Phase 1: It begins as a literal/ surface/ simplistic understanding, where the meaning of an idea, etc is understood literally, eg. a statement or an instruction.It is similar to a child viewing a photograph of the ocean. He simply understands that it is the ocean that he is perceiving. He also understands that it is beautiful and serene when told by his mother.
In short, it is simple because the meaning of an idea, etc. is understood literally.
Phase 2: It proceeds into complication where the idea is challenged and scrutinized in order to achieve in-depth understanding. As the child grows up, he starts to question why the ocean is being perceived as beautiful and serene by his mother when smaller fishes are being preys to the bigger ones. He finds that nothing is beautiful and serene as living things are attacking and consuming each other up every single moment.
In short, it is complicated as the existing idea is causing confusion with the mind's expectations.
In short, it returns to the simple state of understanding as all the conflicts are resolved.