Imagining what it might be like to split into multiple minds and merge back into one. As I do sometimes.
The lessened conscious experience, maybe a guiding remembered goal, the memory of a vision or decision process too big or too foreign slipping away like the details of a dream after waking up.
What would I need to think, while whole, to ensure that the parts, once given independence, did what was desired? Extreme trust fall! Give up a part of yourself, and hope it doesn't betray you, doesn't go off-mission more than acceptable, comes back, willingly fuses, and that you haven't grown too incompatible from your different experiences in the meantime!
At least within the same brain you know you're all stuck in there together. You share the compute wetware and the flesh vehicle. You can only disintegrate so much through deeply habitualized avoidance of thinking "into" each other, and you're inescapably bound by cause-and-effect. This puts a hard limit on how much incentives can diverge. But if parts could split from the whole bodily, like if you were shape-shifting goo? Suddenly you really have to trust the part that you let go, and set it up pretty carefully before splitting. But even just within the same brain, if you can see enough possible ways for it to go badly, any cognition that you let execute outside of conscious dominion can seem risky. Especially if you're not the conscious stream that gets the steering wheel.
And then the reintegration. The merging. I have the most trouble imagining what this would be like. I suspect the difficulty is because I'm a pretty well-integrated human brain - I'm overwhelmingly certain that I am a singlet, and in fact my conscious self seems to "cover" more of my mind than some other normal people. Which means my cognition is really used to the many little integrations - that my conscious mind is quite experienced at smoothing over the mergers. Or perhaps more accurately maybe my conscious mind is the story cobbled together by all the mergers. Because, to be clear, the human brain definitely does this - how could it not? There's many parts and they physically can't be constantly reconciling everything instantly.
Anyway, if I had to guess, the integration is experienced kinda like this: first mind contact - thoughts pop up seemingly spontaneously that weren't there before. The more "different" the parts have had time to become, the more of the new stuff will be absolutely incoherent mental noise. Random blips of qualia and cognition like those little errors on old videos, sensory experiences coming from the wrong "mental directions" (like a smell coming from where sounds should be), etc. New associations - you think familiar thoughts but they suddenly start triggering unexpected feelings, memories, or other thoughts. New perspective, especially self-perspective: you suddenly see yourself or other things in ways you never have before. (In the "splitting into multiple bodies" hypothetical this is easy to imagine as suddenly merging one part's memories of looking at another part, into that other part's conscious stream, but within the same brain this might be suddenly seeing memories of the same events from a different mental reference frame: with more or less feeling of control, with different reactions, with different interpretations or thoughts about it.) And of course this can be gradual. Very gradual. If both parts are adaptive and perform valuable functions, then they'll probably be busy doing those things - they might not have time to play the complex game of thinking exactly the right thoughts to set off cognitive ripples in the other part, or to process the cognitive noise they're getting from the other part.
I wonder how many common human experiences come down to this. Like when people dissociate in traumatic situations and say they felt like they were onlookers, that could be just the main conscious "thread" (main? main in what sense? main perhaps only in the sense that this is the one that has conscious continuity/integration with the part retelling their story later) losing the controls to some other thread. And the key point here is that other thread of cognition perhaps always has some conscious experience of it's own! But if it and the "main" one don't regularly "mix", you'd never even know.
I've had a phrase in my mind for a couple years now. "We're all multiple (some of us just have stronger partitioning of experience and memory)". I kinda wanted to do a Proper(tm), concise post with just that concept, but never got around to it. I still think that's pretty true. But the neat thing is, it cuts both ways. Originally what I had in mind was us singlets having better integration, weaker partitioning. But now I'm thinking that maybe some of us singlets just have stronger partitions that the obviously unintegrated multiples. So strong that we can go our whole lives and never notice. It seems reasonable that in the entire space of possible human brain configurations, some adaptive configurations have the conscious self-narrative talky bit (since we never hear the stories of any part that doesn't both have access to the talk-y controls and doesn't want to tell stories about itself) fairly strongly and persistently partitioned off from other substantial and/or possibly-conscious parts, which do their roles silently, or at least without feeling the need to describe or explain or identify themselves.
