Are the themes from Breakfast of Champions postmodern? Why does the postmodern presentation of this book work so well?
There are many characteristics of postmodernism that appear in Vonnegut's Breakfast of Champions; metafiction, self-reflection, formal deconstruction, and existentialist philosophy are a handful of techniques that Vonnegut uses in his postmodernist novel.
In one example of this self-reflective metafiction, Vonnegut writes, "I sat there in the cocktail lounge of my own invention, and I stared through my leaks at a white cocktail waitress of my own invention. I named her Bonnie MacMahon” (199). In this passage, Vonnegut is acknowledging the fictitious nature of his novel, completely suspending the notion of realism in exchange for style and existential philosophy. By showing the reader that he, Vonnegut, is creating the novel, he is in a sense questioning the reality of human existence. Within the universe of the novel, Vonnegut is essentially an omnipotent God. He creates characters, watches over them, names them, and ultimately controls them. This metafictional commentary questions the existence of the author and the reader as well, bringing to light the possibility of free will being an illusion in favor of a divine power (or "writer") that decides the fate of all.
Postmodernism also often utilizes a deconstruction of traditional forms. In Breakfast of Champions, Vonnegut frequently uses ideas of self-reflection (that is, referring to the author himself as well as a number of his other works, characters, etc.), which is a common trait of postmodernism. Vonnegut tosses aside literary tradition in favor of a unique and often informal language that utilizes crude sketches to convey specific thoughts. Instead of explaining an object, Vonnegut often sketches one out on the page for the reader to see.
By abandoning traditional form, utilizing self-reflection, and opening the door to existentialist philosophy, Breakfast of Champions stands out as one of the most obvious forms of literary postmodernism.
Yes, several aspects of Vonnegut's Breakfast of Champions are postmodern.
For example, postmodern literature is much more self-referential than most earlier traditions of literature. That very much applies here. Vonnegut includes references to himself as the author of the book, and comments upon himself. He is not part of an objective reality, distinct from the book and prior to it. Instead, he is as much part of a creative reality as the other characters.
Both the style and the content of this novel are skeptical. Postmodern thinking and literature is deeply marked by skepticism. There is no such thing as an unquestioned master narrative in either the thought or the literature, and Vonnegut questions all stories and symbols of his culture.
Postmodern literature breaks the surface, commenting on itself as a created work of art. That's true both in the content of this novel and in the presentation. Look, for example, at the odd definitions of common words and the simple, even crude, drawings.
Thematically, the lack of free will and the way that people's actions are determined by biology are quite postmodern.