Thanks for making this linkpost, Evelyn! I did have some thoughts on this episode, which I'll split into separate comments so it's easier to keep discussion organised. (A basic point is that the episode was really interesting, and I'd recommend others listen as well.)

A bundle of connected quibbles: 

• Ajeya seems to use the term "existential risk" when meaning just "extinction risk"
• She seems to imply totalism is necessary for longtermism
• She seems to imply longtermism is only/necessarily focused on existential risk reduction
• (And I disagree with those things.)

An illustrative quote from Ajeya:

I think I would characterise the longtermist camp as the camp that wants to go all the way with buying into the total view — which says that creating new people is good — and then take that to its logical conclusion, which says that bigger worlds are better, bigger worlds full of people living happy lives are better — and then take that to its logical conclusion, which basically says that because the potential for really huge populations is so much greater in the future — particularly with the opportunity for space colonisation — we should focus almost all of our energies on preserving the option of having that large future. So, we should be focusing on reducing existential risks.

But "existential risks" includes not just extinction risk but also includes risks of unrecoverable collapse, unrecoverable dystopia, and some (but not all) s-risks/suffering catastrophes. (See here.) 

And my understanding is that, if we condition on rejecting the totalism: 

• Risk of extinction does becomes way less important
  • Though it'd still matter due to its effects on the present generation
• Risk of unrecoverable collapse probably becomes way less important (though this is a bit less clear)
• Risk of unrecoverable dystopia and s-risks still retain much of their importance

(See here for some discussion relevant to those points.)

So one can reasonably be a non-totalist yet still prioritise reducing existential risk - especially risk of unrecoverable dystopias. 

Relatedly, a fair number of longtermists are suffering-focused and/or prioritise s-risk reduction, sometimes precisely because they reject the idea that making more happy beings is good but do think making more suffering beings is bad.

Finally, one can be a longtermist without prioritising reducing either reduction of extinction risk or reducing of other existential risks. In particular, one could prioritise work on what I'm inclined to call "non-existential trajectory changes". From a prior post of mine:

But what if some of humanity’s long-term potential is destroyed, but not the vast majority of it? Given Ord and Bostrom’s definitions, I think that the risk of that should not be called an existential risk, and that its occurrence should not be called an existential catastrophe. Instead, I’d put such possibilities alongside existential catastrophes in the broader category of things that could cause “Persistent trajectory changes”. More specifically, I’d put them in a category I’ll term in an upcoming post “non-existential trajectory changes”. (Note that “non-existential” does not mean “not important”.)

(Relatedly, my impression from a couple videos or podcasts is that Will MacAskill is currently interested in thinking more about a broad set of trajectory changes longtermists could try to cause/prevent, including but not limited to existential catastrophes.)

I expect Ajeya knows all these things. And I think it's reasonable for a person to think that extinction risks are far more important than other existential risks, that the strongest argument for longtermism rests on totalism, and that longtermists should only/almost only prioritise existential/extinction risk reduction. (My own views are probably more moderate versions of those stances.) But it seems to me that it's valuable to not imply that those things are necessarily true or true by definition. 

(Though it's of course easy to state things in ways that are less than perfectly accurate or nuanced when speaking in an interview rather than producing edited, written content. And I did find a lot of the rest of that section of the interview quite interesting and useful.)

Is eventually expanding beyond our solar system necessary for achieving a long period with very low extinction risk?

As part of the discussion of "Effective size of the long-term future", Ajeya and Rob discussed the barriers to and likelihood of various forms of space colonisation. I found this quite interesting. 

During that section, I got the impression that Ajeya was implicitly thinking that a stable, low-extinction-risk future would require some kind of expansion beyond our solar system. (Though I don't think she said that explicitly, so maybe I'm making a faulty inference. Perhaps what she actually had in mind was just that such expansion could be one way to get a stable, low-extinction-risk future, such that the likelihood of such expansion was one important question in determining whether we can get such a future, and a good question to start with.)

If she does indeed think that, that seems a bit surprising to me. I haven't really thought about this before, but I think I'd guess that we could have a stable, low-extinction-risk future - for, let's says, hundreds of millions of years - without expanding beyond our solar system. Such expansion could of course help[1], both because it creates "backups" and because there are certain astronomical extinction events that would by default happen eventually to Earth/our solar system. But it seems to me plausible that the right kind of improved technologies and institutions would allow us to reduce extinction risks to negligible levels just on Earth for hundreds of millions of years. 

But I've never really directly thought about this question before, so I could definitely be wrong. If anyone happens to have thoughts on this, I'd be interested to hear them.

[1] I'm not saying it'd definitely help - there are ways it could be net negative. And I'm definitely not saying that trying to advance expansion beyond our solar system is an efficient way to reduce extinction risk.

In my view, the AI timelines work is exactly the kind of research longtermists should do more of to persuade those more skeptical, and test their own assumptions.

Another is Christian Tarsney's "The Epistemic Challenge to Longtermism".

What I'd like to see next are grounded estimates of the causal effects of longtermist interventions, like research and policy, and including risks of backfire (e.g. accelerating AI development).

The sections "Biggest challenges with writing big reports" and "What it’s like working at Open Phil" were interesting and relatable

A lot of what was said in these sections aligned quite a bit with my own experiences from researching/writing about EA topics, both as part of EA orgs and independently. 

For example, Ajeya said:

One thing that’s really tough is that academic fields that have been around for a while have an intuition or an aesthetic that they pass on to new members about, what’s a unit of publishable work? It’s sometimes called a ‘publon’. What kind of result is big enough? What kind of argument is compelling enough and complete enough that you can package it into a paper and publish it? And I think with the work that we’re trying to do — partly because it’s new, and partly because of the nature of the work itself — it’s much less clear what a publishable unit is, or when you’re done. And you almost always find yourself in a situation where there’s a lot more research you could do than you assumed naively, going in. And it’s not always a bad thing.

It’s not always you’re being inefficient or you’re going down rabbit holes, if you choose to do that research and just end up doing a much bigger project than you thought you were going to do. I think this was the case with all of the timelines work that we did at Open Phil. My report and then other reports. It was always the case that we came in, we thought, I thought I would do a more simple evaluation of arguments made by our technical advisors, but then complications came up. And then it just became a much longer project. And I don’t regret most of that. So it’s not as simple as saying, just really force yourself to guess at the outset how much time you want to spend on it and just spend that time. But at the same time, there definitely are rabbit holes, and there definitely are things you can do that eat up a bunch of time without giving you much epistemic value. So standards for that seemed like a big, difficult issue with this work.

I think most of the EA-related things I've started looking into and writing up, except those that I deprioritised very early on, ending up growing and spawning spinoff tangent docs/posts. And then those spinoffs often ended up spawning their own spinoffs, and so on. And I think this was usually actually productive, and sometimes the spinoffs were more valuable than the original thing, but it definitely meant a lot of missed deadlines, changed plans, and uncertainties about when to just declare something finished and move on.

I don't have a lot of experience with research/writing on non EA-related topics, so maybe this is just a matter of my own (perhaps flawed) approach, or maybe it's just fairly normal. (One thing that comes to mind here is that - if I recall correctly - Joe Henrich says in his newest book, The WEIRDest People in the World, that his previous book - Secret of Our Success - was all basically just meant to be introductory chapters to WEIRDest People. And the prior book is itself quite long and quite fascinating!) 

But I did do ~0.5FTE years of academic psychology research during my Honours year. There I came up with the question and basic design before even starting, and the final product really had stuck pretty closely to that, and on schedule, with no tangents. So there's at least weak evidence that my more recent tangent-heavy approach (which I think I actually endorse) isn't just an approach I'd adopt even in more established fields. 

A few other things Ajeya said in those sections that resonated with me:

So a lot of the feeling of collaboration and teamyness and collegiality is partly driven by like, does each part of this super siloed organisation have its own critical mass.

[...]

And then [in terms of what I dislike about my job], it comes back to the thing I was saying about how it’s a pretty siloed organisation. So each particular team is quite small, and then within each team, people are spread thin. So there’s one person thinking about timelines and there’s one person thinking about biosecurity, and it means the collaboration you can get from your colleagues — and even the feeling of team and the encouragement you can get from your colleagues — is more limited. Because they don’t have their head in what you’re up to. And it’s very hard for them to get their head in what you’re up to. And so people often find that people don’t read their reports that they worked really hard on as much as they would like, except for their manager or a small set of decision makers who are looking to read that thing.

And so I think that can be disheartening. 

It was interesting - and sort of nice, in a weird way! - to hear that even someone with a relatively senior role at one of the most prominent and well-resourced EA orgs has those experiences and perceptions.

(To be clear, I've overall been very happy with the EA-related roles I've worked in! Ajeya also talked about a bunch of stuff about her job that's really positive and that also resonated with me.)

The doomsday argument, the self-sampling assumption (SSA), and the self-indication assumption (SIA)

The interview contained an interesting discussion of those ideas. I was surprised to find that, during that discussion, I felt like I actually understood what the ideas of SSA and SIA were, and why that mattered. (Whereas there've been a few previous times when I tried to learn about those things, but always ended up mostly still feeling confused. That said, it's very possible I currently just have an illusion of understanding.)

While listening, I felt like maybe that section of the interview could be summarised as follows (though note that I may be misunderstanding things, such that this summary might be misleading):

"We seem to exist 'early' in the sequence of possible humans. We're more likely to observe that if the sequence of possible humans will actually be cut off relatively early than if more of the sequence will occur. This should update us towards thinking the sequence will be cut off relatively early - i.e., towards thinking there will be relatively few future generations. This is how the SSA leads to the doomsday argument.

But, we also just seem to exist at all. And we're more likely to observe that (rather than observing nothing at all) the more people will exist in total - i.e., the more of the sequence of possible humans will occur. This should update us towards thinking the sequence won't be cut off relatively early. This is how the SIA pushes against the doomsday argument.

Those two updates might roughly cancel out [I'm not actually sure if they're meant to exactly, roughly, or only very roughly cancel out]. Thus, these very abstract considerations have relatively little bearing on how large we should estimate the future will be."

(I'd be interested in people's thoughts on whether my attempted summary seems accurate, as well as on whether it seems relatively clear and easy to follow.)

I like Ajeya's metaphor of different "sects" of the EA movement being different stops on the "train to crazy town":

So, you can think about the longtermist team as trying to be the best utilitarian philosophers they can be, and trying to philosophy their way into the best goals, and win that way. Where at least moderately good execution on these goals that were identified as good (with a lot of philosophical work) is the bet they’re making, the way they’re trying to win and make their mark on the world. And then the near-termist team is trying to be the best utilitarian economists they can be, trying to be rigorous, and empirical, and quantitative, and smart. And trying to moneyball regular philanthropy, sort of. And they see their competitive advantage as being the economist-y thinking as opposed to the philosopher-y thinking.

And so when the philosopher takes you to a very weird unintuitive place — and, furthermore, wants you to give up all of the other goals that on other ways of thinking about the world that aren’t philosophical seem like they’re worth pursuing — they’re just like, stop… I sometimes think of it as a train going to crazy town, and the near-termist side is like, I’m going to get off the train before we get to the point where all we’re focusing on is existential risk because of the astronomical waste argument. And then the longtermist side stays on the train, and there may be further stops.

The idea of neartermism and longtermism reflecting economist-like and philosopher-like ways of thinking struck a chord with me. I feel as if there are conflicting parts of me that want to follow different approaches to saving the world.

I'm not finished yet with the whole episode, but I didn't understand the part about fairness agreements and the veil of ignorance that Rob and Ajeya were talking about as a way to figure out how much money to allocate per worldview. This was the part from 00:27:50 to 00:41:05.  I think I understood the outlier opportunities principle though.

I've re-read the transcript once to try and understand it more but I still don't. I also googled about the Veil of Ignorance, and it started to make more sense, but I still don't understand the fairness agreements part. Is there a different article that explains what Ajeya meant by that? Or can someone explain it in a better way? Thanks!

I really enjoyed this podcast. But regarding space colonization, I do not think that uploading humans to computers is the only alternative to avoid transporting human colonies in space ships. For instance, we could send facilities for producing nutrition, oxygen and human artificial wombs there, plus two tiny test tubes of undamaged egg and sperm cells. Of course, once synthetic biology gives us the ability to create cells ourselves, we can also upload the human (epi)genome to a storage medium and synthetize the DNA and zygotes on the new planet.