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All of TobyC's Comments + Replies

An Intro to Anthropic Reasoning using the 'Boy or Girl Paradox' as a toy example
TobyC10

That's a nice way of looking at it. It's still not very clear to me why the SIA approach of apportioning among possible observers is something you should want to do. But it definitely feels useful to know that that's one way of interpreting what SIA is saying.

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1antanaclasis
From the SIA viewpoint the anthropic update process is essentially just a prior and an update. You start with a prior on each hypothesis (possible universe) and then update by weighting each by how many observers in your epistemic situation each universe has. This perspective sees the equalization of “anthropic probability mass” between possible universes prior to apportionment as an unnecessary distortion of the process: after all, “why would you give a hypothesis an artificial boost in likelihood just because it posits fewer observers than other hypotheses”. Of course, this is just the flip side of what SSA sees as an unnecessary distortion in the other direction. “Why would you give a hypothesis an artificial boost due to positing more observers” it says. And here we get back to deep-seated differences in what people consider the intuitive way of doing things that underlie the whole disagreement over different anthropic methods.
An Intro to Anthropic Reasoning using the 'Boy or Girl Paradox' as a toy example
TobyC20

That's a fair point! I have probably undersold the idea here. I've edited the post to add a comment about this.

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An Intro to Anthropic Reasoning using the 'Boy or Girl Paradox' as a toy example
TobyC21

You raise lots of good objections there. I think most of them are addressed quite well in the book though. You don't need any money, because it seems to be online for free: https://www.stafforini.com/docs/Parfit%20-%20Reasons%20and%20persons.pdf And if you're short of time it's probably only the last chapter you need to read. I really disagree with the suggestion that there's nothing to learn from ethical philosophy books.

For point 1: Yes you can value other things, but even if people's quality of life is only a part of what you value, the mere-addition pa... (read more)

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2jbash
Quickly, 'cuz I've been spending too much time here lately... One. If my other values actively conflict with having more than a certain given number of people, then they may overwhelm the considerations were talking about here and make them irrelevant. Three. It's not that you can't do it precisely. It's that you're in a state of sin if you try to aggregate or compare them at all, even in the most loose and qualitative way. I'll admit that I sometimes commit that sin, but that's because I don't buy into the whole idea of rigorous ethical philsophy to begin with. And only in extremis; I don't think I'd be willing to commit it enough for that argument to really work for me. Four. I'm not sure what you mean by "distribution of happiness". That makes it sound like there's a bottle of happiness and we're trying to decide who gets to drink how much of it, or how to brew more, or how we can dilute it, or whatever. What I'm getting at is that your happiness and my happiness aren't the same stuff at all; it's more like there's a big heap of random "happinesses", none of them necessarily related to or substitutable for the others at all. Everybody gets one, but it's really hard to say who's getting the better deal. And, all else being equal, I'd rather have them be different from each other than have more identical ones.
An Intro to Anthropic Reasoning using the 'Boy or Girl Paradox' as a toy example
TobyC10

Is that definitely right? I need to have an in-depth read of it, which I won't have time for for a few days, but from a skim it sounds like they admit that FNC also leads to the same conclusions as SIA for the presumptuous philosopher, but then they also argue that isn't as problematic as it seems?

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2rotatingpaguro
I've skimmed the paper and read excerpts, but anyway: I'd describe what Neal does as deconstructing the paradox. So yes, in some sense he's arguing it's not as problematic. That's why I suggested to say that FNC argues to solve the problem, instead of outright saying FNC solves the problem. Saying "We mention it here just as an example of how you might try to give a more solid foundation to the SSA+SIA approach" makes it look like FNC is just that, without further developments, and I was surprised when I gave a look to the paper, which is something I could well not have done if I had even less time.
An Intro to Anthropic Reasoning using the 'Boy or Girl Paradox' as a toy example
TobyC30

Thanks for the comment! That's definitely an important philosophical problem that I very much glossed over in the concluding section.

It's sort of orthogonal to the main point of the post, but I will briefly say this: 10 years ago I would have agreed with your point of view completely. I believed in the slogan you sometimes hear people say: "we're in favour of making people happy, and neutral about making happy people." But now I don't agree with this. The main thing that changed my mind was reading Reasons+Persons, and in particular the "mere-addition para... (read more)

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3jbash
I have probably heard those arguments, but the particular formulation you mention appear to be embedded in a book of ethical philosophy, so I can't check, because I haven't got a lot of time or money for reading whole ethical philosophy books. I think that's a mostly doomed approach that nobody should spend too much time on. I looked at the Wikipedia summary, for whatever that's worth, and here are my standard responses to what's in there: 1. I reject the idea that I only get to assign value to people and their quality of life, and don't get to care about other aspects of the universe in which they're embedded and of their effects on it. I am, if you push the scenario hard enough, literally willing to value maintaining a certain amount of VOID, sort of a "void preserve", if you will, over adding more people. And it gets even hairier if you start asking difficult questions about what counts as a "person" and why. And if you broaden your circle of concern enough, it starts to get hard to explain why you give equal weight to everything inside it. 2. Even if you do restrict yourself only to people, which again I don't, step 1, from A to A+, doesn't exactly assume that you can always add a new group of people without in any way affecting the old ones, but seems to tend to encourage thinking that way, which is not necessarily a win. 3. Step 2, where "total and average happiness increase" from A+ to B-, is the clearest example of how the whole argument requires aggregating happiness... and it's not a valid step. You can't legitimately talk about, let alone compute, "total happiness", "average happiness", "maximum happiness", or indeed ANYTHING that requires you put two or more people's happiness on the same scale. You may not even be able to do it for one person. At MOST you can impose a very weak partial ordering on states of the universe (I think that's the sort of thing Pareto talked about, but again I don't study this stuff...). And such a partial ordering doesn
An Intro to Anthropic Reasoning using the 'Boy or Girl Paradox' as a toy example
TobyC20

I agree that skepticism is appropriate, but I don't think just ignoring anthropic reasoning completely is an answer. If we want to make decisions on an issue where anthropics is relevant, then we have to have a way of coming up with probabilistic estimates about these questions somehow. Whatever framework you use to do that, you will be taking some stance on anthropic reasoning. Once you're dealing with an anthropic question, there is no such thing as a non-anthropic framework that you can fall back on instead (I tried to make that clear in the boy-girl ex... (read more)

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2Dagon
This is probably our crux.   I don't think there are any issues where anthropics are relevant, because I don't think there is any evidence about the underlying distribution which would enable updating based on an anthropic observation.
[Link]: Anthropic shadow, or the dark dusk of disaster
TobyC10

I am struggling to follow this anthropic shadow argument. Perhaps someone can help me see what I am getting wrong.

Suppose that every million years on the dot, some catastrophic event happens with probability P (or fails to happen with probability 1-P). Suppose that if the event happens at one of these times, it destroys all life, permanently, with probability 0.1. Suppose that P is unknown, and we initially adopt a prior for it which is uniform between 0 and 1.

Now suppose that by examining the historical record we can discover exactly how many times the ev... (read more)

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2avturchin
Yes, it seems that self-indication assumption is exactly compensating the anthropic shadow: the stronger is the shadow, the less likely I will be in such a world. However, it works only if worlds with low p and no shadow actually exist somewhere in the multiverse (and in sufficiently large numbers). If there is a universal anthropic shadow, it will still work.