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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 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.

William Thomson#1

ScienceMathematicsMeasurementDataKnowledgeTruth

About this quote

What does it mean?
True scientific knowledge requires quantification; without numbers, understanding remains incomplete and immature.
In plain terms
If you cant measure it, you do not truly know it yet.
What can you take from it?
Measurement is the key to turning vague knowledge into science.

Where it applies

  • evaluating claims
  • scientific research
  • assessing expertise

Putting it to work

  • data collection
  • defining metrics
  • testing theories

Questions to consider

  • What can you measure about your work?
  • Is unmeasured knowledge useless?

Another view

Some valuable human experiences cannot be measured numerically.

More from William Thomson

  1. There cannot be a greater mistake than that of looking superciliously upon the practical applications of science. The life and soul of science is its practical…

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  2. Quaternions came from Hamilton after his really good work had been done, and though beautifully ingenious, have been an unmixed evil to those who have touched …

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  3. Heavier-than-air flying machines are impossible.

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