Philosophy is such an impertinently litigious lady that a man had as good be engaged in lawsuits as have to do with her.

Gravity explains the motions of the planets, but it cannot explain who sets the planets in motion.

My principal method for defeating error and heresy is by establishing the truth. One purposes to fill a bushel with tares, but if I can fill it first with wheat, I may defy his attempts.

The best and safest way of philosophising seems to be, first to enquire diligently into the properties of things, and to establish those properties by experiences [experiments] and then to proceed slowly to hypotheses for the explanation of them. For hypotheses should be employed only in explaining the properties of things, but not assumed in determining them; unless so far as they may furnish experiments.

God created everything by number, weight and measure.

...from the same principles, I now demonstrate the frame of the System of the World.

To explain all nature is too difficult a task for any one man or even for any one age. Tis much better to do a little with certainty & leave the rest for others that come after than to explain all things by conjecture without making sure of any thing.