But that's the point, isn't it? A dialogue like this hinges on a few assumptions about the characters involved, including the contradictory position that the author expects from the audience: that we will treat these characters as both facsimiles and accurate representations of the philosophies under discussion.

Yet it all falls apart when we go "Why wouldn't the Utilitarian simply respond to the Deontologist with 'I don't believe you?'" There's no point in continuing this conversation past that realization.