Homer and Bart create their relationship and their roles within the contexts of their actions towards each other. If these roles were exterior and absolute, Homer should technically be the father, the speaker, and the generator, while Bart should correspondingly be the son, the writer, and the engendered. By Derrida's way of thinking, Bart's role is not merely a product of Homer's but also a resource and shaper in and of itself. Likewise, Homer's role often changes in response to Bart's actions. In thinking of fathers and sons, and speech and writing, Derrida claims that while written words descend from their spoken predecessors, speech also needs writing to be understood.
Writing can shape speech as well as vice versa.
Both are simulataneously fathers and sons, creators and byproducts. Bart cannot be the bad son without Homer, nor can Homer be a father without Bart. Their roles are intertwined, each containing parts of the other. For more on Derrida, click here .