When two forces unite, their efficiency double. — Isaac Newton

Every particle of matter is attracted by or gravitates to every other particle of matter with a force inversely proportional to the squares of their distances. — Isaac Newton

I have explained the phenomena of the heavens and of our sea by the force of gravity, but I have not yet assigned a cause to gravity. — Isaac Newton

It is reasonable that forces directed toward bodies depend on the nature and the quantity of matter of such bodies, as happens in the case of magnetic bodies. — Isaac Newton

Bullialdus wrote that all force respecting ye Sun as its center & depending on matter must be reciprocally in a duplicate ratio of ye distance from ye center. — Isaac Newton

The moon gravitates towards the earth and by the force of gravity is continually drawn off from a rectilinear motion and retained in its orbit. — Isaac Newton

A body in motion tends to stay in motion unless acted on by an outside force. — Isaac Newton

An object that is at rest will tend to remain at rest. An object that is in motion will tend to remain in motion unless acted upon by an outside force. — Isaac Newton

The alternation of motion is ever proportional to the motive force impressed; and is made in the direction of the right line in which that force is impressed. — Isaac Newton

Inherent force of matter is the power of resisting by which everybody, so far as it is able, perseveres in its state either of resting or of moving uniformly straight forward. — Isaac Newton

Centripetal force is the force by which bodies are drawn from all sides, are impelled, or in any way tend, toward some point as to a center. — Isaac Newton

An object in motion tends to remain in motion along a straight line unless acted upon by an outside force. — Isaac Newton

Every body persists in a state of rest or of uniform motion in a straight line, unless it is compelled to change that state by forces having impact upon it. — Isaac Newton

Truth is the offspring of silence and meditation. — Isaac Newton

Plato is my friend, Aristotle is my friend, but my greatest friend is truth. — Isaac Newton

Amicus Plato–amicus Aristoteles–magis amica veritas. (Plato is my friend–Aristotle is my friend–but my greatest friend is truth.) — Isaac Newton

Where both are friends, it is right to prefer truth. — Isaac Newton

To arrive at the simplest truth requires years of contemplation. — Isaac Newton

Truth is ever to be found in simplicity, and not in the multiplicity and confusion of things. — Isaac Newton

The great ocean of truth lay all undiscovered before me. — Isaac Newton

To myself I am only a child playing on the beach, while vast oceans of truth lie undiscovered before me. — Isaac Newton

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. — Isaac Newton

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. — Isaac Newton

I seem to have been lIke a chIld playIng on the sea shore, fIndIng now and then a prettIer shell than ordInary, whIlst the great ocean of truth lay undIscovered before me. — Isaac Newton

I was lIke a boy playIng on the sea–shore, and dIvertIng myself now and then fIndIng a smoother pebble or a prettIer shell than ordInary, whIlst the great ocean of truth lay all undIscovered before me. — Isaac Newton

For every action, there is an equal and opposite reaction. — Isaac Newton

And to every action there is always an equal and opposite or contrary, reaction. — Isaac Newton

To every action there is always opposed an equal reaction. — Isaac Newton

To any action there is always an opposite and equal reaction; in other words, the actions of two bodies upon each other are always equal and always opposite in direction. — Isaac Newton

Do not Bodies act upon Light at a distance, and by their action bend its Rays; and is not this action (caeteris paribus) [all else being equal] strongest at the least distance? — Isaac Newton

Impressed force is the action exerted on a body to change its state either of resting or of moving uniformly straight forward. — Isaac Newton

Gravity explains the motions of the planets, but it cannot explain who set the planets in motion. — Isaac Newton

I can calculate the motion of heavenly bodies but not the madness of people. — Isaac Newton

I can measure the motion of bodies but I cannot measure human folly. — Isaac Newton

His epitaph: Who, by vigor of mind almost divine, the motions and figures of the planets, the paths of comets, and the tides of the seas first demonstrated. — Isaac Newton

The motions which the planets now have could not spring from any natural cause alone, but were impressed by an intelligent Agent. — Isaac Newton

Pictures, propagated by motion along the fibers of the optic nerves in the brain, are the cause of vision. — Isaac Newton

I keep the subject of my InquIry constantly before me, and waIt tIll the fIrst dawnIng opens gradually, by lIttle and lIttle, Into a full and clear lIght. — Isaac Newton

Truth is the offspring of silence and meditation. I keep the subject constantly before me and wait ’til the first dawnings open slowly, by little and little, into a full and clear light. — Isaac Newton

The changing of Bodies into Light, and Light into Bodies, is very conformable to the Course of Nature, which seems delighted with Transmutations. — Isaac Newton

Atheism is so senseless. When I look at the solar system, I see the earth at the right distance from the sun to receive the proper amounts of heat and light. This did not happen by chance. — Isaac Newton

Are not rays of light very small bodies emitted from shining substances? — Isaac Newton

Is not Fire a Body heated so hot as to emit Light copiously? For what else is a red hot Iron than Fire? And what else is a burning Coal than red hot Wood? — Isaac Newton

My Design in this Book is not to explain the Properties of Light by Hypotheses, but to propose and prove them by Reason and Experiments: In order to which, I shall premise the following Definitions and Axioms. — Isaac Newton

We are to admit no more causes of natural things than such as are both true and sufficient to explain their appearances. — Isaac Newton

Therefore to the same natural effects we must, as far as possible, assign the same causes. — Isaac Newton

Therefore, the causes assigned to natural effects of the same kind must be, so far as possible, the same. — Isaac Newton

I do not think that this [the universe] can be explained only by natural causes, and are forced to impute to the wisdom and ingenuity of an intelligent. — Isaac Newton

Nature does nothing in vain when less will serve; for Nature is pleased with simplicity and affects not the pomp of superfluous causes. — Isaac Newton

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. — Isaac Newton