cited in: Albert Lepawsky (1949), Administration, p. 12-13
“Behind every managerial decision or action are assumptions about human nature and human behavior.”
Source: The Human Side of Enterprise (1960), p. 33

“Some tacit assumptions of the theory of insufficiency remain problematic.”
Source: Who Is Man? (1965), Ch. 5<!-- Pathos, p. 91 -->
Context: Being is either open to, or dependent on, what is more than being, namely, the care for being, or it is a cul-de-sac, to be explained in terms of self-sufficiency. The weakness of the first possibility is in its reference to a mystery; the weakness of the second possibility is in its pretension to offer a rational explanation.
Nature, the sum of its laws, may be sufficient to explain in its own terms how facts behave within nature; it does not explain why they behave at all. Some tacit assumptions of the theory of insufficiency remain problematic.

“Theory and practice sometimes clash. And when that happens, theory loses. Every single time.”
Message to Linux kernel mailing list, 2009-03-25, Torvalds, Linus, 2009-03-25 http://lkml.org/lkml/2009/3/25/632,
2000s, 2009

Source: Democracy Realizedː The Progressive Alternative (1998), p. 15