Change is essential and practically unavoidable, mandated both by the constraints of time and medium, but how much is always a balance. Some film theorists have argued that a director should be entirely unconcerned with the source, as a novel is a novel and a film is a film, and the two works of art must be seen as separate entities. Since a transcription of a novel into film is impossible, even holding up a goal of "accuracy" is absurd. Others argue that what a film adaptation does is change to fit (literally, adapt), and the film must be accurate to the effect (aesthetics), the theme, or the message of a novel and that the filmmaker must introduce changes, if necessary, to fit the demands of time and to maximize faithfulness along one of those axes.