I am seeking assistance in deciding upon a good thesis statement for a 1,300-word essay I need to write on the novel Fight Club by Chuck Palahniuk for a literature class. I need to use one of the following criticisms in my essay: Marxism Gender Theory/Masculinity Phenomenology Psychoanalytic Theory (confined to Freud, Jung, or Lacan) Poststructuralism/Postmodernism I've read the book and I know that: Project Mayhem's actions would fit with the Marxism criticism; The fact that the narrator and Tyler are the same person would work with the Psychoanalytic criticism (id, ego, superego); The narrator's dissatisfaction with his own masculinity and his desire to redefine it through Fight Club might work with the Gender Theory/Masculinity criticism. My problem is that I need assistance figuring out which would work best for a thesis statement and how to build upon it with supporting evidence from the book.

While any of your possible thesis topics could make for a great essay, gender theory and the idea of masculinity as a construct would likely prove easiest to argue with Palahniuk's narrative. Psychoanalytic theory and Marxist ideology could be lenses through which we view Fight Club, but the question of what it means to be a man at the end of the twentieth century is what the novel is truly about.
Palahniuk has been quoted as saying:

bookstores were full of books like The Joy Luck Club and The Divine Secrets of the Ya-Ya Sisterhood and How to Make an American Quilt. These were all novels that presented a social model for women to be together. But there was no novel that presented a new social model for men to share their lives.

Essentially, Chuck Palahniuk raises the question of modern man's search for his place in the world. He writes in the book, "We are God's middle children" (141). The argument is being made that there is nothing unique or noteworthy about modern man or the modern notion of masculinity. Man has been forgotten and abandoned. The search for identity, and reestablishing that identity, is what Fight Club is about. Therefore, while the other theses could make for an interesting and singular thesis; they are just pieces used to find and establish masculine identity in the novel.

Personally, I think psychoanalysis would be a great topic to discuss in this essay because of the clear psychological intrigue in the novel and the film. The dual personality can, in fact, be related to human nature and Freudian themes. I believe a good thesis statement for the novel would be:

The dual personality exhibited by Durden and the narrator is an example of the duality of man, which shows an individual in his struggle to maintain civility against his primal self: the id.

This essay could tackle all the ways in which the narrator attempts to improve himself and control his subconscious desires while Durden acts entirely on impulse, essentially acting as the opposing superego and id. Additionally, you could discuss the narrator's relationships and how they develop differently under the control of each personality—both positively and negatively.

Gender theory and masculinity would be the best topic to choose for Chuck Palahniuk's novel Fight Club. The issue with choosing Marxist criticism or psychoanalytic theory is that both are limited in scope throughout the book. In other words, they are elements in the narrative—e.g., Project Mayhem as a parody of Marxist revolutionary ideals, or the id versus ego mechanisms that contributed to multiple personality disorder—but neither one is the overarching theme.
In essence, Fight Club is about the modern man trying to find meaning in his life. Early in the story, Palahniuk makes a reference to the concept of male insecurity and concepts of emasculation when the protagonist goes to a testicular cancer support group. The loss of one's ability to naturally produce testosterone, and the testicles themselves, which physically and symbolically represent manhood, is the author's hint at the masculinity-emasculation subtext throughout the novel.
Even the philosophical origins of the fight club—which eventually evolves into the terrorist cult group Project Mayhem—are born out of beta male frustrations. The members of the fight club unleash their primal violence to express what they believe is their oppressed masculinity.
Tyler Durden states that urban postmodern culture—e.g., consumerism, the glorification of beautiful celebrities and models, corporate culture, et al.—suppresses the modern man's natural instincts in the same way a domesticated dog no longer resembles its ancient wolf ancestors.
Likewise, the protagonist's split personality is born out of necessity, or as a defense mechanism. Tyler is constructed by the protagonist's subconsciousness because the protagonist lacks the aggression or initiative that Tyler possesses. The protagonist feels inadequate as a beta male and wants to possess alpha male qualities, and thus Tyler is created.
Since the theme of masculinity and the protagonist's struggle with it is present in every element or subplot of the novel, it would make a good thesis subject.