Maxwell, the great physicist, once said, "To measure is to know," and his words are often taken as a motto by other sciences. What Maxwell probably meant was "To know how to measure is to know," or even better, "To know what to measure is to know"... Knowing what is worth measuring, the physicist can narrow his experimental field to those matters. In a sense, physics is the science of those things a physicist can measure.

The Psychology of Computer Programming: Silver Anniversary Edition by Gerald M. Weinberg

ISBN: 0932633420 Page: 36, Chapter 3 This book is available from Amazon