Principle of dream interpretation: "daydreaming, dreaming at night" follows the conservation of matter in the material world. We cannot create something out of nothing, and so does consciousness. The content of consciousness has a source. Think about the huge subconscious mind. Dreams are products based on people's existing consciousness.
Dream interpretation is now a science. It adopts the principle of psychodynamics, emphasizes the social and cultural background of dreams and the relationship between dreams and reality, and helps people to deal with and solve inner contradictions and conflicts.