# Quote — Henri Poincaré, The Value of Science

> 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.

- 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)
- Original (fr): Il ne faut pas comparer la marche de la science aux transformations d’une ville, où les édifices vieillis sont impitoyablement jetés à bas pour faire place aux constructions nouvelles, mais à l’évolution continue des types zoologiques qui se développent sans cesse et finissent par devenir méconnaissables aux regards vulgaires, mais où un œil exercé retrouve toujours les traces du travail antérieur des siècles passés. Il ne faut donc pas croire que les théories démodées ont été stériles et vaines.
- Source: [Wikiquote](https://en.wikiquote.org/wiki/Henri_Poincar%C3%A9#Introduction) ([CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/))
- Quote page: https://www.leafyquotes.com/henri-poincare/the-value-of-science/the-advance-of-science

## 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)

> If all the parts of the universe are interchained in a certain measure, any one phenomenon will not be the effect of a single cause, but the resultant of causes infinitely numerous; it is, one often says, the consequence of the state of the universe the moment before.

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