[Tyabann]

Originally Posted by Kogetsu Shirogane

Disappearance has a rather nasty one which basically makes Kyon's entire existence afterwards questionable.

Spoiler for ... I'm not even sure why I'm putting this in spoiler tags...:

The scene features Ryoko going in to kill Kyon after non-fatally stabbing him. However, she is stopped by an alien version of Yuki before she can reach him. This Yuki was brought from the future by Kyon and the younger version of Mikuru to save Kyon.

Wait, did I say what I think I did? "This Yuki was brought from the future by Kyon... to save Kyon?"

There is absolutely no way that Kyon could have been able to arrange for that to happen if he was already dead for months. If he had managed to survive somehow, he still wouldn't be in a world where Yuki and Mikuru were the alien and time traveler we know and love. Even worse, Yuki would probably be so shaken by the whole act that she'd try to avoid him altogether, and an earlier point in the story shows that Mikuru wouldn't believe a word he said. Plus there's the whole fact that there would be two different Kyons in the same point in time.

If you have an explanation for this instance, I'd really love to hear it. This isn't sarcasm, I truly do wish for an explanation to this situation, as it's the one moment in Disappearance I've never really understood.

Did you read Vol. 7?

It's a predestination paradox, or a casual loop or sorts.

Kyon remembers hearing his own voice (as well as the voices of Yuki and Mikuru) at the point where he passes out, therefore he knows that he has to go back in time to save himself, and bring Yuki and Mikuru with him.

In the prologue of Vol. 7, he does just that, closing the loop.

It's a bit confusing, but it's not a universe-shattering paradox.