The best thinking has been done in solitude. The worst has been done in turmoil.

The man who doesn't make up his mind to cultivate the habit of thinking misses the greatest pleasure in life.

There is no limit to which a man will not go to avoid thinking.

The trouble with most people is that they quit before they start.

There is nothing either good or bad but thinking makes it so.

When the sufferers learn to think, then the thinkers will learn to suffer.