Another difference is that the eidolon becomes an independent branch of the original. From that moment, there are two of the original. This is not the case for the dream-traveler.
In IT terms, the astral body at first SEEMS to be a "client" of the corporeal body (this is the relationship Roy seems to be driving at). When the soul "returns" to the corporeal, the astral body and any child processes it has created (weapons, people, etc) are destroyed. This is efficient since it would other cause a lot of useless corpses to be left around.
It is actually more complex than that, and somewhat to the contrary. The astral body is not supported by the corporeal form during dream-travel. It is robust and self-sustaining (without the NEED to take food). During dream-travel it appears that actually the astral body temporarily becomes the parent process and the corporeal form the child process (the unstable dependent process). I say this because:
* If the corporeal body dies, the astral body can continue to run on its own without debility.
* If the astral body dies, this is a catastrophic crash: You are left with the astral corpse undestroyed (a "zombie" process) and the soul cannot "reboot" on the corporeal side. The soul on the astral side is claimed by the Increate.
When the soul moves to astral form, the "system" erases the version on the corporeal. This prevents identity confusion when the soul is re-integrated. When the soul successful returns to corporeal, it is re-written to the corporeal form before destroying the astral. This is why killing the astral body is catastrophic but killing the corporeal body is not.
Not that Wolfe was likely thinking in these terms, but the model is, I think, an accurate representation of the rules and limitations.
Additionally, I think the Rajan could afford to be non-chalant about being "not really here" during dream-travel because he could return at any time. This is not the case for anyone traveling with him. They could be marooned at the will of the Rajan and they could not bug-out at the first hint of danger.
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