Astronomers are pure of heart and appealingly puerile. They look into the midnight sky and ask big questions, just as we did when we were in college: Who are we? Where do we come from? And why are we standing around outside on the night before finals, do we want to end up making elevator parts for a living like our father or what?

The surest and most insidious enemy of freedom is not dictatorship, but complacency.

Whatever else I might have thought of [President George W] Bush's call, with its assumption that prayer is some sort of miracle Vicks VapoRub for the national charley horse, it's clear that his hands were reaching for any hands but mine.

Nature is a tenacious recycler, every dung heap and fallen redwood tree a bustling community of saprophytes wresting life from the dead and discarded, as though intuitively aware that there is nothing new under the sun. Throughout the physical world, from the cosmic to the subatomic, the same refrain resounds. Conservation: it's not just a good idea, it's the law.

What is wrong with looking muscular? Muscles are beautiful. Strength is beautiful. Muscle tissue is beautiful. It is metabolically, medically, and philosophically beautiful. Muscles retreat when they're not used, but they will always come back if you give them good reason. No matter how old you get, your muscles never lose hope. Few cells of the body are as capable as muscle cells are of change and reformation, of achievement and transcendence.

evolution is a tinkerer, an ad-hocker, and a jury-rigger. It works with what it has on hand, not with what it has in mind. Some of its inventions prove elegant, while in others you can see the seams and dried glue.

[On women:] We are all yeses. We are worthy enough, we passed inspection, we survived the great fetal oocyte extinctions. In that sense, at least - call it a mechanospiritual sense - we are meant to be. We are good eggs, every one of us.