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.

Among other things, neuroplasticity means that emotions such as happiness and compassion can be cultivated in much the same way that a person can learn through repetition to play golf and basketball or master a musical instrument, and that such practice changes the activity and physical aspects of specific brain areas.

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.

Practicing regular, mindful breathing can be calming and energizing and can even help with stress-related health problems ranging from panic attacks to digestive disorders.

The bottom line is that the human body is complex and subtle, and oversimplifying - as common sense sometimes impels us to do - can be hazardous to your health.

Everyone prefers some foods over others, but some adults take this tendency to an extreme. These people tend to prefer the kinds of bland food they may have enjoyed as children - such as plain or buttered pasta, macaroni and cheese, cheese pizza, French fries and grilled cheese sandwiches - and to restrict their eating to just a few dishes.

If we can make the correct diagnosis, the healing can begin. If we can't, both our personal health and our economy are doomed.