Sir Isaac Newton was asked how he discovered the law of gravity. He replied, "By thinking about it all the time.

He who thinks half-heartedly will not believe in God; but he who really thinks has to believe in God.

In experimental philosophy, propositions gathered from phenomena by induction should be considered either exactly or very nearly true notwithstanding any contrary hypotheses, until yet other phenomena make such propositions either more exact or liable to exceptions.

There are more sure marks of authenticity in the Bible than in any profane history.

Qu. 31. Have not the small Particles of Bodies certain Powers, Virtues or Forces, by which they act at a distance, not only upon the Rays of Light for reflecting, refracting and reflecting them, but also upon one another for producing a great part of the Phænomena of Nature?

By such deductions the law of gravitation is rendered probable, that every particle attracts every other particle with a force which varies inversely as the square of the distance. The law thus suggested is assumed to be universally true.

You sometimes speak of gravity as essential and inherent to matter. Pray do not ascribe that notion to me, for the cause of gravity is what I do not pretend to know, and therefore would take more time to consider of it.