If I have seen further than others, it is by standing upon the shoulders of giants.

There is one thing stronger than all the armies in the world; and that is an idea whose time has come.

The change in motion is proportional to the motive force impressed; and is made in the direction of the right line in which that force is impressed.

Plato is my friend; Aristotle is my friend, but my greatest friend is truth.

Every body continues in its state of rest, or of uniform motion in a right line, unless it is compelled to change that state by forces impressed upon it.

I frame no hypotheses; for whatever is not deduced from the phenomena is to be called an hypothesis; and hypotheses, whether metaphysical or physical, whether of occult qualities or mechanical, have no place in experimental philosophy.

I do not know what I may appear to the world; but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.

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.

A man may imagine things that are false, but he can only understand things that are true.

If I have ever made any valuable discoveries, it has been owning more to patient attention, than to any other talent.