Generally speaking, a low flame means that this person may be born weak, or he has bad luck these days.
"It's hard for people with low flames to escape once they meet. It's best to swear." The meaning of this sentence is that people who are light or prone to "evil" in birthdates are hard to escape from taking off if they meet a drowning ghost, and swearing will scare the ghost away.
this is a superstitious saying: there are three fires on people, and ghosts and evil spirits dare not get close to them. On the top of the head and on the left and right shoulders. It is said that people can't see, and only ghosts can see at night. If someone calls you behind your back, when you turn around, the breath will blow out a fire on your shoulder. So the flame is low.
Another is that people who are light in birthdates (called bone fortune-telling index) are naturally low in flame. Such people are generally weak and sickly, and are easily referred to as "upper body" by ghosts and evil spirits.
Extended information:
In the book Exploration of Mysterious Phenomena: Revealing the Life in the Spiritual World, Miao Xingzhuang, the author, put forward a materialistic theistic system and thought that there really was a "spiritual world" in the world.
The so-called "ghost" is actually the soul that all kinds of living things continue to exist after leaving the body, and this spiritual body is also made of a certain substance, but we don't know much about this substance. Therefore, it is not idealism and superstition to admit that there is a "ghost". The author believes that there are several different ways of communication between the spiritual world and people, one of which is communication through hallucinations, so people who see ghosts actually don't really see ghosts with the naked eye, but an image formed through hallucinations. But this illusion is not produced out of thin air, but the result of spiritual body (ghost) stimulating the visual center of human brain.