科學

Lord Kelvin：「 I often say that when you can measure something that you are speaking about, 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 the meager 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 might be. 」

當你能測量你所說的事物並以數字表達它時，說明關於這個事物你的確是知道一些的，但是當你無法測量它、無法以數字表達它時，說明你的所知就是貧乏的、難以令人滿意的：它可能是知識的開端，但你幾乎沒有從思想上達到科學的階段，無論這個事物是什麼。