The most difficult character in comedy is that of the fool, 

and he must be no simpleton that plays that part.

Thought is a kind of opium; 

it can intoxicate us, 

while still broad awake; 

it can make transparent the mountains 

and everything that exists.

The soul is so far from being a monad 

that we have not only to interpret other souls to ourself 

but to interpret ourself to ourself.

Though man a thinking being is defined, 

Few use the grand prerogative of mind. 

How few think justly of the thinking few! 

How many never think, who think they do!

Heresies are experiments in man's unsatisfied search for truth.

My yesterdays walk with me. 

They keep step, 

they are grey faces that peer over my shoulder.

The future is purchased by the present.

The intellect is always fooled by the heart.

To different minds, 

the same world is a hell, 

and a heaven.

Do not allow to slip away from you 

freedoms the people who came before you won 

with such hard knocks.

Life exists in the universe only because the carbon atom possesses certain exceptional properties.

Literature is the immortality of speech.

The poet speaks to all men 

of that other life of theirs 

that they have smothered and forgotten.

Creative activity could be described as a type of learning process 

where teacher and pupil are located in the same individual.

Ignorant men don't know what good they hold in their hands 

until they've flung it away.