Technology has a shadow side. It accounts for real progress in medicine, but has also hurt it in many ways, making it more impersonal, expensive and dangerous. The false belief that a safety net of sophisticated drugs and machines stretches below us, permitting risky or lazy lifestyle choices, has undermined our spirit of self-reliance.

In Europe, when tobacco was first introduced, it was immediately banned. In Turkey, if you got caught with tobacco, you had your nose slit. China and Russia imposed the death penalty for possession of tobacco.

Each day as I travel through downtown Tucson, I am amazed at how quickly the most ancient of human behaviors have changed. For as long as there have been Homo sapiens - roughly 200,000 years - people have filled their lives principally with two activities: talking directly with other people, and doing physical things.

My passion for gardening may strike some as selfish, or merely an act of resignation in the face of overwhelming problems that beset the world. It is neither. I have found that each garden is just what Voltaire proposed in Candide: a microcosm of a just and beautiful society.

Human beings have survived for millennia because most of us make good decisions about our health most of the time.

It does kids no favors, and sets them up for a potential lifetime of poor health and social embarrassment, to excuse them from family meals of real food. Everyone benefits from healthy eating, but it is particularly crucial at the beginning of life.

The notion that a human being should be constantly happy is a uniquely modern, uniquely American, uniquely destructive idea.