So I got Ancient Magic today, and I must say, it's probably the best Ars book yet, in my opinion. I love it!
One question came to mind while reading about The Language of Adam, and the Guarden of Eden. It says that you can only be in the guarden while in the shape of an animal, and if you eat one of the fruits, your instantly removed and your real form from now on becomes that animal. Now, what if a Bjornaer eats of the fruit? How does this work with the rule of true nature?
E.
The limit of essential nature is a Hermetic limit. The Divine is certainly not bound by it.
Hey, Ferretz, can I suggest that you edit the title of this thread, or perhaps your first post, to indicate that there's a spoiler? I may be off base on this, but if I were going to introduce this to my saga, what you're asking about is something that I wouldn't want my players to read in passing, and it might be better to err on the side of caution.
I'll address your question in another post.
Yes, it's a limit, but the Bjornaer breaks this limit. When the Bjornaer becomes the heartbeast, he really is an animal, and no magic can see through it. He changes his essential nature. A Bjornaer is, as I understand it, as much human as animal. Could he just shake off the result of eating a fruit?
E.
Awesome! I'm really glad you're enjoying it so much.
I'd suggest the Bjornaer can still change into her human form. The stricture that you remain in the shape you were when you ate it is a side effect of convincing the guardians that you are that type of animal. It means that you remain that animal when you leave. Bjornaers can change into humans as an inherent power, so they can still do so.
What do you think, though? I mean, if eating the fruit signifies the Fall of (Insert Species of Beast Here), what should the consequences be for the Bjornaer and others of her kind? I wrote that chapter like "this is the way things really are," but I'd rather you treated it like "here's a version of the Garden you can use." It's fun just to imagine the possibilities, and I hope that when I see it being used in a saga that there will always be some surprises, because it's such a sweepingly huge idea for a story.
Well, that was one of the things I really liked about the book, is that it gives choices. And I really liked how Caine turned out. Making him a vampire is a bit overdone. I really look forward to roleplaying Caine in my campaign, as I want to combine all three of the ways to learn Adamic. I also think this ancient magic is perfectly suited for my Bjornaer-focused campaign.
It's an interesting question. If a whole species fall, what happens to Bjornaers of that species? Does this mean that animals of this species have souls? What happens to the soul/spirit balance in a Bjornaer then? I have to think on this...
E.
Thanks to Erik for giving us the Garden of Eden!! I can only second Ferretz's admiration of this mystery and of the take on Caine also!
As a sidenote I wondered about something similar to Ferretz. As is you can only enter (sneak) into Eden in the guise of an animal, but your Gift doesn't work and magic items that recast at sunset/dawn to have a constant effect fail. In that case I guess the only way to get there and have enough time to, spending a season at least, to learn the Adamite language from the animals there would require you to use a MuCo ritual to change into an animal for a Year (as anything less is a month at maximum and thus to little to learn much) - disregarding those Bjornaer magi...
I like the idea that this question is kept vague in the book. Discussing however might be very interesting. First, being human by birth you are already party to the Original Sin, so I wonder if this constitutes as fall as such? Secondly that all the other animals of the same type are removed from Eden doesn't necessarily mean that they Fall does it? They didn't eat from the 'forbidden fruit' and even if they did you might consider whether they can actually Fall at all? Whether this is without their capacity and something connected to the nature of Humans (who did take a special place even before the Original Sin)? In any instance, if you decide they could and if the fruit would give them the same consciousness bestowed on Adam and Eve when they ate it, then such an event would definitely have an important impact on the setting, wouldn't it?
The explaination of constant duration enchantments does not say that they recast at sunrise and sunset. The description says that duration sun 2 uses per day and environmental trigger is how you determine the level for the effect.
My bad - I just reread the Adamite chapter in Ancient Magic and realised I missed a very crucial 'besides' in the text on page 20, which makes a mockery of my point.
Still it limits the magic that'll get you in to Eden to either a Year ritual or a magic item. This is no complaint at all - in fact maybe the opposite! - but can anyone think of other ways to remain an animal for enough time to learn what you need (disregarding joining House Bjornaer, succesfully awake your heartbeast and stroll in like the snake you are... whoops.. all that trouble and your heartbeast is banned.. tough luck!) ?
There's the shapeshifter virtue
If you're a holy magus you could do it with duration fast.
The easiest way to make an enchanted device is with the duration limitation. (probably easier to create than a spell).
You could make a deal with some supernatural power to change you for a period of time.
The faerie magic duration of until seems like it would be extremley appropriate (duration year and a day would be a less useful choice but still better than year).
Of course the real question is why you are bothering to learn it from the animals in the garden rather than from the angels outside of it. A targeted intellego mentem spell to pull the knowlege out of the angel accompanied by a muto mentem to allow your brain to hold a perfect memory and a creo mentem to periodically refresh the memory as you study it in later seasons and you should be in the clear. (As far as learning the language goes at least. Doubtless there's lots of stories that could be built out of having shown sufficent hubris to asault Angels with brain sucking rays.)
The PCs get struck by brain-sucking rays from Infernalists ,
who not only take all the knowledge , they PeMe you to forget you ever knew it.
Basically a lot of ideas, which however are not avaiable to the average magus without making another story out of it (great!).
Then it might be better to stick to a forbidden fruit or two! 
My thoughts weren't in regards to the best or most bothersome way to go about it - it was only caused by the speculation of how this one could be handled. If I ever introduce this secret it'll be up to my players whether they end up prefering studying dead languages by piecemeal, by sneaking into other people's (Gods') garden and stealing fruit, by tracking down a notrious murderer or suck the brains of a flamesword wielding cherubim....! 
Hee hee, angel-brain sucking magi rays, I love it.
ADMIT it - it was one of those things only cut in the very last editing!!! 
OK, some thoughts.
That being said, I could very well see some Bjornaer magus with Wizard Wars on his head hide out in the Garden. Great Beasts might be there, too.
And just to rain on your parade 
, I don't think that "angel-brain sucking magi rays" would work, due to the way angels (and demons) intrinsically understand things rather than rely on reflection and knowledge.
Hmmm..
Notice that in my original plan there is a muto mentem spell functioning on the magus at the time of casting to allow him or her to know and retain all of the language for the duration of the spell. Your objection means that the muto mentem spell needs more finesse.
Of course it might then be required that this sort of a mentem spell be running in order to access the memories.
So the new plan is.
develop an angel-y brain spell with a duration of at least moon and an angely brain information retreval spell.
Cast spells on the guardian of the garden with sufficient penetration to ge tthe goods.
Go home and spend the next month or more verbally translating a beastiary, some of the gospels and a text on magic theory to your familiar. Be certain that the familiar follows along with the text while you are speaking.
Learn adamic from your familiar's memories.
Step one is clearly the hardest (and may be impossible if the understanding is not in the mind of the angel).
I agree. Angels are pure Intellect, so you would need to directly target their essence (ie, start stripping most/all Divine Might) before they lost any knowledge.
You don't want to delete the file, just make a copy for your own purposes.
There's no file, it's all in hardware, including a network connection to God. 
At best, you'll copy the driver, but it won't do you much good since you're not even running the same OS.
I hate to point this out, because I'm really curious to see how this would work out in game, but I was careful not to give the guardians a score in Dead Language (Adamic), specifically because I figured they don't know it. I wrote in that they can understand it, but I thought that only beings who are fluent in it have the Ability, and can thus teach it to others. If the Guardians of Eden speak Adamic, you could reason that any angel speaks Adamic-- or any demon for that matter. I figure they can understand any form of intelligent speech, but that it's because of a supernatural effect rather than knowledge. I suspect linguistic things like language and nicknames and so on probably seem odd and alien to angels, who have no need of them.
I also really like the idea of them forbidding the Get of Octavius or whoever, by the way. I wonder if it would ruin some of the magic if when the characters first arrive they are greeted with a list of people they don't know who are henceforth forbidden to enter the Garden, though. Then again, it might be interesting for them to try and figure out what happened to these other seekers, perhaps even track them down to find out what they learned, and also demonstrates to the characters that there is a way in, if they can discover it.
Or, what if there were another species of animal listed as forbidden entry, like unicorns? That might be a cool discovery: unicorns were banned from Eden because they tasted the fruit of the Tree of Life many years ago, and now cannot be found anywhere in the Garden.