Isaac Newton

As a blind man has no idea of colours, so have we no idea of the manner by which the all-wise God perceives and understands all things.

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.

A centripetal force is that by which bodies are drawn or impelled, or any way tend, towards a point as to a centre.

That it should be so is very reasonable, Nature being ever conformable to her self; but an experimental Proof is desired.

I do not define time, space, place and motion, as being well known to all.

So that 'tis a wonder, that Telescopes represent Objects so distinct as they do.

It may be, that there is no such thing as an equable motion, whereby time may be accurately measured.

The only Remedy is a most serene and quiet Air, such as may perhaps be found on the tops of the highest Mountains above the grosser Clouds.

For times and spaces are, as it were, the places as well of themselves as of all other things.

The Colours of Bubbles with which Children play are various, and change their Situation variously, without any respect to any Confine or Shadow.

To every action there is always opposed an equal reaction: or the mutual actions of two bodies upon each other are always equal, and directed to contrary parts.

I never yet found any Body, which by reflecting homogeneal Light could sensibly change its Colour.

For a body going on with a continued motion can never pass out of one hyperbola into its conjugate hyperbola.

For the Rays to speak properly are not coloured. In them there is nothing else than a certain Power and Disposition to stir up a Sensation of this or that Colour.

I have hitherto been treating of the attractions of bodies towards an immovable centre; though very probably there is no such thing existent in nature.

Of the Light which now by the Mixture of all the Colours appeared white, there was no Part really white.

Finite particles are not moments, but the very quantities generated by the moments.

For whiteness is a mean between all Colours, having it self indifferently to them all, so as with equal facility to be tinged with any of them.

To this purpose the philosophers say that Nature does nothing in vain, and more is in vain when less will serve; for Nature is pleased with simplicity, and affects not the pomp of superfluous causes.

And it was very pleasant to see them gradually swell or contract accordingly as the Colour of the Light was changed.