That last comment from Hussie on p.387 of Book 6 also uses the term “Persona Alchemy”, which he’s used before but I never really picked up on; it sort of explicitly ties it back to the concept of Platonic idealism used within Homestuck’s “actual” alchemy, and therefore to the sprites, which operate on the very same philosophy. It just ties everything together neatly.

p.3590

And then there’s this comment on p.382, which I can’t really think of a way to incorporate into any other post, but definitely feels like it needs to be included somewhere for posterity:

I remember Aradia whispering to her past self being a cagey way of implying that she was the one responsible for her own ghostly communications […] it’s kind of an interesting idea that this is demonstrating the mechanism which allows for her to receive messages from dead people. It would mean that ghosts are actually communicating with their memory of Aradia. And ghosts in their bubbles whispering to the memory of a psychically gifted person may serve as a conduit for actual messages being delivered to the real person. It opens up some deep questions. Is your memory of someone linked to the truth of that person’s existence in some way? The topic isn’t explored much beyond this one cagey whisper. But we do know that in Homestuck, ideas of people and things have a lot of power. Would it be unreasonable to think influencing the idea of a person might hold some sway over the physical instance of that person?

It’s an interesting angle to see inhabitants of the dream bubbles not just as the ghosts of dead timelines, but as memories of those timelines; literally the “versions” of people that live in their own or other people’s heads, yet another kind of reflection of the “true” Platonic idea of someone. Which I suppose is also literally the domain of the Mind aspect;

GC: HOW MUCH OF YOUR R34L1TY DO YOU TH1NK 1S M4D3 OF WH4TS 1N YOUR M1ND?
[…]
GC: 1F YOU S33 WH4TS 1N YOUR M1ND CL34RLY 4ND UND3RST4ND TH3 POW3R YOUR THOUGHTS H4V3
GC: TH3N YOU UND3RST4ND R34L1TY WH1L3 3V3RYON3 3LS3 1S RUNN1NG 4ROUND CONFUS3D 4ND 4NGRY 4ND UPS3T
GC: B3C4US3 TH3Y TH1NK R34L1TY 1S SOM3TH1NG H4PP3N1NG TO TH3M
GC: R4TH3R TH4N SOM3TH1NG TH3Y 4R3 M4K1NG 3V3RY MOM3NT W1TH 3V3RY THOUGHT