“In the sciences, the authority of thousands of opinions is not worth as much as one tiny spark of reason in an individual man.”

Being infinitely amazed, so do I give thanks to God, Who has been pleased to make me the first observer of marvelous things, unrevealed to bygone ages.

The increase of known truths stimulates the investigation, establishment, and growth of the arts.

Where the senses fail us, reason must step in.

The vain presumption of understanding everything can have no other basis than never having understood anything.

You may force me to say what you wish; you may revile me for saying what I do. But it moves.

See now the power of truth.

In my studies of astronomy and philosophy I hold this opinion about the universe, that the Sun remains fixed in the centre of the circle of heavenly bodies, without changing its place; and the Earth, turning upon itself, moves round the Sun.

Who would dare assert that we know all there is to be known?

It is surely harmful to souls to make it a heresy to believe what is proved.

Knowing thyself, that is the greatest wisdom.

Philosophy is written in that great book which ever lies before our eyes. I mean the universe, but we cannot understand it if we do not first learn the language and grasp the symbols, in which it is written.

The nature of the human mind is such that unless it is stimulated by images of things acting upon it from without, all remembrance of them passes easily away.

We cannot teach people anything; we can only help them discover it within themselves.

Holy Scripture could never lie or err…its decrees are of absolute and inviolable truth.

Holy Scripture could never lie or err…its decrees are of absolute and inviolable truth.

Nature is written in mathematical language.