I'll walk where my own nature would be leading: 

It vexes me to choose another guide.

Beauty is a relation, 

and the apprehension of it 

a comparison.

We participate in a tragedy; 

at a comedy we only look.

One thing that being a scientist has taught me is 

that you can never be certain about anything. 

You never know the truth. 

You can only approach it 

and hope to get a bit nearer to it each time. 

You iterate towards the truth. 

You don't know it.

It is necessary to have wished for death 

in order to know how good it is to live.

Books have led some to learning 

and others to madness.

Better make the horizon your goal; 

it will always be ahead of you.

Invention, 

strictly speaking, 

is little more than a new combination of those images 

which have been previously gathered and deposited in the memory; 

nothing can come of nothing.

In reality, 

both religion and science are expressions of man's uncertainty. 

Perhaps the paradox is that certainty, 

whether it be in science or religion, 

is dangerous.

Only that day dawns to which we are awake.

Our intonations contain our philosophy of life, 

what each of us is constantly telling himself about things.

By the work 

one knows the workman.

Calm mind brings inner strength and self-confidence, 

so that's very important for good health.

Sunlight is painting. 

Moonlight is sculpture.

Every exit is an entry somewhere else.

Simplicity is the most difficult thing to secure in this world; 

it is the last limit of experience 

and the last effort of genius.