B) What is the relationship between the theory of intertextuality and the theory of archetypes?
a) Eco begins by analysing the core of the film, the script. He mentions a conversation between two characters in which one wants to tell the other a story, but stresses that she does not know the ending yet. This is exactly how the script was written - being completed during the process of making the film, instead of having been finished before. This marks the intertextual relationship between Casablanca and its own script.
Later, the author mentions another character ordering drinks. Interestingly, Laszlo orders a different drink every time. Plot-wise the action does not make much sense, nor is relevant to the story. Eco assumes that the script writer was simply copying such situations from various other films.
Finally, Casablanca can also be compared to Hamlet. Not because of the plot, but because of how both of them were written. Citing T.S. Eliot, Eco suggests that Casablanca and Hamlet were not the best works of their authors due to numerous different ways their authors meant for the plot to develop and form; eventually, both of them might feel improvised and rushed to the viewer/reader.
b) The theory of intertextuality refers to the relationship between different texts, how they shape and influence one another (for example, a motif from one work can appear, usually in slightly changed form, in another, because of a deliberate effort of the author who is familiar with the former). The theory of archetypes describes a part of the plot - a situation, a dialogue, a character, among others - that has been pre-established and is frequently reused in different texts, in order to provoke a certain reaction in the reader. It does not need to be universal, but rather relevant to a certain genre or society. Therefore, both theories are similar due to the existence of a part of the plot that has not been the original idea of the author, but appeared in the work as a result of them being familiar with particular notions - whether coming from a given text or being an already established idea.