Galileo Galilei

You cannot teach a man anything, you can only help him find it within himself.

I do not feel obliged to believe that the same God who has endowed us with sense, reason, and intellect has intended us to forgo their use.

See now the power of truth; the same experiment which at first glance seemed to show one thing, when more carefully examined, assures us of the contrary.

It is a beautiful and delightful sight to behold the body of the Moon.

(T)he increase of known truths stimulates the investigation, establishment, and growth of the arts.

I have been in my bed for five weeks, oppressed with weakness and other infirmities from which my age, seventy four years, permits me not to hope release. Added to this (proh dolor! [O misery!]) the sight of my right eye _ that eye whose labors (dare I say it) have had such glorious results _ is for ever lost. That of the left, which was and is imperfect, is rendered null by continual weeping.

Names and attributes must be accommodated to the essence of things, and not the essence to the names, since things come first and names afterwards.

Measure what can be measured, and make measurable what cannot be measured.

Philosophy [nature] is written in that great book which ever is 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 book is written in mathematical language, and the symbols are triangles, circles and other geometrical figures, without whose help it is impossible to comprehend a single word of it; without which one wanders in vain through a dark labyrinth.

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual.

The sun, with all those planets revolving around it and dependent on it, can still ripen a bunch of grapes as if it had nothing else in the universe to do.

I have never met a man so ignorant that I couldn't learn something from him.

Where the senses fail us, reason must step in.

If I were again beginning my studies, I would follow the advice of Plato and start with mathematics.

Facts which at first seem improbable will, even on scant explanation, drop the cloak which has hidden them and stand forth in naked and simple beauty.

All truths are easy to understand once they are discovered the point is to discover them.

The Bible shows the way to go to heaven, not the way the heavens go.

It vexes me when they would constrain science by the authority of the Scriptures, and yet do not consider themselves bound to answer reason and experiment.