Fight Club Film Theory: Tyler Durden Isn't The Only Character Who Doesn't Exist

5. Marla As Jack's Spirit Animal

As for what it all means thematically? Marla is depicted as a sickness-of-sorts in the early stages of the film, referred to as a wound that Jack can't stop tonguing, and when he imagines himself screaming at her, "I need this, now get out!", he's not talking about the physical meeting space - he's talking about his mind.

However, over the course of the film Marla's true function, to balance out Tyler and present an alternate future for Jack, becomes clear.

That she appears in his dream in place of the penguin, his power animal - or his spirit animal as we say nowadays - speaks volumes to the role she ends up playing in Jack's story.

There will be those fans who insist that the theory is in of itself a giant plot hole, and that Marla must exist because a waiter takes her order late in the film.

But it's important to remember that a) we're not seeing a reliable version of events and b) it's made abundantly clear that Project Mayhem's followers gladly humour their leader's evident madness.

The subjective nature of the narrative means that these moments pointing to Marla's concrete existence don't really matter, and to cling to them is to totally miss the point - everything is up for questioning and doubt in Fincher's film, and that's exactly the way he wants it.

But there is one piece of extremely compelling "evidence" that surely stands above the rest...