“Galaxies are observed to be simple systems following laws that result from scale-invariant dynamics which do not emanate from the haphazard merging history of halos of exotic dark matter.”

—  Pavel Kroupa

Do astronomical data contradict the existence of dynamically relevant cold or dark matter? (seminar talk at Columbia U. Astronomy Department), Pavel Kroupa, 16 Oct. 2014 http://www.astro.columbia.edu/event?eid=185,

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Pavel Kroupa 8
Australian astrophysicist 1963

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“A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works and cannot be patched up to make it work. You have to start over, beginning with a working simple system.”

John Gall (1925–2014) American physician

Source: General systemantics, an essay on how systems work, and especially how they fail..., 1975, p. 65, cited in: Grady Booch (1991) Object oriented design with applications. p. 11

“The idea that theorems follow from the postulates does not correspond to simple observation.”

Richard Hamming (1915–1998) American mathematician and information theorist

The Unreasonable Effectiveness of Mathematics (1980)
Context: The idea that theorems follow from the postulates does not correspond to simple observation. If the Pythagorean theorem were found to not follow from the postulates, we would again search for a way to alter the postulates until it was true. Euclid's postulates came from the Pythagorean theorem, not the other way around.

“A complex system that works is invariably found to have evolved from a simple system that worked. The inverse proposition also appears to be true: A complex system designed from scratch never works and cannot be made to work. You have to start over, beginning with a working simple system.”

John Gall (1925–2014) American physician

Source: General systemantics, an essay on how systems work, and especially how they fail..., 1975, p. 71. This statement is known as Gall's law

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