William Thomson, 1st Baron Kelvin · 1907

c. 1907Exact date was not recorded in the sourceDirect quote68% confidence

“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 meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter may be.”

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Captured 2026-08-17 from Wikiquote (en). The archived copy is preserved so this citation survives link rot.