Galileo Galilei

To make a discovery is to see what everyone else has seen, and to think what no one else has thought.

Where the senses fail us, reason must step in.

The universe is an immense, an infinite, and an eternal machine.

It is not in the power of any created being to make a new substance, or to destroy an old one.

The motion of the earth is a fact, and it is as certain as that the sun rises in the east and sets in the west.

I have loved the stars too fondly to be fearful of the night.

Nature does not care whether her reasons and ways of operating are understandable to man.

The senses, assisted by reason, are the only true guides to the knowledge of nature.

The laws of nature are written in the language of mathematics.

The universe is a machine, and its laws are mathematical.

It is a great pity that we are so often led astray by the authority of others.

The more I study, the more I am convinced that the world is governed by immutable laws.

The purpose of science is to discover the laws of nature.

The truth is always simple.

I have discovered in the heavens many things that have not been seen before.

The senses, though they may deceive us, are the only source of knowledge.

The universe is a vast and wonderful machine, and it is our duty to understand it.

The study of nature is the study of God.

I think that in the discussion of natural problems, we ought to begin not with the Scriptures, but with experiments and demonstrations.

Yet it is not to be denied that the motion of the earth, which I shall now propose to you, is a thing most difficult to conceive, and perhaps even more difficult to believe.