Epistemic status: I’m not any kind of expert on any of this. Even if I were, Grand Unified Theories of anything are inevitably wrong. I’m not so much trying to convince anyone of anything as I am explaining my own conceptual framework for multiplicity.

Disclaimer: I play fast and loose here with terms like “you”, “self”, “someone,” “person”. Language is hard, and English isn’t built for this. I am firmly in the camp that, not only is it polite to treat multiple persons sharing a brain as separate people, you’ll broadly have a more useful model of the world if you do.

1. The Ego

There’s a parable I heard once, although I unfortunately can’t remember where. I paraphrase it here as best I can:

Gazing into the void of my own mind, I cry out: Who art thou, man?

The void whispers back: Who is it who asks?

The one who asks is the ego. If you have an internal monologue, your ego is the one who speaks it. If you ask yourself why should I care more about this body than about seven billion other bodies?, you might (or might not) answer, this body is the only one from which I experience the sensory input. Your ego is the ‘I’ who experiences that sensory input.

You might think of your ego as you. Whether that’s true is a question for the philosophers; personally, I’m inclined to identify you as the whole of your brain and body and the processes running on them. For the purpose of this post, it might be easiest to conceive of your ego as a story you tell about yourself – a sort of ongoing autobiographical narrative, constantly being written, constantly under revision. (Of course, your ego is not only the story, but also the storyteller – both Homer and the Iliad. But, like Homer, it is of dubious provenance, best defined simply as the author of the Iliad.)

2. Ego Death

The ego is less resilient than you might expect (or, perhaps, hope). Ego death is a known phenomenon, brought on either by psychedelic drugs or just by thinking real hard. The experience seems to be more or less one of noticing that the self-narrative of the ego is optional, not a core part of one’s being, and stepping back from it. Thought and experiences continue, but there’s an often-referenced sense of “oneness with the universe”; without the narrative of the ego, the delineation between self and other becomes less clear.

Researchers into psychedelics and ego death say a lot of things which I find suggestive about the underlying mechanics of the ego which enable multiplicity. A few exemplary quotes from this article:

“[a] self-model, an inner image of the organism as a whole [is] built into the world-model, and this is how the consciously experienced first-person perspective develop[s]”
“apparently “selfless states””
“Attribution to exogenous rather than endogenous causes could result in a loss of “perceptual mineness” – the background feeling that my experiences are “mine””
“a more profound dissolution of the sense of being a self or “I” distinct from the outside world”
“the ownership of mental phenomena seems to subside and “the individual may feel like a bystander watching the mental activity of another person””

In other words, there appears to be a lot of evidence that it’s entirely possible to separate the ego – the sense of being-oneself, being-a-particular-person – from the thoughts and experiences associated with a particular brain and body.

I suspect that garden-variety dissociation is a weaker version of ego death. The descriptions certainly track: there’s the same sense of being a bystander in one’s own life, watching experiences which are not one’s own, of not-being-a-person. I’d also point at the severe distortions in perceived passage of time associated with both states.

3. Stepping Back, Stepping Forward

OK. So, if you’ve come this far: let’s posit that it’s possible to temporarily dissociate, or “dissolve the ego,” or stop adding the events happening to a certain body to a particular self-narrative. What’s more, it’s possible to do this not only while lying on the floor tripping out, but while going to work, carrying on conversations, and otherwise putting forward a reasonable appearance of a normal life.

There’s an obvious question to ask yourself, when you’re dissociated, distantly watching experiences and decisions which appear to be someone else’s: who is the someone else?

I’d suggest that the answer, generally speaking, is Nobody. After all, it’s not as if a demon has risen up from the depths to possess your body. You-the-ego have simply ceased to consider this part of your self-narrative. Anecdotally, interacting with someone severely dissociated feels uncannily like interacting with some kind of p-zombie: the lights are on, no one’s home.

But what if someone moved into the metaphorical empty house?

Look: humans clearly have the ability to juggle more than one self-narrative, and it’s obvious why we might. It’s my strong impression that the ability to model other people is hackily using the same machinery as the self-narrative. (Possibly it’s the other way around, and we got a self-narrative because we had the machinery for modeling other people.)

You probably have a little model of a parent sitting around inside your head, occasionally piping up to critique your life choices. You might “put yourself in the shoes” of someone who annoys you, or get into the head of a character you’re writing. I’m not suggesting that these are full-blown egos; but they’re running on the same machinery. (Hell, if you’ve ever had an argument with yourself, I think it’s plausible that you’re effectively running one-and-a-bit copies of your ego, to give yourself someone to argue with.)

In some cases – as far as I can tell – that machinery spins up a new narrative, a new ego, and where the old ego stepped backward, the new one takes the front.

4. What Makes A Multiple?

Obviously not everyone who might develop more than one ego does so. I have some thoughts on what contributes to this happening.

(Within the multiplicity community, this is where I get really controversial. I might as well make it clear now: I’m firmly on the “endo” side. I don’t think that trauma is necessary to become multiple; nor do I think it has to occur before a certain age. More on that shortly.)

One contributing factor is clearly dissociation. DID is a dissociative disorder, and I think all forms of multiplicity probably involve dissociation. It seems obvious how this could be a causal factor, in a sort of “nature abhors a vacuum” way: if you’re spending a lot of time with nobody running your body, someone might take shape to run it. Or, more carefully: if there are lots of experiences happening which are not part of your self-narrative, and your narrative machinery is spending a lot of time sitting idle, it’s only natural that the machinery should get to work on printing the first chapter of a new autobiography.

(This amount of dissociation naturally correlates highly with trauma. It’s not surprising, under this framework, that you would get the classic DID case of the child whose second “self” handles the brunt of sexual abuse. All you need is a child who spends a lot of time dissociating while being sexually abused, and unfortunately those are not in short supply.)

Another is conceptual availability. People tell the stories which are culturally available to them, and self-narratives are no exception. It doesn’t seem surprising that it’s easier to start running a second self-narrative if you’re aware that’s a thing that’s possible. In cultures with different notions of multiplicity, the additional narratives may be stories of demons, spirits, etc. In the extreme cases, multiplicity can sometimes be deliberately induced by intense meditation, just as ego death can be; this is usually referred to as “tulpamancy.”

A third is social intelligence (and, to a lesser extent, generalized intelligence). This is, I suspect, less a matter of causation than of correlation. Someone who has a lot of spare power on their self-narrative machinery is going to find it easier to spin up a second ego; they’ll also find it easier to model other people. My understanding (though I don’t have studies to hand) is that DID correlates with high IQ, which seems very plausible to me.

5. So About That Weird Memory Stuff

The stereotype of someone with “multiple personalities” heavily features memory gaps – waking up somewhere with no idea how you got there, leaving notes for the other people living in your head, finding out that your headmate is a serial killer, etc etc etc. In practice, many people who identify as multiple have totally shared memories among their headmates; sometimes the presence or absence of unshared memories is used to gatekeep “real multiples”.

I’ll be perfectly honest: for a long time, I thought that headmates not sharing memories … probably just wasn’t a thing. It seemed like the sort of thing that people would have strong incentives to claim – maybe even to convince themselves of – in order to get others to treat them as separate people. And I’m cautious about memory claims; it seemed uncomfortably close to the whole “recovered memories” debacle.

But then I got to know a system who didn’t share most of their memories. I absolutely trust them to be reporting accurately on this. If they were being less than truthful, they’d be doing a frankly stunning job of tracking who knew what information, not to mention some Oscar-level acting. I have literally had one of them wake up confused in my bed. I regularly consult them on Christmas presents for each other. I don’t think they’re lying.

These days, I suspect it’s the same underlying mechanism as dissociative amnesia. Dissociative amnesia seems to be relatively common in children with a history of severe trauma, and although recovered memories aren’t typically reliable, it seems plausible enough that those memories are still walled off somewhere in the brain. In the case of multiples, then, there’s just someone living in the walled room, who can access memories that aren’t accessible to other people in the same brain.

Given that theory, I’d expect unshared memories to be more common in multiples with early childhood trauma, which indeed they seem to be. They’re also a required diagnostic criterion for DID; I suspect this can mostly be chalked up to the fact that anyone who can be in the closet about multiplicity usually is, and memory gaps make it very hard to stay in the closet, so the mainstream usually only finds out about cases with memory gaps.

6. Early Childhood Trauma

This is the controversial issue I referenced earlier. How does early childhood trauma interact with multiplicity? Do you have to be traumatized before a certain age to be “really” multiple?

Empirically, this just doesn’t seem to be the case. My impression is that sufficiently severe trauma in sufficiently early childhood – before the ego is entirely “firmed up”, whatever that means – can cause a split which “solidifies” the way typical singlet egos solidify, such that the system is less prone to further splitting and merging, and generally has sharper divides.

Combined with the lack of shared memory that can come along with this kind of trauma, I think this makes multiples with early childhood trauma much more obvious, and results in them conforming more closely to the stereotypes of multiplicity.

By contrast, multiples who split without severe trauma or at a later age seem (again, in my anecdotal experience) to have less sharp divides. They’re more likely to have members of ambiguous personhood, to co-front comfortably, to share memories, to split and merge organically. My (entirely unfounded) theory is that this represents some kind of ongoing fluidity, as opposed to singlets and early-childhood-trauma multiples who have more solidified identities.

I really don’t have any evidence for this one, except that it matches what I see around me. Nor do I have a really good idea of the underlying psychological mechanics. But it makes a neat and predictive little allegory.