“Nothing occurs contrary to nature except the impossible, and that never occurs.”

The greatest wisdom is to get to know oneself.

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

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

Mathematics is the key and door to the sciences.

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.

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

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

The deeper I go in considering the vanities of popular reasoning, the lighter and more foolish I find them.

Passion is the genesis of genius.

Earth, turning upon itself, moves round the Sun.

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

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

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

Two truths cannot contradict one another.

I am certainly interested in a tribunal in which, for having used my reason, I was deemed little less than a heretic.

In time you may discover everything that can be discovered, and still your progress will only be progress away from humanity.

Imagination grows by exercise, and contrary to common belief, is more powerful in the mature than in the young.

To accuse another of having weak kidneys, lungs, or heart, is not a crime; on the contrary, saying he has a weak brain is a crime.

See, even despite pious statements to the contrary, much of the industrialized world has not yet come to terms with the recognition of the fallacy of what I call the strong man syndrome.

The last 15 years, there has been no recorded warming. Contrary to all the theories that they are expounding, there should have been warming over the last 15 years. It hasn’t happened.

But the nature of the universe is such that ends can never justify means. On the contrary, the means always determine the end.

A child-like man is not a man whose development has been arrested; on the contrary, he is a man who has given himself a chance of continuing to develop long after most adults have muffled themselves in the cocoon of middle-aged habit and convention.

Do we ever get what we really want? Do we ever achieve what our powers have ostensibly equipped us for? No: everything works by contraries.

What is earnest is not always true; on the contrary, error is often more earnest than truth.