Which is what makes the library of Jyggalag and the Prophetic Deduction unique.

Jyggalag is the opposite of Sheogorath because logic is the opposite of the illogical. Jyggalag is perfectly rational, while Sheogorath cannot be rational to save his life. Jyggalag's emotionless hyper-logic may be insane by some definitions, but it is clearly the opposite of the extremely emotional and irrational Sheogorath.

They're blank. As are all the books of your avatar's library. History distorted with an agenda.

More precisely, what MK said in the WWPD? thread. I say this with all the smiles of a four headed octonoggin.

Perfect rationality does not exist.

Sheogorath is rational enough to use the CoC and break the Greymarch cycle. Rational enough to sabotage his bet with Azura, rational enough to know his effect on mortals and take delight in it.

But Sheo isn't "absolutely mad," because such a thing doesn't exist. Nor is Boethiah "absolutely murderous," nor Molag Bal "absolutely raqey."

The problem with Jyg, from a conceptual viewpoint, is that his presence in the lore has caused this silly absolutist dichotomy.

Herma Mora is "absolutely knowledgable." So there.

Boogum devile

Absolutely unknowable too.

All those books in the vast shelves of Apocrypha?

Empty.

Yet one still reads them. Just like how the Oghma Infinium bestows power to you despite the fact that it is written in an unrecognisable arcane script.

The carrot is just a carrot. It's the dangling-on-string in front of your face that works the real magic.

Wait for it... wait for it... He's off in the Plane of Order... gettin' jyggy wit' it.

Nana na na nana

Load of old tosh.

To continue my point. We have a source that indicates Sheogorath was born when the mortal plane was created.

Contemporary sources indicate that his [Sheogoraths] roots are in Aldmeri creation stories; therein, he is 'born' when Lorkhan's divine spark is removed.

Now Sheogorath wasn't the only god born in this moment. The creation of the Mortal plane upset allot of things. I'll be using this to argue that the creation of the mortal plane made the world fundamentally unpredictable.

As the process of subcreation continued, both Anu and Padhome awakened. For to see your antithesis is to finally awaken. Each gave birth to their souls, Auriel and Sithis, and these souls regarded the Aurbis each in their own part, and from this came the etada, the original patterns. These etada eventually congealed.

(...)

As time allowed more and more patterns to individualize, Lorkhan watched the Aurbis shape itself and grew equally delighted and tired with each new shaping.

(....)

Now Lorkhan had by at this point seen everything there was to see, and could accept none of it. Here were the etada with their magic and their voids and everything in between and he yearned for the return to flux but at the same time he could not bear to lose his identity.

(...)

All of these representations [of chim] possess an innate and constant aspect of transformation.

In simple terms, the world had become predictable. Lorkhan wanted to return to the flux. The flux was in constant change. Always creating new patterns, that don't get a chance to congeal because they fade out. That is, the mortal plane was that return to the flux, we are those patterns and we don't congeal, we die.

Finally the Chancellor of Exactitude appeared, and he was perfect to look upon from every angle. Vivec understood the challenge immediately and said:

'Certitude is for the puzzle-box logicians and girls of white glamour who harbor it on their own time. I am a letter written in uncertainty.'

(...)

This magic I give to you: the world you will rule is only an intermittent hope and you must be the letter written in uncertainty.'

We haven't quite established that this flux is unpredictable. Even a flux may follow a pattern. The above however indicates that there elements in the world which are truly unpredictable. Also consider the effects of the Dragon Break on the Elderscrolls. When all these gods are stomping around, they can't describe what is happening. They can't transcribe letters of uncertainty.

So what I reckon is that with the creation of Mundus the Aurbis changed from predictable to unpredictable. The concept that Jyg embodies simply no longer exists, rendering him powerless beyond anything but the madness of a mad god.

edit:

For the sake of intellectual honesty I should also add that http://www.imperial-library.info/node/2234.

I've been wondering. Is the curse that the Daedric Princes cast on Jyggalag related to creation? Lorkhan wanted to create the mortal plane to defy predictability, which is Jyggalag's sphere. So could one say that Lorkhan was the prince that cursed Jyggalag?

I wonder if Jyggalag predicted himself being overthrown and the Greymarch cycle. Maybe it was a feedback loop where he only continued on his path because the calculations said he would. If he could change his mind, he could've avoided the curse. He screwed up because the calculations said he would screw up because he wouldn't stop screwing up because the calculations said he'd screw up. He could've changed his mind, but he didn't want to, and thus his calculated prophecies predicted an inevitable end because there was no way he could actually realize how to prevent it. But the Champion of Cyrodill taught him something. Despite being told that he will fail, he succeeded. Jyggalag has learned that his calculations can be made in error, and that one needs not to follow them. He has freed himself from the shackles of fulfilling destiny for the sole purpose of fulfilling destiny, and for the first time in his existence he has true free will. Jyggalag no longer walks into destruction for the sole sake of fulfilling his purpose. He learns how acting against your nature can be good, how Sheogorath the mad made a rational plan against his sphere and succeeded.

I doubt that's what he meant. The Interviews suggests that Jyggalag is out there somewhere, and Sheogorath's dialogue also mentions he knew Martin Septim and talked about a fox and a severed head.

Look at this guy, with his sources. I don't care much for AEplex's (AE-Ayleid?) sources. Not the real ones, anyway. He's constantly changing the walls in his cell, so I might as well look to my own walls.

If only we could have had this much discussion in CHIDAEDROTH ET JYG AE SHEO.

I've just given up on that and Councillum Chorrol as well. Can't be effed to do anything because nobody else does anything.

Well, Chorrol's been resolved. Divine Mystery, te he.

I'm still operating under the impression that he somehow merged with Peryite, with credence from the Summoning Day Letters and the Skyrim loading screens for Peryite where he is now listed generally as the Prince of order.

I'm not accepting that he just got stuck back in Sheo for another round; this would cause the events of SI to be ultimately inconsequential and produce nothing really new (apart from a nuance in Sheo). This is the same reason I reject the "SI was just Sheo driving the character insane" theory, because it similarly makes everything inconsequential and therefore boring.

Jyg is to Aka as Sheo is to Lorkhan, at least that's the way I see it; echoes/effects in Oblivion or somesuch.

Do we know who wrote the Summoning Day Letters?

Nope. And every person of import I've talked to says they don't know and didn't do it, so I'm 99% certain they're not official. Interesting and well done, just not official. So I'd talk from their perspective, but not treat them as an authority.

News to me. I'm going to have to reread then. It would be incredible if they were done by a fan though. Since, well, they were released just days before Skyrim, and seemed to foretell the plot (that is, looking back on them).