Ten long trips around the sun since I last saw that smile, but only joy and thankfulness that on a tiny world in the vastness, for a couple of moments in the immensity of time, we were one.

For most of the history of our species we were helpless to understand how nature works. We took every storm, drought, illness and comet personally. We created myths and spirits in an attempt to explain the patterns of nature.

Contrary to the fantasies of the fundamentalists, there was no deathbed conversion, no last minute refuge taken in a comforting vision of a heaven or an afterlife. For Carl, what mattered most was what was true, not merely what would make us feel better. Even at this moment when anyone would be forgiven for turning away from the reality of our situation, Carl was unflinching. As we looked deeply into each other's eyes, it was with a shared conviction that our wondrous life together was ending forever.

It takes a fearless, unflinching love and deep humility to accept the universe as it is. The most effective way he knew to accomplish that, the most powerful tool at his disposal, was the scientific method, which over time winnows out deception. It can't give you absolute truth because science is a permanent revolution, always subject to revision, but it can give you successive approximations of reality.

If you are searching for sacred knowledge and not just a palliative for your fears, then you will train yourself to be a good skeptic.

I found that it was easiest to convey the information in the context of the life of the scientist or in the context of our own personal experience, and there was no idea that was too complicated that couldn't be explained clearly and directly.

Well, I actually grew up in the sixties. I feel very lucky, actually, that that was my slice of time that I was dealt. Let's remember that the real motivation in the sixties, and even in the fifties, was the Cold War.