If I am anything, which I highly doubt, I have made myself so by hard work.

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.

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.

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

The best way to understanding is a few good examples.

I shall not mingle conjectures with certainties.

Blind metaphysical necessity, which is certainly the same always and every where, could produce no variety of things. All that diversity of natural things which we find suited to different times and places could arise from nothing but the ideas and will of a Being, necessarily existing.