"The error" could mean: the false thing that is being asserted; the reason why it is false; or the cognitive mistake which allows it to escape detection.

Maybe I should begin with the true thing that is being asserted! Which is that the number of ink blots can depend on definition, or on the judgment or whim of the individual observer. That is indeed true.

It also may or may not be true that the number of branches, worlds, blobs, etc., in a wavefunction is similarly undefined, or dependent on a somewhat arbitrary definition.

What I deem to be categorically false is the proposition that this is also true of "observers", or "portions of reality that can contain observers" (which might be called worlds or branches), or even just "portions of reality like the one that I find myself in" (which is a definition not involving observers, except incidentally).

The reason that this is false, is that the arbitrariness of the number of blobs, arises from the arbitrariness of their definition. Their very existence is in some sense arbitrary, relative, observer-dependent. It is because their existence is relative, that their number is relative.

The existence of the observed portion of reality is not "relative"; it is definitely there, and it is not caused by the contingent and changeable decisions of some observer about how to divide up reality. On the contrary, the observer here is part of the branch or world; their role is simply to register the fact that it exists, not to have created it.

Why isn't this reasoning used to criticize and rule out theories in which the existence of worlds and branches is vague and definition-dependent? This is what the post is actually about. At some level, it must be nothing more than a failure to combine fact A (this interpretation says worlds in the wavefunction are vague) with fact B (the existence of the real world can't be vague) in order to draw the obvious conclusion (this interpretation must be wrong). But how does this work psychologically? I was hoping some believers in the "Oxford school" would describe how they arrived at their belief, but it seems I first have to communicate why this belief is so problematic.

Acting without apparent fear of the consequences, even stupidly, is often respected as long as you get away with it.

But you didn't get away with it.

Also, technically, you acted like a creep, not a jerk. (A jerk acts boldly, a creep is sneaky and opportunistic.)

Other people (that I have talked to) seem to be divided on whether it was a good thing to do or not.

It sure was one hell of a low status signal. The worst possible way you can fail a shit test is to get visibly hurt and angry.

As for whether she deserved it, well, if you want to work in the kitchen, better be prepared to stand the heat. Expecting women you hit on to follow the same norms of behavior as your regular buddies and colleagues, and then getting angry when they don't, is like getting into a boxing match and then complaining you've been assaulted.

You assaulted her because she asked for an expensive drink, you gave her the drink, and then she ignored you?

You say you don't recommend what you did, but I'm curious about why, considering that you seem to think she deserved it.

There are also some reliable proxies of fitness that are no longer reliable, for example height (can be modified by higher shoes - a trick that women have cottoned on to, but men are totally missing out on).

Not entirely, although there does seem to be some shame attached to doing this.

I do much the same thing by wearing hiking boots everywhere. They're waterproof, well-insulated for cold weather, and also increase my height more than sneakers.

After a short time, they ask you to buy them a drink.

I have never encountered or heard of this behaviour. I would be rather startled if someone I had just met asked me to buy them a drink. I'd guess they were too poor to get their own (and with all respect to poor people, my interest in pursuing a relationship with them would substantially diminish).

I can understand your explanation, but I would find an opposite explanation just as plausible (they are trying to determine if the cost of a drink is a mere trifle to you, hence buying them one = good).

Is this a culturally specific thing? Where is this action, with this meaning, a standard pattern of behaviour?

If that were the case, the camera might show the person being killed; indeed, that is 50% likely.

Yep. But Stuart_Armstrong's description is asking us to condition on the camera showing 'you' surviving.

Pre-selection is not the same as our case of post-selection. My calculation shows the difference it makes.

It looks to me like we agree that pre-selecting someone who happens to survive gives a different result (99%) to post-selecting someone from the pool of survivors (50%) - we just disagree on which case SA had in mind. Really, I guess it doesn't matter much if we agree on what the probabilities are for the pre-selection v. the post-selection case.

Now, if the fraction of observers of each type that are killed is the same, the difference between the two selections cancels out. That is what tends to happen in the many-shot case, and we can then replace probabilities with relative frequencies.

I am unsure how to interpret this...

One-shot probability is not relative frequency.

...but I'm fairly sure I disagree with this. If we do Bernoulli trials with success probability p (like coin flips, which are equivalent to Bernoulli trials with p = 0.5), I believe the strong law of large numbers implies that the relative frequency converges almost surely to p as the number of Bernoulli trials becomes arbitrarily large. As p represents the 'one-shot probability,' this justifies interpreting the relative frequency in the infinite limit as the 'one-shot probability.'

Is that a "yes" or a "no" for the scenario as I posed it?

The way you set up the decision is not a fair test of belief.

I agree. It is only possible to fairly "test" beliefs when a related objective probability is agreed upon, which for us is clearly a problem. So my question remains unanswered, to see if we disagree behaviorally:

the stakes are more like $1.50 to $99.

That's not my intention. To clarify, assume that:

• the other prisoners' decisions are totally independent of yours (perhaps they are irrational), so that you can in no sense effect 99 real other people to guess blue and achieve a $99 payoff with only one beating, and

• the payoffs/beatings are really to the prisoners, not someone else,

Then, as I said, in that scenario I would guess that I'm in a blue room.

Would you really guess "red", or do we agree?

(My "reasons" for blue would be to note that I started out overwhelmingly (99%) likely to be in a blue room, and that my surviving the subsequent coin toss is evidence that it did not land tails and kill blue-roomed prisoners, or equivalently, that counterfactual-typically, people guessing red would result in a great deal of torture. But please forget why; I just want to know what you would do.)

I have been attacking it by deriving the right answer from general considerations (that is, P(tails) = 1/2 for the 1-shot case

Let me instead ask a simple question: would you actually bet like you're in a red room?

Suppose you were told the killing had happened (as in the right column of Cupholder's diagram, and required to guess the color of your room, with the following payoffs:

• Guess red correctly -> you earn $1.50

• Guess blue correctly -> you earn $1.00

• Guess incorrectly -> you are terribly beaten.

Would you guess red? Knowing that under independent repeated or parallel instances of this scenario (although merely hypothetical if you are concerned with the "number of shots"),

• "guess heads" mentality typically leads to large numbers of people (99%) being terribly beaten

• "guess blue" mentality leads to large numbers of people (99%) earning $1 and not being beaten

• this not an interactive scenario like the Prisoner's dilemma, which is interactive in a way that renders a sharp distinction between group rationality and individual rationality,

would you still guess "red"? Not me. I would take my survival as evidence that blue rooms were not killed, and guess blue.

If you would guess "blue" for "other reasons", then we would exhibit the same behavior, and I have nothing more to discuss. At least in this case, our semantically different ways of managing possibilities are resulting in the same decision, which is what I consider important. You may disagree about this importance, but I apologize that I'm not up for another comment thread of this length.

If you would really guess "red", then I have little more to say than to reconsider your actions, and to again excuse me from this lengthy discussion.

I'll try to clarify what I'm thinking of as the relevant kind of selection in this exercise. It is true that the condition effectively picks out - that is, selects - the probability branches in which 'you' don't die, but I don't see that kind of selection as relevant here, because (by my calculations, if not your own) it has no impact on the probability of being behind a blue door.

What sets your probability of being behind a blue door is the problem specifying that 'you' are the experimental subject concerned: that gives me the mental image of a film camera, representing my mind's eye, following 'you' from start to finish - 'you' are the specific person who has been selected. I don't visualize a camera following a survivor randomly selected post-killing. That is what leads me to think of the relevant selection as happening pre-killing (hence 'pre-selection').