What is the purpose of Antithesis?

The point of an antithesis is to shock the audience with two different ideas. By pairing them together it forces the reader to pay attention. It is a bold statement that just screams "think about me!" Honestly the purpose depends on the piece. It can also be used to create rythym in a piece of literary work. That rythym can lead to a clymatic effect. But in the end it changes from each peice of literary work. So... yeah :D