When You Cannot Measure, Your

If You Cannot Measure It, Then It Is Not Science.

When You Can Measure What You Are Speaking About, And Express It In Numbers, You Know Something About It.

Suppose That You Could Mark The Molecules In A Glass Of Water; Then Pour The Contents Of The Glass Into The Ocean And Stir The Latter Throughly So As To Distribute The Marked Molecules Uniformly Throughout The Seven Seas; If Then You Took A Glass Of Water Anywhere Out Of The Ocean, You Would Find In It About A Hundred Of Your Marked Molecules.

In Physical Science A First Essential Step In The Direction Of Learning Any Subject Is To Find Principles Of Numerical Reckoning And Practicable Methods For Measuring Some Quality Connected With It. 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.

I Have Not The Smallest Molecule Of Faith In Aerial Navigation Other Than Ballooning, Or Of The Expectation Of Good Results From Any Of The Trials We Heard Of. So You Will Understand That I Would Not Care To Be A Member Of The Aeronautical Society.