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

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.

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

The Great Man... is colder, harder, less hesitating, and without fear of 'opinion'; he lacks the virtues that accompany respect and 'respectability,' and altogether everything that is the 'virtue of the herd.' If he cannot lead, he goes alone... He knows he is incommunicable: he finds it tasteless to be familiar... When not speaking to himself, he wears a mask. There is a solitude within him that is inaccessible to praise or blame.

Thinking is the hardest work there is, which is probably the reason so few engage in it.