The lie of Arcadia

[Excess]

This is a headcanon that I came up with while musing on the nature of bargains and the folly of bridge-burners.

Suppose they, the bridge-burners, struck an unprecedented blow against the hedge and tore open a rift in reality. One of them stumbles out alive and thoroughly crazy from revelation. As his sanity was being pieced together to learn what happened the courts interfered to keep their silence, while the debate rages if maybe it is time to come clean.

The secret: ironside and Arcadia are one and the same. Not all Faery magics are broken by iron, like some huntsman and the Mask. The hedge is some kind of hyperbolic space with the Wyrd dictating a maze made of terms and illusions. When changelings open a portal to the hedge what actually happens is the Mask drops and the Wyrd reroutes their instincts and spatial perception.

As omnipresent beings the Gentry are limited by terms of interaction rather then distance while the Wyrd is universal. People don't "go" to Arcadia nor do they "escape" from there, for it is here. The Gentry are our close neighbors separated by a line transparent to their Names. Travel to and from is a circle in strange space. The constitution of the Hedge includes the limit of "distance" and so makes escape possible.

[Neos01]

Well, i think that it must be said that meghan fitzgerald canonized the true nature of the hedge in dark eras 2, as the barrier between human minds and the collective astral soul.
By some interpretation, this could mean (MY INTERPRETATION) that the hedge is a realm of EGO, human ego with arcadia and its gentry, animal ego probably with old arcadia and its huntsman, and a representation of social interaction in the hedge.
That said, i think that other speculations must start from the info provided in dark eras 2.

[FallenEco]

If we take the "Mysterious Frontiers" DE2 chapter's interpretation of the Hedge as cannon (which it is, as far as Chronicles/nWoD has cannon), it doesn't mean that 'Changeling Arcadia' isn't directly parallel the mundane/ironside reality.
We do know that it isn't 'Mage Arcadia', which as a Supernal Realm is presented as more of dimensional frequency or super-strata of the Fallen World, rather than a material reality. The Astral (the collective soul place the Hedge briefly touches) is implied to be closer to the Supernal Realms (including M!Arcadia) but is not confirmed.

What we know is; Changeling Arcadia is not the Supernal Arcadia, can be reached via the Hedge, was originally inhabited by Huntsmen and currently ruled by the various feuds' of Gentry; who appear to be sentient Names/Titles that can take the forms of individual people (Actors), items (Props), numerous nameless hordes (Wisps) and even the land itself (Realms).
Oh, and time doesn't necessarily interact with C!Arcadia the same way it does with Earth. Not quite Mummy 2e's Duat level of different but certainly more than just losing track of time; the authors have called that out consistently. Having characters toil away in Arcadia for decades, coming back the day they were abducted while having others escape mere days after their capture only to find a century has past.

None of this stops you from making this 'lie of Arcadia' true in your game, or at your table. But it might help if you think about these issues and come up with some answers for your players.

Like having Arcadia separated from the rest of Earth because of some kind of oath, like an ancient king lost a bet to one of the Others in antiquity for half the World. Like Khonsu, maybe they gamble with Time, they certainly have enough Contracts that play around with it. Maybe the Hedge works as a bridge because everyone dreams, but the souls of 'Arcadians' are barred from the rest of the Astral because the Gentry have claimed them for themselves. These tortured souls form the basis of the Huntsmen as the Gentry bind them into new bodies rather let them rejoin the World Soul.

Is any of the last paragraph cannon? I doubt it. But does it make a good story and support the premise Excess posted? Maybe.
Personally I feel it needs work, but not my monkeys, not my circus. Just thought it might help

[Excess]

I am a bit confused on some subjects. I thought the hedge as mind/soul divide was not canon, nor was anything in dark eras. I hear that dark eras is a dumping ground for concepts that were discarded in revision during the formation of second edition.

As for how my idea works: I am thinking it had to do with pledges of interaction. As the Fae made such deals space and perception warped to enforce them. As time passed they accumulated.

[Tessie]

I hear that dark eras is a dumping ground for concepts that were discarded in revision during the formation of second edition.

It's not completely wrong, but it's also a complete misunderstanding of the situation. All material in Dark Eras is supposed to be completely canon (as far as anything in CofD is canon). What you might've heard is that specifically Changeling material in the first Dark Eras book isn't compatible with the actual game because that material was written during the development of Changeling 2e, and that version of Changeling 2e was eventually discarded due to circumstances. It's certainly not a dumping ground for concepts they didn't want to include in the game proper.
The part about the Hedge as the Astral barrier is included in Dark Eras 2, which is up to date and compatible with second edition, and thus just as much canon as any other supplement for this edition.