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.
我常说，当你能测量你所说的事物并以数字表达它时，说明关于这个事物你的确是知道一些的，但是当你无法测量它、无法以数字表达它时，说明你的所知就是贫乏的、难以令人满意的：它可能是知识的开端，但你几乎没有从思想上达到科学的阶段，无论这个事物是什么。