Why is any observer outside the artist required? Do you not use language to describe the world to yourself and help you understand it? Can you not do the same

Why is any observer outside the artist required? Do you not use language to describe the world to yourself and help you understand it? Can you not do the same thing with art? Edit: After more consideration, these sorts of means of internal communication might something like internal monologues or visualization and function quite differently for different people.