Isaac Newton

Gravity must be caused by some agent acting constantly according to certain laws; but whether this agent be material or immaterial, I have left to the consideration of my readers.

The particles of light are exceedingly small, and move with exceeding swiftness.

It seems probable to me, that God in the beginning formed matter in solid, massy, hard, impenetrable, moveable particles...

I have not been able to discover the cause of those properties of gravity from phenomena, and I frame no hypotheses.

He who thinks half-heartedly will not believe in God; but he who thinks seriously will believe in God, and will not doubt that God is the author of the world.

I shall not mingle conjectures with certainties.

The description of right lines and circles, upon which geometry is founded, belongs to mechanics. Geometry does not teach us to draw these lines, but requires them to be drawn.

The light which comes from the sun, and from all fire, consists of all the primary colours mixed together.

The cause of gravity is what I do not pretend to know.

It is possible that gravity may be essential to matter.

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

The wonderful arrangement and harmony of the cosmos could only have emerged from the plan of an omniscient and omnipotent Being.

I have studied these things – you have not.

The greatest challenges to the truth of the Holy Scriptures are not the work of infidels, but of professing Christians.

Nothing can be divided into fewer parts than it hath.

The power of gravity is of such a nature as to penetrate to the very centres of the sun and planets, without suffering the least diminution of its force.

It is not the business of philosophy to account for the truth of things by hypotheses, but to deduce them from phenomena.

The frame of nature, and the system of the world, we are to observe by the phenomena, and not to frame by imagination.

For the conservation of motion, it is necessary that the body should be moved in a vacuum.

To every action there is always opposed an equal reaction.