Must a dream be a dream ~?

Dream is a subjective experience, an imaginary image, sound, thinking or feeling produced by people during sleep, which is usually involuntary. The scientific discipline of studying dreams is called the study of dreams. Dreaming is related to REM sleep, which is a shallow sleep state in the later stage of sleep. It is characterized by rapid eye movement, pontine stimulation, accelerated breathing and heartbeat, and temporary limb paralysis. Other sleep periods may also dream, but rarely. Lack of sleep when entering deep sleep is considered to be related to dreaming. Dream is an image language. These images range from ordinary things to surreal things; In fact, dreams often inspire artistic and other inspirations. The forms of dreams include unpleasant nightmares and spring dreams that may accompany wet dream. Most scientists believe that all human beings dream and sleep at the same frequency every time. Therefore, if a person feels that he has never dreamed or only had one dream in one night, it is because his memory of those dreams has disappeared. This kind of "memory erasure" usually occurs when a person naturally and gently enters the slow-wave sleep stage from the rapid eye movement sleep stage and enters the awake state. If a person is awakened directly from REM sleep (for example, by an alarm clock), they are more likely to remember the dreams they had during REM sleep (but not all the dreams that happened during REM sleep will be remembered, because a slow-wave sleep period will be inserted between each active sleep, which will lead to the memory of the previous dream disappearing). True dreaming has been directly confirmed only in humans, but many people think that dreaming may also happen to other animals. Animals have been proved to have REM sleep, but their subjective experience is difficult to determine. The animal with the longest average REM sleep time is pangolin. Mammals may be the only dreamers in nature, or at least the most frequent dreamers, because it is related to their sleep patterns. Some people think that the above explanation of dreams is unscientific. Dreams are just a kind of psychological activity when people are sleeping. The psychological activity in dreams, like the psychological activity when people are awake, is a reflection of objective things in the human brain. The bizarre dream in the dream is the illusion of stimulating various objective things when people are unconscious during sleep. For example, when people are awake and tachycardia, it seems that the palpitation feeling of being chased becomes a bizarre nightmare of being chased, and when people are awake and bradycardia or premature, the palpitation feeling becomes a bizarre nightmare of being hung and falling. In dreams, we often feel slight physiological symptoms that some people can't easily feel when they are awake, which is caused by the fact that the stimulation of external objective things is relatively small, while the stimulation of internal objective things is relatively strong. Dream Cause Dream Cause-Dreams are inextricably linked with people's social environment, psychological factors and physical condition. Qian Zhongshu emphasized and elaborated China's ancient dream interpretation theory in Liezi Zhang Zhan's Notes on Zhou Muwang, and put forward the relationship between dream formation and "thinking" or formation and "cause". Dreaming, the so-called "body-qi dream", becomes a dream because the feelings in the body are touched.