But, because my private lectures and domestic pupils are a great hinderance and intteruption of my studies, I wish to live entirely exempt from the former, and in great measure from the latter. ... in short, I should wish to gain my bread from my writings.

Nonetheless, it moves.

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.

Where the senses fail us, reason must step in.

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

It was granted to me alone to discover all the new phenomena in the sky and nothing to anybody else. This is the truth which neither envy nor malice can supress.

Nature . . . is inexorable and immutable; she never transgresses the laws imposed upon her, nor cares a whit whether her abstruse reasons and methods of operations are understandable to men.