Can you measure it? Can you express it in figures? Can you make a model of it? If not, your theory is apt to be based more upon imagination than upon knowledge.

I have no satisfaction in formulas unless I feel their numerical magnitude.

The more thoroughly I conduct scientific research, the more I believe that science excludes atheism.

If we can't express what we know in the form of numbers, we really don't know much about it.

Nothing can be more fatal to progress than a too confident reliance on mathematical symbols; for the student is only too apt to take the easier course, and consider the formula not the fact as the physical reality.

We all confidently believe that there are at present, and have been from time immemorial, many worlds of life besides our own. . . . [This] may seem wild, and visionary; all I maintain is that it is not unscientific.

If you cannot measure it, then it is not science.