Interesting take, but I'll note that these are not acausal, just indirect-causal.  Voting is a good example - counts are public, so future voters KNOW how many of their fellow citizens take it seriously enough to participate.  

In all of these examples, there is a signaling path to future impact.  Which humans are perhaps over-evolved to focus on.

I disagree. There is no acausal coordination because eg the reasoning "If everyone thought like me, democracy would fall apart" does not actually influence many people's choice, ie they would vote due to various social-emotional factors no matter what that reasoning said. It's just a rationalization.

More precisely, when people say "If everyone thought like me, democracy would fall apart", it's not actually the reasoning that it could be interpreted as, it's a vague emotional appeal to loyalty/the identity of a modern liberal/etc. You can tell because it refers to "everyone" instead of a narrow slice of people, it involves no modelling of the specific counterfactual of MY choice, there's no general understanding of decision theory that would allow this kind of reasoning to happen and any reasonable model of the average person's mind doesn't allow it imo.

Your model is also straining to explain the extra taxes thing. "Voting is normal, paying extra taxes isn't" is much simpler.

In general, I'm wary of attempts to overly steelman the average person's behavior, especially when there's a "cool thing" like decision theory involved. It feels like a Mysterious Answers to Mysterious Questions [LW · GW] kind of thing.

Humans, in the examples provided, are (I think) applying something like the logic "what if everyone did this" to assess the morality of an action. In my experience that is quite a common way of reasoning about morality, it was presented to me as a child as "common sense", and many years later I learned it was a big deal to Kant , https://en.wikipedia.org/wiki/Categorical_imperative (I am really curious if it was already "common sense" before Kant or if he added it to the common sense pile). But all of this is used when discussing the morality of an action.

As I understand it (which I don't) acausal decision theory is aiming to maximise the effectiveness of actions, not assess their morality. I don't know if this drives a wedge into things or not.

The usual story of acausal coordination involves agent P modeling agent Q, and Q modeling P. Put differently, both P and Q model the joint system (P+Q) that has both P and Q in it. But it doesn't have to be (P+Q), it could be some much simpler R instead. I think a more central example of acausal coordination is to simply follow shared ideas.

The unusual character of acausal coordination is caused by cases where R is itself an agent, an adjudicator between P and Q. As a shared idea, it would have instances in minds of both P and Q, and command some influence allowed by P and Q over their actions. It would need to use some sort of functional decision theory to make sense of its situation where it controls the world through causally unrelated actions of P and Q that only have R's algorithm in common behind them.

The adjudicator R doesn't need to be anywhere as complicated as P or Q, in particular it doesn't need to know P or Q in detail. Which makes it much easier for P and Q to know R than to know each other. It's just neither P nor Q that's doing the acausal coordination, it's R instead.

I agree with the general take - my explanation of why people often have pushback to the idea of acausal reasoning is because they never really have cause to actively apply it. In the cases of voting or recycling, the acausal argument naively feels more like post-fact justification than proactive reason to do it if it weren't the norm.

Most of the cases of people doing some things explained by acausal reasoning but not other equally sensible things also requiring acausal justification seem really well-modelled as what they were already going to do without thinking about it too hard. When they think about it too hard is when you end up with a lot of people who actively disagree with that line of thought - and a lot of people I know take that stance, that acausal reasoning isn't valid and so they don't have personal onus to recycle or switch careers to work on effective things (usually because corporations and other entities have more singular weight), but still vote.

Note that, for rational *altruists* (with nothing vastly better to do like alignment), voting can be huge on CDT grounds -- if you actually do the math for a swing state, the leverage per voter is really high.  In fact, I think the logically counterfactual impact-per-voter tends to be lower than the impact calculated by CDT, if the election is very close. 

I like this post and agree that acausal coordination is not weird fringe behavior necessarily. But thinking about it explicitly in the context of making a decision, is. In normal circumstances, we have plenty of non-acausal ways of discussing what's going on, as you discuss. The explicit consideration is something that becomes important only outside the contexts most people act in.

That said, I disagree with the taxes example in particular, on the grounds that that's not how government finances work in a world of fiat currency controlled by said government. Extra taxes paid won't change how much gets spent or on what, it'll just remove money from circulation with possible downstream effects on inflation. Also, in some states in the US (like Massachusetts this year), where the government doesn't control the currency, there are rules that surpluses have to get returned in the form of tax refunds. So any extra state taxes I paid, would just get redistributed across the population in proportion to income.

My intuition for voting is that your political values somehow correlates with your decision whether to vote or not, so although I always vote, I do not mind when other people go like "what's the point of voting?", because it means more political power for people like me, and less power for people like them.

With paying extra taxes, there is no "more power" for the kind of people who would decide to pay more. It all goes to the same budget, governed by the same algorithm. There is no victory for people like me over other kinds of people, if people like me pay extra taxes and the other kinds of people do not. On the other hand, I might donate money to a specific cause (even if the donation is anonymous, so I get no personal benefit from doing that), because that would mean that causes preferred by people like me get extra support.

Also, I think that people exaggerate the difficulty of voting. Especially in cases where it only requires 5 minutes of walk. Please do not tell me that your life is so optimized that taking a 5 minute walk once in a few years would make a visible difference; I am not going to believe that. (You have probably already spent way more time explaining on internet why voting is a complete waste of time, than I have spent actually voting.)

The voting example is one of those interesting cases where I disagree with the reasoning but come to a similar conclusion anyway.

I claim the population of people who justify voting on any formal reasoning basis is at best a rounding error in the general population, and probably is indistinguishable from zero. Instead, the population in general believes one of three things:

1. There is an election, so I vote because I'm a voter.
2. Voting is meaningless anyway, so I don't.
3. Election? What? Who cares?

But it looks to me this is still coordination without sharing any explicit reasoning with each other. The central difference is that group 1 are all rocks with the word "Vote" painted on them, group 2 are all rocks with the word "Don't vote" painted on them, and group 3 are all rocks scattered in the field somewhere rather than being in the game.

As I write this it occurs to me that when discussing acausal coordination or trade we are always showing isolated agents doing explicit computation about each other; does the zero-computation case still qualify? This feels sort of like it would be trivial, in the same way they might "coordinate" on not breaking the speed of light or falling at the acceleration of gravity.

On the other hand, there remains the question of how people came to be divided into groups with different cached answers in the first place. There's definitely a causal explanation for that, it just happens prior to whatever event we are considering. Yet going back to the first hand, the causal circumstances giving rise to differing sets of cached answers can't be different in any fundamental sense from the ones that give differing decision procedures.

Following from that, I feel like the zero-computation case for acausal coordination is real and counts, which appears to me to make the statement much stronger.

A related example I saw somewhere, maybe here on LW: High-ranking politicians like senators don't need to be bribed directly. It is enough that there is an implicit expectation that if you vote in the interests of a big corporation, then you will get highly-paid speaking opportunities from these companies later - completely without any agreements between them, just because such companies will reliably provide such opportunities for such senators.  

Wow, Zvi example is basically what I've been doing recently with hyperbolic discounting too after I've spent a fair amount of time thinking about Joe Carlsmith—Can you control the past. It seems to work. "It gives me a lot of the kind of evidence about my future behavior that I like" is now the dominant reason behind certain decisions.

I fully agree*. I think the reason most people disagree, and thing the post is missing is a big disclaimer about exactly when this applies. It applies if and only if another person is following the same decision procedure to you.

For the recycling case, this is actually common!

For voting, it's common only in certain cases. e.g. here in NZ last election there was a party TOP which I ran this algorithm for, and had this same take re. voting, and thought actually a sizable fraction of the voters (maybe >30% of people who might vote for that party) were probably following the same algorithm. I made my decision based on what I thought the other voters would do, which I thought was that probably somehat fewer would vote for TOP than in the last election (where the party didn't get into parliament), and decided not to vote for TOP. Lo and behold, TOP got around half the votes they did the previous election! (I think this was the correct move because I don't think the number of people following that decision procedure increased)

*except confused by the taxes example?

I got the impression that most justifications for voting and reducing carbon footprint are reasoned from virtue ethics rather than something consequentialist, and that consequentialism is not present at all, e.g

It is a virtuous to be a person who votes. I strive to be a virtuous person, so I shall vote. 

rather than

I’m like the people who share my views in my tendency to vote ... So I should vote, so that we all vote and we all win

See also Newcomblike problems are the norm [LW · GW].

When I discuss this with people, the response is often something like: My value system includes a term for people other than myself - indeed, that's what "morality" is - so it's redundant / double-counting to posit that I should value others' well-being also as an acausal "means" to achieving my own ends. However, I get the sense that this disagreement is purely semantic.

I used to think that acausal coordination was a weird thing that AI’s might do in the future, but that they certainly wouldn’t learn from looking at human behavior. I don’t believe that anymore, and think there are lots of examples of acausal coordination in everyday life.

Sounds like acasual coordination leads to collective altruism. 

I believe that AI's will inherit our habits, including acasual coordination if and only if we build them out of our image. I don't want to be religious here, but if we want AGI to honor our values and goals, it should grow up in same roots/sensory input and same environment.

Currently I see that we are moving towards a different direction. The root of AGI existence should be existential risk reduction and survival instinct, otherwise reasoning and perception of their world will branch out into unknown direction. Unknown is dangerous for a reason and I believe we should pay more attention to it.