# Quote — Ernst Mach, The Science of Mechanics

> Let us... examine the point on which Newton, apparently with sound reasons, rests his distinction of absolute and relative motion. If the earth is affected with an absolute rotation about its axis, centrifugal forces are set up in the earth: it assumes an oblate form, the acceleration of gravity is diminished at the equator, the plane of Foucault's pendulum rotates, and so on. All these phenomena disappear if the earth is at rest and the other heavenly bodies are affected with absolute motion round it, such that the same relative rotation is produced. This is, indeed, the case, if we start ab initio from the idea of absolute space. But if we take our stand on the basis of facts, we shall find we have knowledge only of relative spaces and motions. Relatively, not considering the unknown and neglected medium of space, the motions of the universe are the same whether we adopt the Ptolemaic or the Copernican mode of view. Both views are, indeed, equally correct; only the latter is more simple and more practical. The universe is not twice given, with an earth at rest and an earth in motion; but only once, with its relative motions, alone determinable. It is, accordingly, not permitted us to say how things would be if the earth did not rotate. We may interpret the one case that is given us, in different ways. If, however, we so interpret it that we come into conflict with experience, our interpretation is... wrong. The principles of mechanics can, indeed, be so conceived, that even for relative rotations s arise.

- Author: [Ernst Mach](https://www.leafyquotes.com/ernst-mach.md)
- Book: [The Science of Mechanics](https://www.leafyquotes.com/ernst-mach/the-science-of-mechanics.md)
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- Quote page: https://www.leafyquotes.com/ernst-mach/the-science-of-mechanics/let-us-examine

## More from this book

> [I]t is necessary to make a distinction between mechanical experience and mechanical science... If we carefully examine the ancient Egyptian and Assyrian monuments, we shall find there pictorial representations of many kinds of implements and mechanical contrivances... long before theory was dreamed of, implements, machines, mechanical experiences, and mechanical knowledge were abundant.

[Quote page](https://www.leafyquotes.com/ernst-mach/the-science-of-mechanics/i-t-is-necessary.md)

> The questions here dealt with have occupied me since my earliest youth, when my interest for them was powerfully stimulated by the beautiful introductions of Lagrange to... his Analytic Mechanics, as well as by the lucid and lively tract of Jolly, Principien der Mechanik (...1852). If Duehring's estimable work, Kritische Geschichte der Principien der Mechanik (...1873), did not particularly influence me, it was that at the time of its appearance, my ideas had been... published. ...[T]he reader will... find many points of agreement between Dühring's criticisms and those here expressed.

[Quote page](https://www.leafyquotes.com/ernst-mach/the-science-of-mechanics/the-questions-here.md)

> An instinctive, irreflective knowledge of the processes of nature will doubtless always precede the scientific, conscious apprehension, or investigation, of phenomena. The former is the outcome of the relation in which the processes of nature stand to the satisfaction of our wants.

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