The man who never reads will never be read; he who never quotes will never be quoted. He who will not use the thoughts of other men’s brains, proves that he has no brains of his own.

A man who does not think for himself does not think at all.

If a man's at odds to know his own mind it's because he hasn't got aught but his mind to know it with.

Intellect is invisible to the man who has none.

The man who does not do his own thinking is a slave, and is a traitor to himself and to his fellowmen.

All the intelligence in the world is useless to the one who has none.

I am afraid I shall never have any brains, after all!

A man who has the knowledge but lacks the power clearly to express it is no better off than if he never had any ideas at all.

He who is not master of his own thoughts is not accountable for his own deeds.

I cannot trust a man to control others who cannot control himself.

Fear has no brains; it is an idiot.

Any man under 30 who is not a liberal has no heart, and any man over thirty who is not a conservative has no brains.

Men simply don’t think.” And

We can be knowledgeable with other men’s knowledge, but we can’t be wise with other men’s wisdom.