It is idle to dispute with old men. Their opinions, like their cranial sutures, are ossified.

Nothing inspires more reverence and awe in me than an old man who knows how to change his mind.

As long as our brain is a mystery, the universe, the reflection of the structure of the brain will also be a mystery.

Unfortunately, nature seems unaware of our intellectual need for convenience and unity, and very often takes delight in complication and diversity.

It is notorious that the desire to live increases as life itself shortens.

Intellectual work is an act of creation. It is as if the mental image that is studied over a period of time were to sprout appendages like an ameba—outgrowths that extend in all directions while avoiding one obstacle after another—before interdigitating with related ideas.

Every man if he so desires becomes sculptor of his own brain.