I agree. Even on the elven reproduction issue, David Gaider has said it doesn't have to do with genetics (because people insisted on there being a scientific explanation), but was actually due to the magic inherent to the elves. Nothing wrong with the science theorycrafting, it's interesting, but Thedas is a fantasy world that literally has magic in the blood, and logical, scientific answers aren't likely to be the answer in many cases.
*shines Team Mordin beacon into the night*
I don't have a good solution for this yet. Dumping this here to lay out the mental paths and roadblocks I've tried so far for anyone who wants to chew things over:
I don’t want to get too deep into pre-veil history and the “willing Fall from Eden”, but when the veil first went up, we have reason to believe that the newly-physical elves were all incredibly powerful mages. This makes sense in terms of what we think we know about magic theory: one full half of their being lies in the fade, while the other is physical. They are the intersection of Possibility and Decision- drawing Fade into the real world, and enacting their Will upon it to create Change.
On the other hand, (I could be wrong and for the love of god, stop me if this is a false assumption) but when humans first appeared, I don’t believe they were. Elves, as they were “whole” before the raising of the veil, had fade shadows, while humans came later, and were (at least at first) entirely physical beings.
I thought the key to understanding the emergence of magic in humans and why elf-elf unions are the only ones that result in baby elves might lie in the role of the essentially elven fade-shadow in determining the nature of the offspring. This sounds plausible at first, but eventually hits a snag I can’t resolve.
From all accounts, once a human has been introduced to a generational line, both immortality and pointy ears are lost: the offspring from that point on are physically human and mortal forever. Further pairings can restore more shadow with each successive generation, but it’s an asymptotic curve. The line can breed with elves for thousands of generations, get to a point where the children have 99.999% of a fade shadow, but the conduit will never be whole and thus the offspring never elven. These offspring will probably, however, be damn good mages, because again- that’s what the fade half of magic draws from.
Notice how Tevinter is all over this. Kind of. I think they may have forgotten exactly how it works, if they ever really did figure it out, because I don’t see them rounding up female elf mage slaves for breeding purposes. They’ve got the right basic idea, though, and it’s produced some pretty dang powerful human mages.
This concept also has some support from a conversation with Cole, I think. While he’s describing the fadey-magic element of their mortal being, Cole describes being a mage as “lips struggling to shape language your parents lived.” Thanks to the rules of inheritance here, if you went back far enough in any mage’s family tree, no matter which race, you would inevitably reach the pre-veil existence of spirit-angel-elves, a time when shaping the world with idle thought was simply how the universe worked.
Of course, taking on this perspective is where killing demons gets even more uncomfortable than it was when they were just potentially-friendly-but-still-otherworldly entities. It forces the idea that Solas wasn’t being rhetorical. Spirits really are people. Or rather, they are fragments- actual pieces of The People.
And in this context, Cole is bizarre. Really bizarre. On the one hand, I’m not sure he could be a mage as we know them, since he’s already poured his whole self into a physical cup, so to speak. There’s nothing on the other side to draw through- he is entirely and completely here. On the other, assuming he had mental control over the cup’s shape, then he really could change into anything he liked. He would essentially be a shapeshifter, which might explain how they fit into the world of Thedas.
Also, while it’s possible (I guess it shouldn’t be ruled out entirely?) that he was the fade shadow of the original human mage Cole, I’m not sure if this theory supports it. He’s able to sustain himself entirely from the fade, which seems like it should only be possible for a complete conduit, not the kind of tattered fragment-shadow that would have been attached to a human mortal. But maybe not. I’m starting to suspect the immortality-requires-intact-fade-shadow thing is a totally false assumption, but can’t put my finger on why just yet.
And while we’re on the subject of Cole: remember how squicked out Sera is by disembodied parts? She doesn’t realize it consciously, but that’s the source of her subconscious revulsion for him, not the fact that he’s a potential demon. A deep (Andruil) part of her recognizes him as “parts”- as creepy as a disembodied hand crawling along the ground, or a gruesomely severed head that continued to talk would be for a squeamish human. From an Elvhen perspective and sense of wholeness, he’s kind of intensely disturbing. Solas doesn’t seem to mind, but then, he’s seen his share of detached and fragmented People parts in his time.
Anyway. As much as fade-shadow inheritance theory seems to explain, there’s at least one massive problem.
If we assume that being physically elvish requires an intact fade shadow, and the completeness of an entity’s shadow has a significant effect on how much she can draw on the Fade, then all elves would have the innate capacity to be incredibly powerful mages. >w< This is not true.
From a different angle, if creating a child requires the actual literal donation of half your "soul" (though I know parents who would argue this is totally accurate) why wouldn't mage parents suddenly become much less powerful after their first child? And wouldn't the second offspring of two elves be... human?
It's a mess. For now I don’t see a way forward. The whole thing might have to be scrapped. Or am I missing a way to reconcile all of this?
Quickening and the Shems
Moving on, pinning down the reason behind the Quickening is even harder. The only piece that feels solid is that it must have had to do with a disruption to the elves’ fade-shadow as an effective conduit to the Fade, and thus their ability to pull from it to sustain their bodies indefinitely. And while the arrival of humans might have been a factor in the quickening, (it might also be entirely coincidental) it certainly don’t think it was as direct as “infectious mortality".
I don’t have a theory on this that I like yet, but here’s one possibility. Perhaps it wasn’t proximity to humans, but to what the humans were doing that caused it, as fade-shadows or fragments of fade-shadows were forcibly yanked from the Fade to be enslaved as spirit servants or destroyed as demons. Each piece lessened what was “available” for the next generation. Interbreeding would have sped the process, drawing even more from the elves as successive generations of human mages halved and rehalved the original intact shadows, making the shadows of modern mages like Viv and Dorian a patchwork of tiny individual shreds- in stark contrast to Solas, whose fade shadow is not only intact, but theoretically strong enough (in terms of its own spirit Will) to act independently from his physical body if necessary.
Anyway- trying to work this out reveals a huge hole in our understanding. If what we know of as “spirits” are the detached fade-shadows (and later, fragments of these fade-shadows) left behind when the physical half of a sentient being dies, and having a fully intact fade shadow is what makes you phenotypically Elvhen, then there can never be more elves than there were when the veil was first raised. Even if you assume reincarnation, that first post-veil generation is problematic. “Whole” ancient elves wouldn’t have been able to procreate: or at least, the offspring would have been missing a fundamental piece of being elven: a fade-shadow. Even assuming a system of reincarnation in which the shadow was guided back to a new mortal body, one of the ancient elves would have had to die before any future offspring could claim it.
It’s possible that such offspring were the original Humans: the purely physical, shadowless children of first generation elves. These “soulless” vessels might grant Mythal her first physical form in the new Thedas, but I don’t really like it, since that begs the question of what happened next, why they don’t show up again until thousands of years later, and when they do, why they’re so damn Willful compared to the Elvhen. There's definitely another hand in play here.
uh... so, I should cut this short before it's a thesis. It's all junk that doesn't really work yet, but maybe it's useful to spark the right idea in somebody else's head. Feel free to chop it all up as needed.