Sleep occurs in cycles, beginning with a descent into deep sleep and a return to near waking. One cycle generally lasts about 90 minutes, so if a person sleeps for eight hours, that person will likely sleep through five or six cycles. O n the rising side of the cycle, about 90 minutes into a night's sleep, the person experiences the first REM period and its accompanying dreams. We dream, in other words, not when we are deeply asleep but when we are close to awake. My son apparently awoke during one of his REM periods and became anxious about returning to his dream if he went back to sleep.
Some people claim they never dream.
Herein, however, is the problem. My son and I, however, want to know what dreams mean. Science too frequently answers our question why with an explanation how. The simplest and least mysterious theory of dreams suggests they are the psychic waste of the brain. All the images that bombarded the brain during the day are processed and disposed of in dreams.