Lightweaving Theory (involves Hemalurgy)

[WayneSpren he/him]

So, I was wondering how Lightweaving could exist on both Sel and Roshar. I mean, Brandon's never put a magic system on two shardworlds before!

 

Answer: Hemalurgy.

 

Hemalurgy takes Investitures from something and bestows it on something else. In the process, the Investiture becomes a bit weaker. This developes my theory that lightweaving is originally from Sel, but eventually came to Roshar via a Worldhopper Hemalurgist. For example, if Hoid or Nazh went to Sel and took a Lightweaver's power, then gave it to a person on Roshar, they would gain Lightweaving. However, it would be weaker, which explains why Roshar's version of Lightweaving is harder to do. 

 

If Lightweaving can be hereditary, or if Shallan has a bit of metal in her somewhere, this all makes sense.

 

 

[MoS03]

You've seen a third form of light weaving, in SA. Hoid is originally from a planet called Yolen, which is also the planet Adonalsium originated from. As each Shard (Ruin, Honor, Cultivation, Preservation, Odium, Dominion, Devotion, Endowment) is a piece of Adonalsium, a lot of the original Yolish magics have proliferated via the Shards. That's why we actually see a lot of cross-planet magical similarities. Lifesense from Breath seems to operate similarly to Bronze in Mistborn, Lightweaving on Roshar, from Hoid, and on Sel, Seons on Sel operating similarly to Bonded Spren on Roshar, etc.

It seems you have some Cosmere information to inhale (and inhale you will, it's fascinating stuff). I actually envy you getting to learn this all the first time.

If you've read the whole Cosmere, these forums have a lot of fantastic information. There are, however, spoilers abound, so be careful.

Anyways, as to your theory, it may certainly be possible, but the amount of janky shenanigans that would need to occur just don't seem likely. It's easier to explain with the Yolen tie-in.

[Moogle]

This pops up because there's a limited amount of things magic can do, they're not actually the same system:

BRANDON SANDERSON
Thing is, some of the magic systems do cross worlds, and have before. And that has not happened obviously; you haven't really seen it. Right now Liar of Partinel [an unpublished book —ed] and Stormlight Archive share a magic system, because with the unifying theory of magic there's a certain number of things that magic can do, and there's a lot of different ones, but when they get similar they tend to work in the same way. So Lightweaving shows up in both books. I may change that for Liar of Partinel, but it's kind of integral to that book and it's kind of integral to Stormlight Archive right now too. This is one of the reasons why I had to decide to do either Dragonsteel or Stormlight Archive as the big epic.

Some of the magic systems have been discovered on different planets, and some of them do work. A lot of them don't, but some of them do. It depends on your spiritual DNA, what people are able to do, and things like that. But, if you find a way to do illusion magic in one of my worlds it's going to work pretty much like Lightweaving, regardless of which planet you're on. If that makes sense.

Footnote
Several suspect that Hoid is using Lightweaving when he is talking with  Kaladin in Way of Kings.
(source)

 

Sel's magics don't work off-world, so even if you got a someone with a spike from an Elantrian to go to Roshar (without a lot of complex workarounds, anyways), they wouldn't be able to do AonDor. (Also, AonDor requires you to draw symbols in the air, and Shallan never does this.) Because of this, the Hemalurgy theory doesn't really seem to work in my mind.

[The Honor Spren she/her]

I would say the similarities are just because magic in the Cosmere is all done with investure in some form. The shards were once part of Adonalsium. There are other similarities as well. Elantrians are like Returned in some ways. Using allomancy and becoming a Radiant both require being broken in some way. Soulcasting is remarkably like soulforging. Again, I think this is just because all of the magic systems were one once.

[Suspense]

Just because they produce similar effects doesn't mean they're the same magic system.  I would consider them completely different systems: on Sel, AonDor uses symbols to access the power of the Dor, while on Roshar the investiture--stormlight--is used directly.

[VindicationKnight he/him]

There are similarities given that all Investiture magics are based on the same principals, but the exact details vary, Aon Dor Illusions have less of a spiritual component than the Rosharan variant,which is closer to the original Yoleish method according to the WoR Ars Acarnum.

[ARARITA he/him]

everyone seems to have forgotten one of my favorite scenes :

 

Warbreaker has Lightweaving ..story and sand included

[DreamEternal]

Yes, but that was Hoid. He is, like, everywhere.

[Emerald101 he/him]

everyone seems to have forgotten one of my favorite scenes :

 

Warbreaker has Lightweaving ..story and sand included

 

The thing is, that even though it's happening Nalthis, it isn't illusion accomplished by use of a Nalthian magic system. It's (presumably) Yolish in origin.

 

Edit: punctuation

Edited July 6, 2015 by Emerald101