"It's true, even a few hundred years, truths become memories lost to the generations." Istredd's lifespan will be long, hundreds of those years himself, but he knows that even since Stregobor's lifetime, so many things have changed. The man himself, not so much, but the world will always keep spinning, for better or for worse. Maybe there is no point to him putting all of this information down, but he's going to do it anyway.

"You could always try it out, see how it goes." Other people have tried, she might find it interesting. "Yes, it stays there. The Horizon isn't a real place, at least not in terms of being able to transfer to this plane of existence. It's a psychic plane." There are times when psychic planes can be transferred to reality, or at least theoretically it's possible, but for Istredd it is very simple to separate the two.

"Everything we create there is in our minds. The crater around the Singularity, the giant rock that exists both here and in the Horizon, it kills natives when they try to go into it. When we walk into the crater, we go to the Horizon." So the crater may be the closest thing to a physical representation of the Horizon, but it still doesn't make it real.