Freud was a psychological determinist. He believes that there is a strict causal relationship between people's psychological activities. Nothing is accidental and dreams are no exception. It is not an accidental association, but the realization of a wish.
During sleep, the inspection of superego is lax, and the subconscious desire bypasses the resistance, taking the opportunity to break into consciousness in disguise and form a dream. It can be seen that dreams are euphemisms for the desire to suppress the subconscious when you are awake.
Dreams are the secret passage to the subconscious. Through the analysis of dreams, we can see people's inner psychology and explore people's subconscious desires and conflicts.
Social and cultural theory
Freud believed that in primitive society, people were weak, and in order to resist the invasion of nature and the threat of other creatures, people could only live in groups. The instinctive satisfaction between people is contradictory. Therefore, in order to live in the same place, people need to conclude contracts and restrict each other. "Civilization only refers to the sum of the results and systems produced by human defense against nature and the adjustment or accumulation of interpersonal relationships."
In addition, Freud explained totem worship with his Oedipus complex.