"The height or the... other parts?"

"The height, the glass, the appliances - I probably haven't even noticed everything yet, but it's very impressive."

"That. Yeah. It's mostly not even magic." They consider saying something, and then say something else instead. "Best world I've ever been to, this is."

"I've heard that," he nods. "I only have the one other to compare it to, personally, at least as far as places we could live go, and I'm not sure they're similar enough to compare, really."

"No? I guess maybe it's pointless to ask how they're different, then."

"Well, I did only get here this morning, I also don't know much yet. But you've managed to make the libraries free, and you have enough food to give it away to everyone, but also somehow fresh vegetables are a luxury - I have no idea how you'd wind up with enough food to give it away but no vegetables in springtime, that would never happen at home."

"Wh... oh, it's not no vegetables, it's that food for the deliveries is conjured out of nothing and for some reason that's more efficient if they do big batches rarely so it's mostly shelf-stable. Nothing stopping you from buying vegetables, or so I hear."

"Ah, that makes more sense. We have conjuration too, but it works differently, it wouldn't be remotely possible to feed a city with it - I might do dinner for the building sometime, though."

"Then I bet you'll be popular. Although I don't think the entire building can all eat the same things. Or eat together. Or be polite to each other at the same social get-together."

"Huh. Well, I doubt I'll be around long enough to get that sorted out."

That gets him a knowing nod. "Any idea where you're going afterward?"

"Only part of one - conjuration isn't the only magic I have, and the god I get it from objects to people being imprisoned; the woman at the information booth said the king will probably want to talk to me about helping with some of the other worlds where that's a problem."

"That sounds like the sort of thing he'd do, yeah. I've never been sure if he really hates the hells or just wants to be popular with people who do."

"Who's that?"

"The people who hate hells? There are a lot of them, at least around here. This whole place is about hating hells."

"That's not bad, then. There's certainly worse things than wanting to be popular with the people you rule."

"Probably true. Well. How about I give you my email and then you'll have someone local to ask if anything comes up while you're staying here."

"I'd appreciate that."

They can do that.

They'll be out here a while longer but they don't have much else to say unless he does.

He eventually casts another flight spell and spends fifteen minutes swooping around looking at the streets from above before going in.

He stays in for his devotions in the morning, not yet sure he can find his way back without spending magic on it, and then heads down to the lobby to conjure food for the day - it's the same spell to feed a crowd as himself, and better not to waste the extra capacity; he aims for mostly fruit and vegetables and leaves a note saying 'free - magically produced - fades tomorrow morning' on what he doesn't take, and then heads out to find the nearby library he was told about the day before.

The nearby library is near a subway stop and a bus stop. It's several floors tall. There are multiple computers just dedicated to having the catalog open and searchable near the main entrance; there's also a room full of borrowable computers, half of them in use.

There's a cozy room, with every wall lined with shelves of easier novels and guides to dozens of topics all aimed at a lay audience and the center of the room taken up by tables and chairs and reams of loose paper and cups of writing implements waiting on the tables for someone to take them. (Several someones are doing just that.) There are three huge halls of nonfiction on - maybe not every topic in the world, but a credible attempt at that. There's a children's section, all in bright colors, with lots of open spaces and child-sized furniture and puzzles in addition to the short bookshelves; two of the children in there are trying to collaborate on some kind of report about whales and getting into an argument about taxonomy that would probably turn out to have no substance if they had several concepts they do not, at this point, actually have. There's a room dedicated entirely to fantasy, and one dedicated entirely to a genre of novel that almost resembles a sitcom, and one dedicated entirely to religious and uplifting fiction; that's all in addition to the miscellaneous fiction section.

It would seem busy, were it a remotely reasonable size, but as it is it's not all that full. Not at the moment, anyway.

Well, the first thing he's going to do is check his mail.

-no, the first thing he's going to do is stand and ogle for a minute. But after that the first thing he's going to do is check his mail.

He has mail from the king; the timestamp is from early this morning.

Greetings, Traveler Raafi,

I would be very interested in meeting with you to discuss the hells and your god. How about Thursday (the day after tomorrow as of my writing this email) at eleven in the morning at my office on the university campus?

Yeshua, King of New Jerusalem, PhD

He sends an email back confirming, looks up how to get there, and then - how about that other lecture, Theories of Identity and Population Ethics?

In this one, he seems like he's having a lot of fun nerding out about one of his favorite subjects.

There are a number of competing definitions of identity. Most people in the intended target audience, if they haven't thought it through already, default to a definition based on spiritual continuity: each person is a soul, which can change over time and be instantiated in different worlds but cannot stop existing. But that definition is unfalsifiable and not directly observable. If living people didn't have souls, and dead people were only copies of them, how would anyone ever know? These kinds of concerns give rise to other definitions. Maybe it makes sense to define identity based on observable facts about a person: if a newly dead person behaves just like they did when they were alive, remembers the same things they did when they were alive, and feels the same feelings they felt when they were alive, then maybe it doesn't matter if they were copied or teleported or something else. But they aren't identical; they see new things, and that makes them feel new things and do new things and make new memories. Over time they forget things. Over time they can change everything about themselves. An implication of defining identity based on specific traits is that this constitutes becoming a different person. But which parts constitute that? Does every change make someone a new person? Does having one thing in common with someone make you the same person? Most people reject both of those options. And he'll go into detail on some of the more popular specific definitions of identity, but first...

Why is this relevant to population ethics? In some cases it isn't; under, for example, total hedonic utilitarianism, it doesn't particularly matter if there are two people who are happy for a thousand years each, or one person who is happy for two thousand years. But under the person-affecting view, it's wrong to make someone less happy, but not wrong to cause a less happy person to come into existence instead of a happier one; it's therefore essential to define identity somehow. And under the maximin principle, the welfare of the worst-off person is the priority - so under certain interpretations, it matters which experiences belong to the same person. This is even a problem for all of ethics, not just population ethics - some definitions of personhood allow for one body and soul to have multiple persons simultaneously, making it hard if not impossible to distinguish between someone consenting to experience some pain for a later reward, and someone choosing to hurt someone else for personal gain - but this course is only about population ethics.

After the introduction, the rest of the course is organized around a few specific definitions of identity and personhood, going into detail about how each one would interact with each of a few specific ethical theories in a few example scenarios.