God is known by nature in his works, and by doctrine in his revealed word.
Science proceeds more by what it has learned to ignore than what it takes into account.
Infinities and indivisibles transcend our finite understanding, the former on account of their magnitude, the latter because of their smallness; Imagine what they are when combined.
Measure what is measurable, and make measurable what is not so.
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual.
The book of nature is written in the language of mathematics.
There are those who reason well, but they are greatly outnumbered by those who reason badly.
Wine is sunlight, held together by water.
Nothing occurs contrary to nature except the impossible, and that never occurs.
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.
I abjure with a sincere heart and unfeigned faith, I curse and detest the said errors and heresies, and generally all and every error and sect contrary to the Holy Catholic Church.
The Milky Way is nothing else but a mass of innumerable stars planted together in clusters.
The hypothesis is pretty; its only fault is that it is neither demonstrated nor demonstrable. Who does not see that this is purely arbitrary fiction that puts nothingness as existing and proposes nothing more than simple noncontradiciton?
You may force me to say what you wish; you may revile me for saying what I do. But it moves.
But some, besides allegiance to their original error, possess I know not what fanciful interest in remaining hostile not so much toward the things in question as toward their discoverer.
The earth, in fair and grateful exchange, pays back to the moon an illumination similar to that which it receives from her throughout nearly all the darkest gloom of the night.
Showing a greater fondness for their own opinions than for truth, they sought to deny and disprove the new things which, if they had cared to look for themselves, their own senses would have demonstrated to them.
Some, merely to contradict what I had said, did not scruple to cast doubt upon things they had seen with their own eyes again and again.
With regard to matters requiring thought: the less people know and understand about them, the more positively they attempt to argue concerning them.
See now the power of truth.