“All of us who possess life are composed of a singular structure: the cell. Some forty trillion cells, each obeying the command of a single sovereign—the brain—together perform the miracle we call life. But what were we before the cell existed, and how have we changed since?

I look here into the very substance of human existence, within the vast cycle of matter and mortality—atoms born in the stars, gathering into cells, and in time returning once more to nature.”

“Sky and earth, sea and living things, all converge into a single living body. What, then, is a living being within this biosphere—and how does it relate to the cosmos we inhabit?

This is the record of my first inquiry: as a neurosurgeon, I set out to lay bare everything I knew in answer to the most sweeping of questions—what is life?—drawing not only on medicine, but on physics, biology, and cosmology as well.”

“All of my scholarly reflection on life and the cosmos began, in truth, right here—in the clinic and the operating room, face to face with patients suffering in head and in pain.

Having performed more than 1,500 cranial operations, I believe that the precise record of a clinical career spent in direct contact with patients’ pain and their lives is itself the sturdiest root from which a patient-centered philosophy of medicine must grow.”