justinpombrio

Karma: 751

justinpombrio 2 May 2026 14:36 UTC
2 points
0
in reply to: Vanilla_cabs’s comment on: Just Use Bayes: Sleeping Beauty and Monty Hall
I agree. I didn’t notice the significance of the “when you are first awakened” clause, and agree that makes the answer ¹⁄₂. I interpreted it as “right after site is woken up, be it in Monday or Tuesday”, though that’s in retrospect not what it’s saying, it’s saying “on Monday”.

You know, Wikipedia shows two versions of the problem, one of which uses that clause and one of which doesn’t, and doesn’t note the difference (that I’ve seen). This problem really is a mess of hard to notice ambiguous wordings, with a little bit of philosophy problem underneath.

justinpombrio 28 Mar 2026 3:59 UTC
11 points
2
on: Just Use Bayes: Sleeping Beauty and Monty Hall

Why do people answer 1⁄3 to Sleeping Beauty?

There’s a simpler explanation. You say yourself that the answer to this original question is 1/2:

When you are first awakened, to what degree ought you believe that the outcome of the coin toss is Heads?

and that the answer to this slightly different question is 1/3:

When you are first awakened, to what degree ought you believe that your guess will be correct if you guess the coin toss was Heads?

People disagree about the answer to the Sleeping Beauty problem because those questions are nearly identical and easy to confuse. And because in almost all circumstances the answer to questions that vary this way is the same, so you don’t need to distinguish them.

Bit of a side note, but personally the distinction I like to draw is between the probability that the coin landed heads or tails (which happens on Sunday, exactly once, and has two possible events, giving the answer ¹⁄₂), and the probability that Beauty observes heads (which happens on Monday or maybe Tuesday, and has three possible events, giving the answer ¹⁄₃).

justinpombrio 5 Mar 2026 20:54 UTC
3 points
0
in reply to: Measure’s comment on: Rational Chess
Or more simply:
1. Player 1 makes a move for White.
2. Player 2 has the option to switch colors.
3. Play continues with Reversed Armageddon, where White wins ties.
I think this would work so long as Player 1 is capable of making a bad enough first move to cancel out White’s huge advantage from both going first and winning draws. (And ideally there would be more than one move that’s about that bad, so that the opening doesn’t always start the same way.)

justinpombrio 8 Dec 2025 15:46 UTC
1 point
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on: Eliezer’s Unteachable Methods of Sanity
“There exists a place in your cognition that feels like an expectation but actually stores an action plan that your body will follow, and you can load plans into it.” is a valuable insight and I’m not sure I’ve seen it stated quite in that form elsewhere.

Do you have more you could say about how cognition works, or reliable references to point at?

Everything I’ve read is either true but too specific or low level to be useful (on the science end) or mixed with nonsense (on the meditation end), and my own mind is too muddled to easily distinguish true facts about how it works from almost-true facts about how it works. This makes building up a reliable model really hard.

justinpombrio 29 Nov 2025 16:33 UTC
7 points
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on: The Missing Genre: Heroic Parenthood—You can have kids and still punch the sun
I believe you’re looking for A Half-Built Garden. Thought provocing hard sci-fi book about motherhood, community, gender, ecology, and aliens. I highly recommend it, in general and especially given your desired genre.

justinpombrio 25 Mar 2025 17:16 UTC
5 points
2
in reply to: Joseph Miller’s comment on: Will Jesus Christ return in an election year?
The market named “This Market Will Resolve No At The End Of 2025” will resolve to No at the end of 2025. Like it says in its title. What’s unclear about this?

justinpombrio 21 Feb 2025 3:59 UTC
3 points
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in reply to: EniScien’s comment on: Arbital has been imported to LessWrong
The fact that you so naturally used the word “version” here (it was essentially invisible, it didn’t feel like a terminology choice at all) suggests that “version” would be a good term to use instead of “lens”. Downside being that it’s a sufficiently common word that it doesn’t sound like a Term of Art.

justinpombrio 20 Jan 2025 16:52 UTC
1 point
−2
in reply to: Said Achmiz’s comment on: Don’t ignore bad vibes you get from people
Let’s apply some data to this!

I’ve been in two high-stakes bad-vibe situations. (In one of them, someone else initially got the bad vibes, but I know enough details to comment on it.) In both cases, asking around would have revealed the issue. However, in both cases the people who knew the problematic person well, had either a good impression of them, or a very bad impression of them. Because there’s a pattern where someone who’s problematic in some way is also charismatic, or good at making up for it in other ways, etc. So my very rough model of these situations is that there were a bunch of people you could have asked about them and gotten “looks fine” with 60% probability or “stay the fuck away” with 40% probability. If you have only have a few data points of this variety, you’d want to trust your vibes because false negatives can be very costly.

stick to public spaces for a first date, do a web search for the person’s name, establish boundaries and stick to them, be prepared with concrete plans to react to signs of danger, etc.

These mitigations would do nothing against a lot of real relationship failures. Imagine that everything goes swimmingly for the first year. Then you start to realize that even though everything your partner has been doing makes sense on the surface, if you step back and look at the big picture their actions tend to have the effect of separating you from your friends and blaming yourself for a lot of things, and it just doesn’t seem healthy. When you finally decide to break up, it’s an extremely painful process because: (i) your partner is better at weaving stories than you, and from their perspective you’re the problematic person (ii) your friends all know your partner, and they’ve made a good impression, (iii) you will continue to see them at social events, and (iv) even after all of this, you don’t think they ever purposefully acted maliciously toward you.

justinpombrio 18 Dec 2024 3:33 UTC
1 point
0
on: Everything you care about is in the map
Or in the words of Sean Carroll’s Poetic Naturalism:
1. There are many ways of talking about the world.
2. All good ways of talking must be consistent with one another and with the world.
3. Our purposes in the moment determine the best way of talking.
A “way of talking” is a map, and “the world” is the territory.

justinpombrio 25 Nov 2024 22:25 UTC
1 point
0
on: Alignment is not intelligent
The orthogonality thesis doesn’t say anything about intelligences that have no goals. It says that an intelligence can have any specific goal. So I’m not sure you’ve actually argued against the orthogonality thesis.

justinpombrio 24 Nov 2024 3:50 UTC
6 points
−3
in reply to: AnthonyC’s comment on: Which things were you surprised to learn are metaphors?
And English has it backwards. You can see the past, but not the future. The thing which just happened is most clear. The future comes at us from behind.

justinpombrio 24 Nov 2024 1:58 UTC
1 point
0
on: A very strange probability paradox
Here’s the reasoning I intuitively want to apply:

$(X \to Y) \to P [Y | Z] \geq P [X | Z]$

where X = “you roll two 6s in a row by roll N”, Y = “you roll at least two 6s by roll N”, and Z = “the first N rolls are all even”.

This is valid, right? And not particularly relevant to the stated problem, due to the “by roll N” qualifiers mucking up the statements in complicated ways?

justinpombrio 21 Nov 2024 22:44 UTC
6 points
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in reply to: SarahNibs’s comment on: Which things were you surprised to learn are not metaphors?
Where’s the pain?

justinpombrio 18 Nov 2024 21:02 UTC
6 points
4
in reply to: Anders Lindström’s comment on: “It’s a 10% chance which I did 10 times, so it should be 100%”
Sure. For simplicity, say you play two rounds of Russian Roulette, each with a 60% chance of death, and you stop playing if you die. What’s the expected value of YouAreDead at the end?
- With probability 0.6, you die on the first round
- With probability 0.4*0.6 = 0.24, you die on the second round
- With probability 0.4*0.4=0.16, you live through both rounds
So the expected value of the boolean YouAreDead random variable is 0.84.

Now say you’re monogamous and go on two dates, each with a 60% chance to go well, and if they both go well then you pick one person and say “sorry” to the other. Then:
- With probability 0.4*0.4=0.16, both dates go badly and you have no partner.
- With probability 20.40.6=0.48, one date goes well and you have one partner.
- With probability 0.6*0.6=0.36, both dates go well and you select one partner.
So the expected value of the HowManyPartnersDoYouHave random variable is 0.84, and the expected value of the HowManyDatesWentWell random variable is 0.48+2*0.36 = 1.2.

Now say you’re polyamorous and go on two dates with the same chance of success. Then:
- With probability 0.4*0.4=0.16, both dates go badly and you have no partners.
- With probability 20.40.6=0.48, one date goes well and you have one partner.
- With probability 0.6*0.6=0.36, both dates go well and you have two partners.
So the expected value of both the HowManyPartnersDoYouHave random variable and the HowManyDatesWentWell random variable is 1.2.

Note that I’ve only ever made statements about expected value, never about utility.

justinpombrio 18 Nov 2024 18:02 UTC
5 points
0
in reply to: Anders Lindström’s comment on: “It’s a 10% chance which I did 10 times, so it should be 100%”

Probability of at least two success: ~26%

My point is that in some situations, “two successes” doesn’t make sense. I picked the dating example because it’s cute, but for something more clear cut imagine you’re playing Russian Roulette with 10 rounds each with a 10% chance of death. There’s no such thing as “two successes”; you stop playing once you’re dead. The “are you dead yet” random variable is a boolean, not an integer.

justinpombrio 18 Nov 2024 15:01 UTC
4 points
4
in reply to: Anders Lindström’s comment on: “It’s a 10% chance which I did 10 times, so it should be 100%”
If you’re monagamous and go to multiple speed dating events and find two potential partners, you end up with one partner. If you’re polyamorous and do the same, you end up with two partners.

One way to think of it is whether you will stop trying after the first success. Though that isn’t always the distinguishing feature. For example, you might start 10 job interviews at the same time, even though you’ll take at most one job.

justinpombrio 18 Nov 2024 6:05 UTC
5 points
4
on: “It’s a 10% chance which I did 10 times, so it should be 100%”
However it is true that doing something with a 10% success rate 10 times will net you an average of 1 success.

For the easier to work out case of doing something with a 50% success rate 2 times:
- 25% chance of 0 successes
- 50% chance of 1 success
- 25% chance of 2 successes
Gives an average of 1 success.

Of course this only matters for the sort of thing where 2 successes is better than 1 success:
- 10% chance of finding a monogamous partner 10 times yields 0.63 monogamous partners in expectation.
- 10% chance of finding a polyamorous partner 10 times yields 1.00 polyamorous partners in expectation.
EDIT: To clarify, a 10% chance of finding a monogamous partner 10 times yields 1.00 successful dates and 0.63 monogamous partners that you end up with, in expectation.

justinpombrio 4 Nov 2024 14:55 UTC
4 points
1
in reply to: João Ribeiro Medeiros’s comment on: The Median Researcher Problem

IQ over median does not correlate with creativity over median

That’s not what that paper says. It says that IQ over 110 or so (quite above median) correlates less strongly (but still positively) with creativity. In Chinese children, age 11-13.

justinpombrio 29 Oct 2024 20:35 UTC
3 points
0
in reply to: justinpombrio’s comment on: The Case For Bullying
And for a visceral description of a kind of bullying that’s plainly bad, read the beginning of Worm: https://parahumans.wordpress.com/2011/06/11/1-1/

justinpombrio 29 Oct 2024 17:00 UTC
3 points
1
on: The Case For Bullying
I double-downvoted this post (my first ever double-downvote) because it crosses a red line by advocating for verbal and physical abuse of a specific group of people.

Alexej: this post gives me the impression that you started with a lot of hate and went looking for justifications for it. But if you have some real desire for truth seeking, here are some counterarguments:
- https://slatestarcodex.com/2014/11/21/the-categories-were-made-for-man-not-man-for-the-categories/
- https://www.astralcodexten.com/p/contra-kirkegaard-on-evolutionary