# Best effort beliefs

Alice: Hey Bob, how's it going?

Bob: Pretty good. How about you?

Alice: Pretty good. What are you drinking?

Bob: A Bayeslight.

Alice: Cool. Hey bartender, lemme get one of those as well.

Alice: Hey, have you seen President Hanson's new immigration policy?

Bob: No. What is it?

Alice: He's shutting down the borders pretty hard. It's like an 8.5/10 on the left-right political axis, where 10/10 is ultra conservative and 0/10 is ultra liberal.[^lu6hcs73hy]

Bob. Oh gawd. He's such an idiot.

Alice: Oh yeah? What sort of immigration policy would you implement?

Bob: Hm, I think something like a 2/10 on the left-right spectrum.

Alice: And how confident are you in that?

Bob: Probably like an 8/10.

Alice: Ok, let's call this 2/10 on the left-right spectrum belief with an 8/10 confidence a 2-8 belief. I disagree and will bet you $10 on it.

Bob: But how are we going to bet? What are we betting on? What's the resolution criteria?

Alice: *Proposes some clever thing to bet on with crystal clear resolution criteria that perfectly captures everything.*

Bob: Wow. Ok. Yeah, that works. But actually, after thinking about it a little more, I think I'm more like a 2.5-7. Can we bet at those odds instead?

Alice: We can. But only if we can bet $100 instead of $10.

Bob: Oh. Ummmm. Ok, I guess I'm probably more like a 3-6.5. I could do that at $100. Is that ok?

Alice: No. But I'd do 3-6.5 at $1,000. Shake on it?

Bob: Woah... Alice, this got real expensive real fast.

Alice: What's the matter Bob? Do you need to chug a few Bayeslights first?

Bob: Fuck you. I've got a family to feed over here.

Alice: Pansy. Wussy. That's a cop out and you know it.

Bob: *Sigh*. Ok, ok. Let me think about this. I am a Bayesian, and I do agree that Bayesians should be perfectly happy to bet on their beliefs when doing so would be +[EV](https://en.wikipedia.org/wiki/Expected_value).

Alice: Right...

Bob: But... it's just that... well, $1,000 is kind of a lot of money.

Alice: Is it? You're semi-retired. You own your home. Your kids are in college. You have a fund to pay for college. You don't have expensive taste. You always talk about how you'd be perfectly fine retreating to some cabin in the woods somewhere.

Bob: I mean, yeah. You're right.

Alice: Ok, so what's the problem? It looks like things are pretty inelastic. Like, the amount of utility you'd gain if you won $1,000 is pretty much the same as what you'd lose if you lost $1,000. (Save for the initial short-term, Fisher-ian, wussy-pussy feelings of "Oh no, I lost $1,000. What am I going to tell my wife?")

Bob: Ok, ok. I take enough pride in my rationalism that I have to concede that you're right. I should be willing to bet $1,000 on my 3-6.5 belief. But... just... let me think about this for a second.

Alice: Hey bartender, get this guy another Bayeslight!

Bob: Fuck you again, Alice.

Alice: Hold my beer. I'm 'bout to go whup these suckas at some beer pong. Think about your true beliefs while I'm gone Bob. And be ready to bet $1,000 on them.

Bob: Will do. You're an asshole, but thanks for pushing my epistemics in the right direction.

Alice: 😉

Bob: *thinking...*

Alice: Phew! Those guys are a bunch of weirdos over there. They wouldn't bet more than $20. What cowards.

Bob: Ok. So I thought about it, and I determined that my true belief is actually a 4-7. And I'm ready to bet $1,000 on it.

Alice: Cool. How's $10,000 sound?

Bob: WAIT, WHAT??? $10,000?!

Alice: What's the problem?

Bob: I thought you said $1,000?!

Alice: I did say $1,000. Now I'm saying $10,000. Problem?

Bob: WTF Alice!

Alice: Dude, you're being a pansy again. Do we really need to go through this? Why are you so comfortable betting $1,000 and not $10,000? $10,000 is not going to materially impact your life, Bob. We can discuss it, but I'm pretty sure $10,000 is still in "inelastic territory".

Bob: *Sighhhhhhh*

Alice: Do I need to get you another Bayeslight?

Bob: No! No more Bayeslights!

Alice: Do I need to leave you some time to think again?

Bob: No...

Alice: You know you should be perfectly willing to bet $10,000 on your stated belief with the odds I'm offering you, since you're inelastic and it's +EV to you at those odds.

Bob: Well...

Alice: Let me guess: you're not so certain about that 4-7 belief, huh?

Bob: Correct.

Alice: What do you think is going on here?

Bob: I mean, I gotta admit, I started off a little reactionary against President Hanson's immigration policy. I shouldn't have been that confident in my 2-8 belief.

Alice: Yeah. And now?

Bob: Well now I'm just not so sure about my 4-7 belief. For $1,000 I was ready to roll with it. But for $10,000? Well, I'm just thinking about how I underestimated how complicated immigration policy is. I'm thinking about all of these second and third and fourth order effects, and how it's difficult to predict what outcome any given policy will have. Before I was mostly thinking about the first-order effects, and maybe a little bit about the second-order effects, but I'm realizing that this only scratches the surface of the ultimate consequences. I also am realizing that I was focused on how the conservatives just don't understand A, B and C. But now I'm realizing that even if that's true, once you factor in A, B and C, well, there's just so many other things to factor in on top of A, B and C. D, E, F, G, etc. So I guess I'm just feeling pretty uncertain.

Alice: Cool. So what are your true beliefs?

Bob: Um, I don't know. I'd have to really sit down and think about it for a while. Probably spend a few weeks researching things and stuff.

Alice: False. You do in fact have some belief right now, with some level of confidence. Sure, if you spend six weeks researching things you'd probably revise your belief and confidence level, but that doesn't change the fact that you are not a rock and you do in fact, at this very moment, have some belief and have some level of confidence in that belief. C'mon Bob, I thought you were a Bayesian. Do I have to [dutch book](https://en.wikipedia.org/wiki/Dutch_book) you?

Bob: Ugh. No. You don't have to dutch book me. I know that you're right.

Alice: Ok. I won't make you bet $10,000 on it, but what would you say your true beliefs are right now?

Bob: Eh, I think I do, truly, lean slightly towards a liberal immigration policy. But I'm honestly not very confident in it. I think my true belief is something like a 4-2.

Alice: $100?

Bob: *Smiles.* Yes, $100.

*Alice and Bob shake on it.*

Bob: You are still an asshole, but this was actually a good lesson for me.

Alice: I think I'm [more of a dick](https://youtu.be/32iCWzpDpKs), but thanks.

Bob: Haha. And I guess I'm the pussy huh?

Alice: Yup.

* * *

Bob: You're the worst. But hey, let me ask you something. How did you get that job as an oddsmaker for the Economic Policy Prediction Market? My daughter has been talking about pursuing something like that.

Alice: Some lady I met at this bar pushed me until I made a $100,000 bet with her on something related to immigration policy. Then she offered me a job. 

[^lu6hcs73hy]: Please suspend your disbelief. Using numbers like this probably isn't realistic, but it makes the writing easier.