Marla and Tyler Dress Alike

One of the first clues that Marla is not real is her likeness to Tyler. Fincher offers us clever, subtle hints that Tyler and Marla are the same person as Jack. One of the most obvious signs are the clothing that Marla and Tyler wear.

Tyler's hair is styled and worn almost identical to Marla's throughout most of the film. Marla and Tyler are both seen wearing a similar faux fur coat, wearing sunglasses, almost identical rings and they are seen smoking in virtually every scene in the film.

Even the framing of the shots is nearly identical when they are shown wearing similar clothes as well as the same facial expressions.

Marla and Jack (Edward Norton) Dress Alike

This is even more telling than Marla's likeness to Tyler, but slightly more symbolic.

Jack (the narrator, played by Edward Norton) is seen gradually looking more like Marla up until the final scene where we see the silhouettes of the two standing together, holding hands.

From the back, it is virtually impossible to tell who is who.

Note how Jack's long coat and lack of pants have made it seem as if he is wearing a dress, a near perfect mirror image of Marla as they watch the 12 skyscrapers be demolished.

Marla Has No Reflection, Neither Does Tyler

Marla and Tyler do not have reflections, because they do not exist.

Unless Jack is with Marla (or Tyler) their reflection or image will not appear. This is because this is the only time Marla is "real" to the narrator.

We can see a great example of this in the scene when Tyler is saving Marla from suicide and goes to her hotel to save her. On their way down the hallway they walk directly by a convex mirror.

When they both walk by, neither of them has a reflection. The mirror is facing the camera and should show the reflection of the two walking by, but the only reflections we see are of the paramedics running past Marla and Tyler in the same exact spot where they had been walking.

We know for a fact that Jack's imagined alternate personalities have no objective "image" in the real world. This is clearly the case in the final scene of the movie where Jack is fighting Tyler in the parking garage.

The film cuts to the security cameras in the parking garage (which Jack never saw, just like he never saw the scene where Tyler saves Marla) and we can see that Tyler is not visible, since he does not exist.

The reason we see that Tyler and Marla have reflections in other scenes (e.g. when Jack is checking Marla for breast cancer or when Tyler is looking in the bathroom mirror) is because at those points Jack was acting his himself observing the alternate personality as a separate person.

In the scene where Tyler goes to save Marla, Jack is supposedly not there, meaning Tyler and Marla are not actually being observed (except by us). We are being told to "imagine" what it would be like to see Tyler and Marla escape the hotel and in doing so the illusion of Marla and Tyler's existence begins to disintegrate.

We are not watching Tyler save Marla in this scene, we are watching Jack leave the hotel completely alone, yelling at the paramedics franticly about how Marla is infectious human waste (hence the use of the 3rd person when Marla is yelling at the paramedics.

Check the 3 slides above for proof or go to 50 minutes, 40 seconds in to the film to see it yourself.

Any 3rd person view will show they have no reflection (which is why we don't see it here, Jack is just telling us to imagine it - so we see them). This is just like at the end of the movie where we see the security footage from the garage. We see it is just Jack fighting himself alone, because Jack did not see the footage, we are just supposed to be imagining seeing it.

The blue arrow in the first slide is showing the reflection in the convex mirror as Tyler approaches it reflecting the image of the metal box/cables on the wall. In the second slide you can see Marla and Tyler coming around the corner, directly in the line of the view of the mirror - and all we see is the reflection of the box on the opposite wall (even though the mirror is pointed TOWARDS them).

In the 3rd screenshot they still have no reflection even though the paramedics, who are now behind them, have a reflection.

Marla Takes Control of Jack In the Laundromat

Marla opens 2 Speed Queen brand dryers and takes out multiple pairs of men's blue jeans. She then walks to the vintage clothing store and sells them. This all takes place while Jack is negotiating with her about sharing the support groups.

This marks the point in the movie where Jack is "becoming" Marla. If Jack is Marla then this means he is selling his own pants to the thrift store and figuratively surrendering his masculinity.

Consider this: What are the odds that two dryers right next to each other would contain only men's blue jeans and not some other clothing? How did Marla know those clothes were in there? Is there any other article of clothing that is more representative of Western "masculinity"? It is obviously a deliberate metaphor for Jack's masculinity being hijacked by Marla, his alter-ego.

Later in the film we see Marla wearing a pink bridesmaid dress she claims she "got at a thrift store." What if Jack, acting as Marla, bought this dress at the same time he sold his own jeans? This would make perfect sense since Marla is seen selling her clothes at a vintage consignment store, which is for all intents and purposes the same exact thing as a thrift store.

In fact, upon reading the script, we see that the vintage clothing store is literally labeled as "thrift store". Marla is likely hinting at Jack being the true owner of the dress when she says to Jack, "you can borrow it sometime," since she knows it is actually his.

Everything points to this scene representing the rapid change from Jack into Marla (Speed Queen…get it?) or at the very least the psychological transition of Jack into someone whose alternate personality is primarily Marla.

The Speed Queen dryers, only removing men's blue jeans, selling them in front of Jack and Marla's later admission that she got the pink dress at a thriftstore are all very obvious signs this is what is taking place. Fincher did not accidentally create this sequence, it was very carefully planned.

If the idea of a cross dressing Jack is hard to believe for some reason, just think about Jack's relationship to Tyler. Everything we saw Tyler do, Jack was actually doing or imagining himself watching.

It is only in the film's narrative that Jack shows us a flashback where for a few spliced-in frames Jack IS Tyler. If you accept that this is a fact of the film's narrative, then it is completely logical that Marla is just another, yet unrealized, figment of his imagination he is living through. This ties in heavily with my timeline theory.

At the end of the film we watch Jack run around frantically, without pants, after he has decided he wants Marla instead of Tyler and Project Mayhem. He has abandoned his masculinity entirely and is either accepting his emasculated self or is literally becoming a woman, depending on how you interpret the film.

This culminates in the final scene where we see the mirror image of Marla and Jack holding hands . Jack creates Bob, then Marla, then Tyler, then finally betrays Bob and Tyler to accept his place as Marla (notice how Bob and Tyler both die the exact same way: a gun shot wound blowing out the back of their heads).

Jack has accepted his emasculated self, simply chosen to identify as an actual woman or is only keeping Marla as his "main" alter-ego.

Tyler Takes Over Jack On the Airplane

The first time we meet Tyler in the film is on the airplane. Did you ever notice what happened immediately before Tyler shows up?

On the plane Jack is talking to a middle aged black woman who is wearing sunglasses that resemble Tyler's (see below comparison) and sitting next to Jack eating a meal.

Jack then begins fantasizing about the plane breaking apart mid-flight after it collides with another plane. After he snaps out of this fantasy, Tyler is now sitting in place of the woman. How on Earth could this be possible..?

 "It's called a changeover. The movie goes on, and nobody in the audience has any idea." - Jack

This means the woman does not exist and Jack is likely sitting alone, either talking to himself or imagining himself talking to the woman and to Tyler. We watched a woman turn into Tyler, sitting right next to Jack. What might this represent? Hmmm.

Furthermore, we see the woman is somewhat older and eating from a tray, which is an interesting parallel to how Marla provides food for herself: stealing Meals on Wheels trays of food. This scene denotes the transition from Marla being the prominent alternate personality of Jack, to Tyler taking over.

Jack boarded the plane as Marla, the destruction sequence is showing us the "end" of Marla and then he "becomes" Tyler. This explains why he loses his baggage once he gets off the plane and is so confused as to why it was vibrating. Jack didn't pack his bag, Marla did!

He is now Tyler, and this is why the damaged cardboard box is the only luggage left on the conveyor belt, since this is Tyler's luggage.

Fincher could not have made this much clearer when you consider the emergency exit sign above the door (last 2 slides above).

The emergency exit image shows a woman on the first section of the diagram, she then opens the exit, then in the final image is replaced by a man standing in her place.

You can tell the female turns into a man by the change of clothing and hair between the first and final image of the emergency exit diagram.

Testicles and Balls, Marla is Jack Post-Testicular Cancer

If you look at the film as a commentary on the emasculation of men in Western culture, it makes sense. But it goes deeper and helps explain why Marla and other characters are not real.

There is an over-arching theme of "removing" manhood throughout the film.

Whether literally removing someone's testicles or through references to sex toys. In either case it suggests the removal of what defines a man.

The metal cage behind Jack literally containing balls in the testicular cancer support group.

What is the significance of this? Why would members of Project Mayhem have such a fixation on removing men's balls?

Why would Marla go to a testicular support group in the first place?

Why would testicles need to be removed? It does not make sense unless you consider the idea that very little of the film is real.

For example, in the police interrogation room it makes sense that the police officers say "We gotta get his balls" since Jack would have anxiety about figuratively "losing his balls." Jack has essentially pussied out of a major plan, he has lost his balls (figuratively speaking, of course).

If Jack is Marla then it makes sense that Bob and Marla are both members of the testicular cancer group. Jack feels emasculated, at first he only feels moderately insecure, so he imagines Bob there to help cope with his insecurity and anxiety about his actual testicular cancer.

He then creates Marla, who helps him cope but also represents his feeling of being literally feminized by the prospect of losing his balls.

If most of these things are not happening at all or are happening differently than they are presented (i.e. interactions with Marla, the support groups, etc.) then this evidence lends itself to the theory that we are simply seeing Jack's insecurities leak into the narrative through the coping mechanisms he created to suppress them.

Marla makes a really interesting comment when she says that she has more of a right to be at the testicular cancer group than Jack, since "you [Jack] still have your balls."

He says, "You're kidding…" and Marla says "I don't know, am I?"

This is a really telling exchange, particularly when you consider they have this conversation mere seconds before the Speed Queen scene.

It suggests that if Jack is Marla neither one of them can possibly know if he does still have his testicles, since Jack is already so far into denial he has created two alternate personalities as coping mechanisms already.

Big Rubbery One

Dildos are extremely prominent throughout the film and lend a lot of credibility to the fact that Marla is not real.

Dildos represent the fact that Marla is taking Jack's masculinity or that he is surrendering it, and this could likely be a metaphorical device used to illustrate Jack literally no longer physically has his testicles.

This would explain why we see Marla with dildos at the times and places that we do.

For example, outside of the support groups we see Marla smoking a cigarette when Jack goes to see if Marla is still attending groups.

In the shot, it is very difficult to see what she is holding in her hand as she lights her cigarette. If you adjust the color levels of the image, you can make out what is clearly a dildo.

Why on earth would she be holding this outside of a support group if she were actually real? It makes no sense what so ever unless this is all just being imagined by Jack as he is fondly remembering Marla and the support groups, only to remember that she (and the support groups) are the enemy of his masculinity, which explains why she is holding the dildo.

Did you ever find it odd that when Jack is hugging Bob for the first time he says, "strangers with this kind of honesty make me go a big rubbery one."

Have you ever heard this phrase used before? No?

That is because no one says it. It makes no sense.

Unless you consider more of his insecurities are leaking into the narrative. He could only be referencing the BIG, RUBBERY dildo that he owns.

Another significant place we see a dildo is on Marla's dresser, which is a very interesting place for it. When Tyler goes to save Marla, he leans against the dresser, causing the dildo to move. Marla then says, "Oh don't worry, it's not a threat to you."

This could be interpreted a number of ways. If Marla is Jack, and Jack is Tyler, then the dildo is likely not going to be used by any of them, so it is literally not a threat. In addition, if Tyler is a coping mechanism who represents masculinity, he presumably actually has a penis - so the dildo is not a threat - while Jack who has been possibly physically emasculated would see the dildo as a threat.

In addition, the positioning of the dildo on the dresser and next to the door lends itself to another interpretation that I feel makes more sense.

If Jack believes that this is where Marla stays, yet he is Marla, then this is a clever way of communicating to the viewer that Jack is leaving his manhood at the door when he arrives and takes on the role of Marla. This would also help add even more strength to my vibrating suitcase theory (below).

The Vibrating Suitcase (Dildos Part II)

So, what was vibrating in there anyway..? The security guard says himself…

This is one of the strongest points for Marla's non-existence. The most interesting part about this scene is that Jack is utterly confused.

If he had been the person to actually pack his bags, then surely he would understand what COULD be vibrating in the suitcase.

The security guard even says, "9 times out of 10 it's an electric razor."

But Jack continues to look at the security guard confused and says, "my suitcase was vibrating?" Implying he has no idea what could possibly be the cause.

However, if Jack is actually Marla, then Marla is likely the one who packed his bags. Which means there actually is a dildo in the luggage.

Jack acts totally confused about this because he himself has no idea he is Marla.

Think about it: the dildo is even sitting on top of the dresser, and Marla packed it.

The security guard even hints at this by saying, "of course it's company policy never to imply ownership in the event of a dildo, we have to use the indefinite article a dildo, never your dildo" and looks at Jack skeptically.

If you think this evidence does not make sense as "dildo" and "vibrator" are not the same thing, and that "dildo's don't vibrate", please click here (NSFW).

This is brilliant because the security guard is essentially saying we cannot say it's actually Jack's dildo, because we do not know he is Marla, it is indefinite and ambiguous on purpose.

The fact that it is a security guard telling him this adds even more weight to this theory, as security guards act as a clever and reoccurring theme in the movie as a metaphor for Jack's insecurities.

This also helps explain the box on the luggage carousel. This is likely the luggage that Tyler packed, or at the very least is supposed to represent Tyler's luggage being picked up by Jack while Marla's luggage has now been confiscated.

This ties in absolutely flawlessly with the transitioning theory where the woman sitting next to Jack becomes Tyler instantly on the airplane.

Jack then leaves the plane, his luggage is no where to be found (which is really Marla's luggage) yet Tyler's tattered, broken box is on the luggage carousel waiting to be picked up.

The fact that the security guard also refers to the baggage handlers as "throwers" is very interesting.

This is not a common term that is actually used, which you could argue is supposed to be funny, but if you accept the fact we are potentially talking about a character whom is either figuratively or physically becoming a woman, then this could be a reference to the homosexual slang "pitcher."

Marla and Jack Live In a Hotel, the Paper Street House Doesn't Exist

The house Tyler lives in, where Jack moves into and Project Mayhem uses as a base does not exist.

Equally interesting is Marla does not have an apartment…or a house…she lives in a hotel.

This is information we never directly receive during the entire film, unless you are paying very close attention. Marla clearly lives in a hotel, but Jack somehow does not even know this even after having been at her hotel room.

Who else do we know that spends almost all of his time in hotels? Oh right, Jack.

When Marla calls Jack to tell him she is committing suicide, Jack says, "just picturing Marla throw herself around her crummy apartment" but we know that Marla is staying at a hotel because the exterior shots of her "apartment" have a neon sign in the background that says "Rooms".

If this isn't enough to conclude she is living at a hotel, in additional exterior shots we see the hotel name (two different names are shown), Hotel Lindy and Bristol Hotel.

The latter of the two being the actual, real hotel in Los Angeles where the exterior shots were filmed.

In the beginning after meeting with Tyler after his condo explodes, Jack says "ah, I need to find a hotel."

This helps explain Jack's distaste when Marla begins spending more time at the Paper Street house, why Tyler and Marla cannot be in the same "room" together (because he cannot be two people simultanousely) and why Project Mayhem causes the Paper Street house to turn into a "living, breathing thing".

Jack says, "She invaded my support groups now she invaded my home" and explains why Tyler is adamant about not being in the same room.

The personalities are losing their compartmentalization (think about it, Marla begins living at the Paper Street house even, then Bob moves in and Project Mayhem, they all wind up in one house or one "compartment") and Jack is losing his sanity as a result, which we watch deteriorate through the rest of the film.

The house itself is dilapidated because it is a visual metaphor for Jack's mental break down between the different personalities he has manufactured.

The Paper Street house now clearly becomes just an illusion, even the name of the street of the house points to this. A "Paper Street" is a street that an engineer has planned for, but has not yet been constructed. The house does not actually exist, Jack just imagined it.

This explains why Bob is buried in the garden and essentially "recycled" into Jack's psyche at the Paper Street house.

Recycle Your Animals

This explains the "Recycle Your Animals" bumper sticker on the Lincoln Towncar car Tyler and Jack crash with two project mayhem members in the back, and why Tyler refers to Marla as a "predator posing as a house pet." And yet another nail in the coffin is Marla comparing her "death rattle" to a "hair ball."

Bob is even referred to as "the big moosey."
We even see that as Jack gets off the bus at the Paper Street house, the advertisement on the bus (which is not easily visible without adjusting color levels) hints at this, right before he enters the Paper Street house where the "animals" are (Bob, Tyler, Project Mayhem).

Click the images to see the full text on the bus advertisement then view the following frame of Jack walking into the illuminated Paper Street house.

Myself, Myself, Myself, Myself

Once Jack leaves Marla's place after examining her for breast cancer, he runs into Bob. We can see written on the wall behind Jack the phrase "Myself" 4 times, in a column. In other shots we can see the full writing actually reads "I love myself."

Why does Bob appear at this point when we haven't seen him since the beginning of the movie?

This is why Bob is profoundly thanking him after the fight. By doing this he has given Bob enough attention and validation as a separate identity that he is now "alive" to his psyche again, he is again a living person as far as his mind is now concerned.

Marla has just told Jack she stopped going to the support groups, why? It's actually because Jack is no longer at the support groups, that's the only reason.

The same goes for Bob. Bob hasn't been going to the support groups because now Jack is no longer there, so they do not exist without him there since they were his coping mechanism for dealing with his use of the support groups and nothing more.

His two other personalities are now using this opportunity to try to get back into his life. Need even more proof? Did you notice anything interesting about the screenshot above? Scroll back up the previous screenshot of this same scene where Jack is walking out of Marla's hotel after checking her for cancer.

The spray painted words are not there. This is telling us that now there are 4 main people that Jack is essentially operating as, including himself in addition to Bob, Marla, Tyler. This could not be anymore obvious as the writing "I love myself" is literally written on the wall.

The only characters throughout the entire film who we ever know the full names of are Bob (Robert Paulson), Marla (Singer) and Tyler (Durden). These are the only "real" people as far as Jack is concerned.

Tyler Saves Marla from Committing Suicide

Even Jack says "now why would Tyler think it's a good idea to save Marla?" This is partly a sly reference to the twist ending, where we discover Tyler is Jack. But if you take this deeper you realize it's because if Marla dies, Jack dies, meaning Tyler also dies.

If Marla is committing suicide and she is also Jack, then it means Jack will die as well as Tyler. In other words, we are watching Jack lying in the bed trying to commit suicide - "calling" Tyler at the non-existent Paper Street House. This is the incentive for Tyler to save her. If Jack dies, everyone dies.

This is why Jack asks this rhetorical question of why Tyler would waste his time saving her. Why else would Tyler save her if she were an actual person? It makes no sense.

In addition there is this: and this is a theory with only circumstantial evidence, I admit, but it makes sense. The Xanax Marla tries over dosing on is the Xanax that the doctor prescribes Jack at the beginning of the film, which we never see happen.

Jack requests two pills, one of which is an anxiolytic like Xanax.

We know Jack initially sees his doctor at the beginning of the film to get medicine to help him sleep and specifically mentions two separate kinds of pills in the voice over.

Jack has in mind Tuinal and Seconal, both of which share very similar properties to Xanax, being anxiolytics and hypnotic drugs.

What if when Jack is at the doctor, he is actually getting diagnosed as having testicular cancer, and is in fact prescribed these drugs to help cope with the anxiety (along with being told to attend cancer support groups)?

Left In the Copier

Jack's boss finds the fight club rules in the copier and confronts Jack about them. Jack replies with something Tyler might say, then says "Tyler's words coming out of my mouth. And I used to be such a nice guy."

Immediately following the phone rings and it is Marla saying she thinks she has breast cancer.

She interestingly says "my tits going to rot off" This is carefully worded, since it implies she is dead and decaying or falling apart.

Why is this? Consider that up until now Marla only seems to call out of desperation, and within the context that she is dying or about to be gone forever (her suicide call first, now she is "decomposing").

Is it really a coincidence that Marla calls him right after we see Jack being taken over by Tyler's personality (i.e. the words he chooses to use to tell his boss off?)

This is Marla saying to him that she is basically dying and her personality isn't needed anymore, she's trying to get his attention so she can continue to exist to Jack. If anyone thinks this is a stretch, consider who pops up out of no where immediately after Jack leaves Marla's, where he checked her for cancer. Bob. What are the odds that 2 previously forgotten characters appear within 60 seconds of each other, both in need of Jack's attention and help?

What's really interesting about this is that if Marla isn't real, then it means the phone never rang. Which means Jack said something that was certainly disturbing to his boss, but even more disturbing is that he just picked up a telephone that didn't even ring and then told his boss it was important and he had to take the call.

This would explain the boss looking disturbed and genuinely put off. It also provides more proof that Marla is simply another figment of his imagination in that she is a coping mechanism. The more she is needed, the stronger she becomes. This applies to Jack's other personalities as well.

Jack has just been found out along with his association with Fight Club, an enormously panic-inducing experience, triggering the need for his coping mechanism, Marla, to help him through the ordeal.

Right on cue, the phone rings and it is Marla to help get him out of the situation, literally asking him to leave work immediately and come to her house to check her for breast cancer.

Jack's boss says something quite revealing as well, "Pretend you're me."

Self Improvement is Masturbation

This is a big one. There are a ton of references to masturbation and "fucking yourself" throughout the film. The most notable scene is where Tyler and Jack board the bus and Tyler says, "Self improvement is masturbation, now self destruction…" and trails off.

The actual full sentence Tyler was supposed to say, according to the actual script, is "masturbation is self improvement, now self destruction is the answer."

Fast forward to when Tyler saves Marla and they are now in the habit of constantly having sex with each other. If masturbation is self improvement, and if Marla, Tyler and Jack are all the same person, then Jack is masturbating.

So…where does the self improvement come in?

This is proof that Marla is not real, and is in fact Jack, since he is essentially masturbating in these scenes through his self improvement as the house is destroyed. This ties in later with the demolition of the credit card buildings.

Breast Cancer Time Change

When Jack goes to Marla's to help her check for breast cancer it is still day light outside. His exchange with Marla takes less than a minute, yet when he leaves it is entirely dark outside. Immediately out front of Marla's he bumps into Bob. He had just saved Marla "from dying" now Bob appears, someone we basically thought was gone/dead up until now.

Where did the time go? We know Jack didn't hang out with Marla for an extended period of time since we watch the entire exchange and right after checking her for breast cancer he says "Are we done here?" and rushes out. This takes place in just seconds.

This change in time makes sense however if he simply lives at the hotel, and when he left the hotel was transitioning from being Marla to becoming Jack again. Why would Jack think it's necessary to help Marla check for cancer anyway?

If you consider the idea that Marla is in fact Jack, then it makes perfect sense. If Marla has cancer, Jack has cancer - so he has to check himself for cancer. This explains why Marla offers to return the favor as well.

She says she will check his prostate, which is interesting since it connects to the idea that he is somehow removed of his sexual organs or they are compromised by cancer.

Marla's anxiety about having cancer is figurative in that it represents her impending death if Jack doesn't acknowledge her, but it also, again, represents Jack's anxieties about his actual cancer leaking into the narrative through his manufactured alternate personalities.

Infectious Human Waste

Everyone remembers how Tyler Durden makes his soap - stolen fat from the liposuction clinic. In the scene where they go to steal the fat they alert the attention of the security guard (more on this later) and hide behind a dumpster marked "infectious waste". To be more specific, the contents of the dumpsters are in fact infectious human waste.

When Tyler had gone to save Marla, we see her yelling at the paramedics and emergency responders that are coming to save her that she's "infectious human waste." Even more interestingly she is speaking about herself in the 3rd person.

This makes perfect sense since Marla is Tyler and in this scene we are actually watching Jack running away from the hotel and speaking about Marla.

She's referred to as "infectious human waste" because Tyler and Jack know this, so she knows it. Just like Jack said in the first 30 seconds of the movie, "I know this, because Tyler knows this."

What are the odds that Marla, if she were her own individual person and not a figment of Jack's imagination, would choose to use the word's "She's infectious human waste!" to describe herself in the third person when we know that Jack and Tyler literally use infectious human waste to make soap. This is a deliberate connection the director was trying to make.

This is why Tyler is wearing rubber gloves when he has sex with Marla.

"I Want to Have Your Abortion"

After Tyler and Marla have sex Marla famously says "I haven't been fucked like that since grade school." This line in the film was actually improvised by Helena. The actual line in the script is "I want to have your abortion." This is an odd choice of words even for someone who is supposed to play a dark and cynical character like Helena - it kind of doesn't make sense.

However if you consider that Marla is Tyler and Jack, then Jack is fucking himself, and will ultimately destroy himself - essentially an abortion of himself. This makes her choice of words make much more sense. "Self improvement is masturbation, now self destruction…" is related to this also.

Tyler never finishes his sentence. Since we know that Tyler was actually supposed to say, "masturbation is self improvement, now self destruction is the answer" (based on the script) then this makes perfect sense. Marla is Jack, Jack is also Tyler, when Marla and Tyler are done having sex she says "I want to have your abortion" which is the same as self destruction, since they are the same person.

Cinderella and the Glass Slipper

Marla says something very interesting after having sex with Tyler, as she comes downstairs while Jack is feverishly trying to scrub his jacket clean in the kitchen. Earlier in the film we saw Jack go into the bathroom to find used condoms in the toilet.

Marla says…

"You know, the condom is the glass slipper of our generation."

For those of you who might not know, this is a reference to the fairy tale Cinderella. A story of a woman who puts on a piece of clothing (a shoe) and undergoes a transformation. Remember the gown Marla is wearing?

Marla even says herself… "It's a bridesmaid's dress. Someone loved it intensely for one day, and then tossed it."

Was Cinderella a bride's maid? No, but she was a "poor maid" (literally taken from the Cinderella text) and the entire story of Cinderella occurs in one day and completely revolves around the transformation of characters.

When Jack is first talking about Tyler having sex with Marla, he says,

"How could Tyler not go for that? Night before last, he was splicing sex organs into Cinderella."

Why would Marla make this comment about the glass slipper and then why would Jack conveniently make such a direct parallel with his comment about Tyler SPLICING IN SEX ORGANS (literally) into Cinderella?

Marla saying this implies she is Cinderella in this metaphor, Jack then says that it makes sense that Tyler is ok with this - since he is used to splicing in sex organs to Cinderella. There's one problem here though, Jack says this about Tyler before Marla ever makes her comment about the glass slipper.

This is consistent with other points in the film where we see that characters seemingly "share" what they know with one another, i.e. "I know this, because Tyler knows this." because ultimately, they are all sharing the same brain.

And sure enough, how many condoms are in the toilet, despite the script stating there should be 6…? 4 (one for each  main alternate personality).

In the script the original Disney film that is referenced in Jack's comment is Little Mermaid (instead of Cinderella). This shows that Fincher deliberately made a change to the script in order to make this connection between the two.

Think about the implications of making a parallel between Fight Club and Cinderella, particularly with Rule #2. This would make Bob LITERALLY the fairy godmother, which is completely congruent with my statements so far about him being some type of feminized God and/or nurturer.