I think, therefore I am.

Property is surely a right of mankind as real as liberty.

Muddy water is best cleared by leaving it alone.

The path to success is to take massive, determined action.

Yesterday I was clever, so I wanted to change the world. Today I am wise, so I am changing myself.

The weak can never forgive. Forgiveness is the attribute of the strong.

The greatest pride, or the greatest despondency, is the greatest ignorance of one's self.

To kill an error is as good a service as, and sometimes even better than, the establishing of a new truth or fact

There are four ways, and only four ways, in which we have contact with the world. We are evaluated and classified by these four contacts: what we do, how we look, what we say, and how we say it.

Thoughts without content are empty, intuitions without concepts are blind.

I am a lover of truth, a worshipper of freedom, a celebrant at the altar of language and purity and tolerance.

Where you stand depends on where you sit.

Wrong life cannot be lived rightly.

Nature is pleased with simplicity. And nature is no dummy

Don't take tomorrow to bed with you.

Where wisdom reigns, there is no conflict between thinking and feeling.

If you have no problems, then you have no clue to what is going.

He that cannot reason is a fool. He that will not is a bigot. He that dare not is a slave.

Tomorrow hopes we have learned something from yesterday.

Everybody is ignorant, only on different subjects.

Learned we may be with another man's learning: we can only be wise with wisdom of our own.