“Measure what is measurable, and make measurable what is not so.”

“Physical strength is measured by what we carry.
Inner strength is measured by what we can bear.”

“What has philosophy got to do with measuring anything? It's the mathematicians you have to trust, and they measure the skies like we measure a field.”

“What's measured improves”

“What people believe is a measure of what they suffer.”

“For although it is certainly true that quantitative measurements are of great importance, it is a grave error to suppose that the whole of experimental physics can be brought under this heading. We can start measuring only when we know what to measure: qualitative observation has to precede quantitative measurement, and by making experimental arrangements for quantitative measurements we may even eliminate the possibility of new phenomena appearing.”

“The first step is to measure whatever can easily be measured. This is OK as far as it goes. The second step is to disregard that which can't be easily measured or to give it an arbitrary quantitative value. This is artificial and misleading. The third step is to presume that what can't be measured easily really isn't important. This is blindness. The fourth step is to say that what can't be easily measured really doesn't exist. This is suicide.”

“What gets measured gets improved.”

“Was it possible to measure what the heart felt?”

“What gets measured gets done.”