There is frequently more to be learned 

from the unexpected questions of a child 

than the discourses of men.

I have always imagined that Paradise will be a kind of library.

There is much to be said for failure. 

It is much more interesting than success.

I have fun with ideas; 

I play with them.

Fear is our deepest and strongest emotion, 

and the one which best lends itself 

to the creation of nature-defying illusions.

Let your tongue speak what your heart thinks.

The thing that I fear discriminating against is humour and truth.

Idealism increases in direct proportion to one's distance from the problem.

All deception 

in the course of life 

is indeed nothing else 

but a lie reduced to practice, 

and falsehood passing from words into things.

I cannot summon up inspiration; 

I myself am summoned.

My own way of thinking 

is to ponder long 

and I hope deeply 

on problems 

and for a long time 

which I keep away for years and years 

and I never really let them go.

Knowledge comes, 

but wisdom lingers.

The great instrument of moral good is the imagination.

The brightest flashes in the world of thought are incomplete 

until they have been proven to have their counterparts in the world of fact.

Truth is in things, 

and not in words.

The poetical language of an age should be the current language heightened.