The qualities of bodies, which admit neither intension nor remission of degrees, and which are found to belong to fill bodies within the reach of our experiments, are to be esteemed the universal qualities of all bodies whatsoever.

An object that is at rest will tend to stay at rest. An object that is in motion will tend to stay in motion.

When two forces unite, their efficiency double.

How came the bodies of animals to be contrived with so much art, and for what ends were their several parts? Was the eye contrived without skill in Opticks, and the ear without knowledge of sounds?...and these things being rightly dispatch’d, does it not appear from phænomena that there is a Being incorporeal, living, intelligent...?

The daily disappearance and the subsequent rise of the sun appeared to many of the ancients as a true resurrection; thus, while the east came to be regarded as the source of light and warmth, happiness and glory, the west was associated with darkness and chill, decay and death. This led to the custom of burying the dead so as to face the east when they rose again, and of building temples and shrines with an opening toward the east. To effect this, Vitruvius, two thousand years ago, gave precise rules, which are still followed by Christian architects.

All my discoveries have been made in answer to prayer.

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.