Most mistakes in philosophy and logic occur because the human mind is apt to take the symbol for the reality.

Many of the things you can count, don't count. Many of the things you can't count, really count.

I used to go away for weeks in a state of confusion.

Live with purpose. Don't let people or things around you get you down.

In conclusion I wish to say that in working at the problem here dealt with I have had the loyal assistance of my friend and colleague M. Besso, and that I am indebted to him for several valuable suggestions.

Smoke like a chimney, work like a horse, eat without thinking, go for a walk only in really pleasant company.

The only mistake in life is the lesson not learned.