Yes, this topic contains CHIM, but please be polite when discussing it, I have had enough of people saying "YEAH I KNOW WHAT CHIM IS BUT I WON'T TELL YOU 'CAUSE I'M COOLER THAN YOU!"
I have put my old post in spoiler tags, because it got confusing when I started updating it with new realizations. Here's the remade one (note that this is my theory, nothing else):
When one achieves CHIM, one gets the ability to perceive everything, everywhere all the time. But to do this, you would need to be on a multidimensional timeline, with infinite possibilities that you can choose from and jump inbetween. This basically means that you pick and choose what you want to do from infinite possibilities: in your mind, this is ultimate power. BUT! There's a big freakin' BUT here: everyone else lives on a linear timeline. Evidence for this? Akatosh. The dragon would never have to break if there didn't have to be one single linear timeline that the whole world perceived.
Now, onto the next assumption based on this: Vivec is not a god. Vivec runs around in his infinite choices, but he has no idea that it isn't the real world he's in. A god can see all these parallel timelines as well, but a god can also identify the one that is reality, as determined by Akatosh, the true time god. The most telling example for this is that Vivec can perceive time wherever he wants, but only Akatosh (and possibly other gods) has control over the linear timeline.
The result of this, when looking at Vivec from the real, linear, timeline, is that Vivec is now completely random. He does not have the ability to focus on true time, so somebody who does not have the ability to perceive the endless parallel timelines will just see the linear rendering of Vivec's actions: which is nonsense and random. The only time he can appear coherent is when a real god finds the timeline Vivec is currently existing in, and nailing it down as his true timeline. Then he is just a mortal again. Evidence for gods being able to nail Vivec's timeline down, I find in the Trial of Vivec. In the beginning, Vivec is very cryptic, bordering on unintelligeble, but when Sheogorath has appeared, Vivec becomes more and more "human", even resorting to threats and quite unsophisticated language, saying things like "Not only are you wrong, but you have proven why scholars must enjoy empty beds. To all of you, drop this matter. Now."
So in short, CHIM is endless power for the one who acheives it, and nothing at all for everyone else.
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Old post here:
My theory in all this is that Vivec experiences everything, everywhere at the same time because of his CHIM, but a regular person can only observe one of these eventualities. Thus, anything can occur when perceiving Vivec, because the person perceiving him can't decide by himself which event to watch. It's all random. So the above quote might not have made perfect sense to the people who existed in the same fold of reality at the Trial of Vivec, but in another fold, it would appear like he said it completely "non-strangely". Of course, only a god could have chosen by himself to tune in to just this one "making-sense" fold. A Dragon-break would arguably mash all these eventualities into one, making Vivecs timeline in to a logical string of actions.
This also raises the question of whether Vivec is still a person, or even a god. My view on the subject is that Vivec has become much like the laws of physics, which is the only thing that matches the same criteria of being everywhere at once all the time. One could argue that "no, gods match that criteria as well", but I think not. I think gods have the ability to exist in one fold of reality if they wish, whereas Vivec exists in all of them at the same time, and is not able to decide which action is to be taken where. And, just as with the laws of physics, only people with the correct sense (read: gods) can perceive what Vivec is actually doing, just as only a person with eyes can see.
I know this is a touchy subject to lore-buffs out there, but if your opinion differs from mine, then please state your own opinion and let's have a discussion, not a flame war (my last topic regarding CHIM was rather unpleasant at times).
EDIT: From this one might conclude that he is (just as he says about him being "the middle air") not a god, and not a mortal, but something in between.
EDIT 2: And as for the rest of the trials making more sense, I think it might be because the presence of gods such as Azura and Sheogorath "centered Vivec's timeline", so to speak. (and while at it, possibly influencing him in other ways (mostly Sheogorath who had a beef with the Tribunal)).
EDIT 3: Ok, so that previous edit started a new theory: Vivec exists on a multidimensional timeline, you might compare it to the timeline at the end of Daggerfall, where the dragon broke and the multidimensional timeline was merged into a linear one. I think the same is true with Vivec: A real god can focus his multidimensional timeline into a linear one, clearly perceivable by mortals. A real god can also focus another, lesser being's, timeline into a linear one, such as Vivec's. This doesn't mean that Vivec doesn't know what he's doing, it's just that he exists in a different time-format than mortals, and thus, the linear rendering of his timeline is random, because he doesn't have the power to control it like real gods do (as in: he can perceive time freely, but he can't alter the linear timeline of the world like Akatosh and such great gods). Pretty deep, eh?[/color]