Here is what William Thompson, better known as Lord Kelvin, once said about measure :
« I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the state of Science, whatever the matter may be. »
William Thompson, Lecture on “Electrical Units of Measurement” (3 May 1883)
I found this quote in an early essay of the French philosopher Gaston Bachelard on what he calls “approached knowledge” (Essai sur la connaissance approchée, 1927). For him, measures cannot be considered for themselves, and he does not agree with Thompson on this point. According to him, the fact that a measure is precise enough gives us the illusion that something exists or just became real.
I quote in French, as I could find a English edition nearby, the page numbers refer to the book published by Vrin.
« Et pourtant, que ce soit dans la mesure ou dans une comparaison qualitative, il ...