Levi Strauss was an anthropologist in the early 1900s who developed the theory of binary opposites. He believed that our understanding of words depends on understanding their opposites. Some common binary opposites in media include dark-light, good-evil, rational-irrational. Binary opposites are often used in films to help establish and reinforce the plot by creating a clear distinction between two opposing concepts or characters. However, critics argue that everything does not always have a clear opposite and there can be middle grounds between supposed binary concepts.