Are not gross bodies and light convertible into one another; and may not bodies receive much of their activity from the particles of light which enter into their composition? The changing of bodies into light, and light into bodies, is very conformable to the course of Nature, which seems delighted with transmutations.

I shall not mingle conjectures with certainties.

The Synthesis consists in assuming the Causes discovered and established as Principles, and by them explaining the Phænomena proceeding from them, and proving the Explanations.

All knowledge and understanding of the Universe was no more than playing with stones and shells on the seashore of the vast imponderable ocean of truth.

Our present work sets forth mathematical principles of philosophy. For the basic problem of philosophy seems to be to discover the forces of nature from the phenomena of motions and then to demonstrate the other phenomena from these forces. It is to these ends that the general propositions in books 1 and 2 are directed, while in book 3 our explanation of the system of the world illustrates these propositions.

Now the smallest Particles of Matter may cohere by the strongest Attractions, and compose bigger Particles of weaker Virture.... There are therefore Agents in Nature able to make the Particles of Bodies stick together by very strong Attraction. And it is the Business of experimental Philosophy to find them out.

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