To command their professors of astronomy to refute their own observations is to command them not to see what they do see and not to understand what they do understand.

Nature is written in mathematical language.

Nature...does not act by means of many things when it can do so by means of a few.

I am certainly interested in a tribunal in which, for having used my reason, I was deemed little less than a heretic. Who knows but men will reduce me from the profession of a philosopher to that of historian of the Inquisition!

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.

It is necessary for the Bible, in order to be accommodated to the understanding of every man, to speak many things which appear to differ from the absolute truth so far as the bare meaning of the words is concerned.

To excite in us tastes, odors, and sounds I believe that nothing is required in external bodies except shapes, numbers, and slow or rapid movements. ... if ears, tongues, and noses were removed, shapes and numbers and motions would remain, but not odors or tastes or sounds.