# Quote — Henri Poincaré, The Value of Science

> When navigators... determine a ... they must... calculate Paris time...[with] a chronometer set for Paris. The qualitative problem of simultaneity is made to depend upon the quantitative problem of the measurement of time.

- Author: [Henri Poincaré](https://www.leafyquotes.com/henri-poincare.md)
- Book: [The Value of Science](https://www.leafyquotes.com/henri-poincare/the-value-of-science.md)
- Source: [Wikiquote](https://en.wikiquote.org/wiki/Henri_Poincar%C3%A9#Ch._2:_The_Measure_of_Time) ([CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/))
- Topics: [time](https://www.leafyquotes.com/topics/time.md)
- Quote page: https://www.leafyquotes.com/henri-poincare/the-value-of-science/when-navigators-determine

## More from this book

> Does the harmony the human intelligence thinks it discovers in nature exist outside of this intelligence? No, beyond doubt, a reality completely independent of the mind which conceives it, sees or feels it, is an impossibility. A world as exterior as that, even if it existed, would for us be forever inaccessible.

[Quote page](https://www.leafyquotes.com/henri-poincare/the-value-of-science/does-the-harmony.md)

> Time and Space … It is not nature which imposes them upon us, it is we who impose them upon nature because we find them convenient.

[Quote page](https://www.leafyquotes.com/henri-poincare/the-value-of-science/time-and-space.md)

> The advance of science is not comparable to the changes of a city, where old edifices are pitilessly torn down to give place to new, but to the continuous evolution of zoologic types which develop ceaselessly and end by becoming unrecognizable to the common sight, but where an expert eye finds always traces of the prior work of the centuries past. One must not think then that the old-fashioned theories have been sterile or vain.

[Quote page](https://www.leafyquotes.com/henri-poincare/the-value-of-science/the-advance-of-science.md)