Another very common use, in all cultures, of psychoactive substances is to give people transcendent experiences. To allow them to transcend their human and ego boundaries to feel greater contact with the supernatural, or with the spiritual, or with the divine, however they phrase it in their terms.

Dreaming is a phenomenon of purely individual consciousness, and consequently impossible to thoroughly deconstruct by a community of researchers. But dreaming matters.

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.

People who are contented and serene sleep well. They fall asleep easily, stay asleep, and wake refreshed. Conversely, people who are anxious, stressed, or depressed do not sleep well, and chronic insomnia is strongly associated with mood disorders. These are clear correlations, but what is cause and what is effect is not clear. Most experts agree that sleep and mood are closely related, that healthy sleep can enhance emotional well-being, while insufficient quantity or quality of sleep can adversely affect it.

Many exercise forms - aerobic, yoga, weights, walking and more - have been shown to benefit mood.

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.

You can't afford to get sick, and you can't depend on the present health care system to keep you well. It's up to you to protect and maintain your body's innate capacity for health and healing by making the right choices in how you live.