All of dadadarren's Comments + Replies

The more I think about anthropics the more I realize there is no rational theory for anthropic binding. For the question "what is the probability that I am the heavy brain?" there really isn't a rational answer. 

2mako yass6mo
I agree that there doesn't seem to be a theory, and there are many things about the problem that makes reaching any level of certainty about it impossible (the we can only have one sample thing). I do not agree that there's a principled argument for giving up looking for a coherent theory. I suspect it's going to turn out to be like it was with priors about the way the world is: Lacking information, we have just fall back on solomonoff induction. It works well enough, and it's all we have, and it's better than nothing. So... oh... we can define priors about our location in the in terms of the complexity of a description of their locations. This feels like most of the solution, but I can't tell, there are gaps left, and I can't tell how difficult it will be to complete the bridges.

This experimental outcome will not produce a disagreement between Alice and Bob. As long as they are following the same anthropic logic. 

When saying Bob's chance of survival is 100% according to MWI,  the statement is made from a god's eye view discussing all post-experiment worlds: Bob will for sure survive: in one/some of the branches. 

By the same logic, from the same god's eye view, we can say, Alice will meet Bob for sure: in one/some of the branches, if the MWI is correct. 

By saying Alice shall see Bob with a 0.1% chance no matter ... (read more)

Try this for practice, reasoning purely objectively and physically, can you recreate the anthropic paradoxes such as the Sleeping Beauty Problem?

That means without resorting to any particular first-person perspective, nor using words such as "I" "now" "here", or putting them in a unique logical position. 

One way to understand the anthropic debate is to consider them as different ways of interpreting the indexicals (such as "I" "now" "today" "our generation" etc) in probability calculation. And they are based on the first-person perspective. Furthermore, there is the looming question of "what should be considered observers?". Which lacks any logical indicator, unless we bring in the concept of consciousness. 

We can easily make the sleeping beauty problem more undefined. For example, by asking "Is the day Monday?". Before attempting to answer it one wou... (read more)

The two are incompatible. Anthropic reasoning makes explicit use of first-person experience in their question formulation. E.g. in the sleeping beauty problem, "what is the probability that now is the first awakening?" or "today is Monday?" The meaning of "now", and "today" is considered to be apparent, it is based on their immediacy to the subjective experience. Just like which person "I" am is inherently obvious based on a first-person experience. Denying first-person experience would make anthropic problems undefined.

Another example is the doomsday argu... (read more)

3the gears to ascension8mo
they're perfectly compatible, they don't even say anything about each other [edit: invalidated]. anthropics is just a question of what systems are likely. illusionism is a claim about whether systems have an ethereal self that they expose themselves to by acting; I am viciously agnostic about anything epiphenomenal like that, I would instead assert that all epiphenomenal confusions seem to me to be the confusion "why does [universe-aka-self] exist", and then there's a separate additional question of the surprise any highly efficient chemical processing system has at having information entering it, a rare thing made rarer still by the level of specifity and coherence we meat-piloting skin-encased neural systems called humans seem to find occurring in our brains. there's no need to assert that we are separately existenceful and selfful from the walls, or the chair, or the energy burn in the screen displaying - they are also physical objects. their physical shapes don't encode as much fact about the world around them though; our senses are, at present, much better integrators of knowledge. and it is the knowledge that defines our agency as systems that encodes our moral worth. none of this requires seperate privileged existence different from the environment around us; it is our access consciousness that makes us special, not our hard consciousness.
The two are unrelated. Illusionism is specifically about consciousness (or rather its absence), while anthropics is about particular types of conditional probabilities and does not require any reference to consciousness or its absence. Denying first person experience does not make anthropic problems any more undefined than they already are.

Whether computer-simulated minds or people from other universes (or beyond the event horizon in this post) have subjective experiences is essentially the reference class problem, a category of observers that "I could be" in anthropic arguments: Whether the reference class should include them.

I have a major problem with this "observation selection" type of anthropic reasoning, which pretty much is all that ever gets discussed such as SSA, SIA and their variants. In my opinion, there isn't any valid reference class. Each person's perspective, e.g. who I am, ... (read more)

For what it's worth I think there needs to be some clarification. 

I didn't say our model is deterministic nor should it be or not. And my argument is not about whether the correct definition of knowledge should be "justified true belief". And unless I have had the wrong impression, I don't think Sean Carrol's focus is on the definition of knowledge either. Instead, it's about what should be considered "true".

The usual idea of a theory being true if it faithfully describes an underlying objective physical reality (deterministic or not)  is problem... (read more)

Not intentional, but didn't expect it to be a novel argument either. I suspect everyone has thought about it sometime during their life, likely while learning physics in secondary school. I just think "cognitive instability" is a nice handle for the discussion.

I really like "starting with being an agent". In fact, I strongly argued for it. But the reality is people often would forgo this and regard "view from nowhere" as the foundation and attempt to draw the map with that perspective. (Anthropics being the prime example, IMO) Allowing this switch of viewpoints, there is no way to say if "the internal model for decision-making" really "reflects the universe". E.g. the debate if quantum states are just epistemological or ontological. 

Even the idea of "decision" is challenged when the decision-maker is physic... (read more)

That's quite alright, none taken. All I was getting at was a uniquely "physically real" analysis is actually an additional assumption. 

Do you think there is a causal reason why you are MSRayne? Meaning why you are experiencing the world from that particular physical person's perspective? Instead of you being Bill Gates, or an astroid, or a quark? 

I am unable to rationally engage in this conversation, see my response to ChristianKI [] above. I'm sorry if I insulted you.

"There can be only one true explanation for any given event" is actually what I am challenging. PBR supposes reasoning and physical descriptions have to be based on a prespecified perspective. And there is no one "true explanation" that transcends all perspectives. 

By PBR's logic, the perspective center being not physically describable is to be expected. That's what I meant by "why quantum physics does not cover the observer" because physics actually shouldn't. I am not claiming I know more than physicists. If you are interested in quantum interpretat... (read more)

PBR suggests physics reasoning has to be conducted from something's perspective, instead of a "god's eye view" or "view from nowhere". 

Call this thing at the perspective center "self". From this perspective, the world around can be physically described/analyzed based on the interactions with the self. This means to physically analyze something we have to reason from the perspective of something else that interacts with it. It cannot be done from its own perspective. This is the reason why "observers" are not covered by quantum physic btw. 

The sel... (read more)

This is self-contradictory. There can be only one true explanation for any given event. But you are positing two separate co-occurring explanations: one (mysterious, undefined "free will" which somehow relates to what you "choose" to do) from the inside point of view, and one (brain states and their transformation over time) from the outside point of view. Either these are the same thing, meaning "free will" isn't free and is just the way a certain computation feels from the inside, or there are too many causes. And claiming that this is why "observers aren't covered by quantum physics" puts you near crackpot "I understand QM better than actual physicists!!" woo territory. Steelmanning your argument, the best interpretation I can come up with is "Conscious minds have free-willed choices in the sense that it is impossible to put a probability distribution on their actions (due to the I stuff), and whenever two conscious minds interact, their separate subjective timelines coalesce into a shared timeline mediated by matter arranged in a way that perfectly mirrors their subjective experience. Mind comes first, matter is the external representation of mind used in shared universes for communication between minds, and the apparent history of the particles making up a mind is a result of its sequence of (totally inexplicable, like the splitting experiment) choices resulting in its being the specific entity that it is, which causes it to manifest in the apparently-physical shared universe in the specific way it does." Is this close to your actual view?

You can say even when neither of them can compare the descriptions it still means their descriptions are the same. But from what perspective is this statement made? It is from a god's eye view that directly thinks in terms of reality.  

A self-consistent theory only means from any perspective, analyzing the interactions affected by an object cannot give conflicting descriptions of said object. If the only interaction upon you from the camera is an infra-red photo of the bottle, and from your direct interaction with the bottle you concluded it's red, an... (read more)

Okay, I disagree :-)

Perspectives here do not just mean spatiotemporal locations. More importantly, it means which thing you are. e.g. you are experiencing the universe from the perspective of a particular human being named mikbp. 

Treating perspectives to be axiomatic means any physical description has to be based on the perspective of something. We cannot think from a god's eye view, and directly describe the world as it is. As in think directly in terms of the "absolute reality". 

If there are no interactions between two observers, then how can either of them say th... (read more)

  They cannot. But why is it relevant? The fact that they don't know it does not mean that their description is not the same. In addition, different observers may get different descriptions (eg. an infrared camera does not record the same as a normal camera). That does not change the object observed, just what we know about it. As long as you don't think you know everything about the objects you observe, this is fine. The more we know, the more physical laws we can infer. Taking the God's eye view is restricted to specific problems and it just implies that you know all you need to know for that problem. Of course that's not something one can do all the time.

"Absolute objectivity" is treating physical objects as the foundation. I.e. Observers 1 and 2 should give the same depiction of the bottle, on pain of being wrong, because they are describing the same physical object.  It attempts to get rid of perspectives and reason directly in terms of this physical objective reality by taking a "view from nowhere". It fits our usual intuition of scientific objectivity: "think about how things really are instead of how they appear to be from various viewpoints". 

If we treat perspectives to be axiomatic then th... (read more)

I still don't get it, sorry. No2. doesn't seem needed to me. You can observe at different times so observers do not interact. You may not see exactly the same, yes. Probably my objection comes from that I think that "there is simply no way to say [whether the object is the same]" does not imply that absolute reality does not exist. But it is highly probable that I just don't understand something in your reasoning (eg. I don't know what "treat perspectives to be axiomatic" means).

Questions like this highlight how misguided the current state of anthropic reasoning is. 

When one spends enough time thinking about the anthropic principle it would seem quite reasonable to raise this question. But take a step back, and consider it a physical/scientific statement: "The universe is likely in the simplest form that could support intelligent life". It is oddly specific. Why not say "the universe is likely the simplest that could support black holes?", or hydrogen atoms, or Very large-scale integrations? Each hypothesis results in vastly ... (read more)

I see it as less of "Humans are more reliable than AI" but more of "Humans and AI do not tend to make the same kind of mistakes". And the everyday jobs we encounter have been designed/evolved around human mistake patterns so we are less likely to cause catastrophic failures. Keeping the job constant and replacing humans with AI would obviously lead to problems. 

For well-defined simple jobs like arithmetic, AI has a definite accuracy edge compared to human beings. Even for complex jobs, I am still unsure if human beings have the reliability edge. We ha... (read more)

2Chanchana Sornsoontorn1y
Yeah. I think they have different kinds of errors. We are using human judgement to say that AIs should not make errors that humans would not make. But we do not appreciate the times when they do not make errors that we would make. Humans might be more reliable at driving cars than AIs overall. But human reliability is not a superset of AI. It's more like an intersection. If you look at car crashes made by AIs, they might not look like something that human would cause. But if you look at car crashes of humans, they might also not look like something that AIs would cause.

Interested in this too. The idea of taxing on the value of the land, not on the improvements seems impractical. Even if we do not consider the buildings/infrastructures on a particular parcel, the land's value is heavily influnced by its location. e.g. its accessibility to nearby services and improvements. So the tax would either still be influenced by improvements or we tax downtown at the same rate as a removed desolate farm. Then the tax rate would be too low. 

This is doable via a number of different methods; see this overview of such methods [].
1Yair Halberstadt1y
The tax is intended to reflect improvements to nearby land insofar as they make this piece of land more valuable. That is fine, since it doesn't discourage improving this piece of land, and at the same time acts to force those who don't have a good use of the land to sell it.

Most interesting. Though with a very different motivation, (I was trying to resolve the anthropic paradoxes) I have also concluded that self-locating uncertainties or indexical uncertainties do not have meaningful probabilities.

Yes, and the observer-centered perspective is accompanied by the rejection of the notion of "absolute reality". Like relativity to absolute spacetime. In my opinion, the interpretive challenges of QM are nothing different. "Observer" is simply anything's perspective one wishes to conduct the physical analysis from. 

My original motivation for this topic was trying to solve anthropic paradoxes, which are surprisingly closely connected to quantum interpretations and the metaphysics of science and consciousness. 

The questions surrounding conscious experiences and splits, e.g. which color "I" will likely see afterward, etc, intrinsically use the concept of a first-person perspective. I.e. they take which Ebborian is "I" as something inherently apparent. But physics doesn't answer "why you are you and I am me?", or why "I am experiencing the world from the perspective of this particular object?". It will be a big surprise if the Ultimate Grand Unified Theory of Everything could answer this. Put it another way, if it does answer that, then Po'mi's questions would hav... (read more)

Yes! any characteristic works as long as it is preselected. But it needs to be actually selected or sampled. 

Yet there is no sampling in anthropic problems. SIA assumes the first-person "I" (or "now") is equivalent to a random sample. So it treats finding myself as the person who's been created in room 73 the same way as if an external observer selected room 73 and finds someone exists in it. It is just an assumption that lacks any logical backing.

The same can be said about SSA too. 

SIA is equivalent to making a Bayesian update as if god  (a non-reference class external observer) asks the question "Does the person with these characteristics (the characteristics of the physical person "I") exist?" and gets a positive answer. (AKA. Update on one's existence)

But why would god focus on those specific characteristics and raise that question at all. It makes sense for someone to be biased towards themself, such as you focusing on the name avturchin, and me on the name dadadarren, but why would a non-reference class external observer pa... (read more)

In some sense, situation with SIA looks like as p-hacking: we select a hypothesis after we got the data. But if we preselect uniqueness, any type of uniqueness works. For example, cells are numbered. Before the experiment, we choose the number 73. In that case, discovering that 73 was hit will be strong update for 100 attempts vs. only 10 attempts. 

Sometimes I wonder what would Kant think of the interpretive challenges of quantum mechanics. I get the feeling that people consider quantum puzzling precisely because we regard physical objects as noumenal reality rather than phenomenal conceptions. So that we like to think about the world from a Copernicus type of "birds-eye view" rather than from "our perspectives", more aligned with Kant's view. 

Can I suggest my solution to anthropics? Selfishness is discussed here. 

Smart people keep trying to find ways to explain how is my experience selected from all observer experiences. SSA favours Doomsday Argument? add potential observers to the refernce class; SIA fairs poorly for theories with large/infinite number of observers? try to find a claw method to counter that....

We should seriously consider maybe there is no logical explanation to questions  like "which observer I am?", or "which observer's experience is mine?". 

Good read. Reminds me about "Extraordinary claims require extraordinary evidence."

They are definitely polar opposites. But disagreeing with one does not automatically means endorsing another. 

Open individualism: there is no reason to say dadadarren is the self while Britney Spears is not. Me: no reasoning is needed. I know the subjective experience of dadadarren not Britney. So I am dadadarren not Britney. That's it. 

You saying there are two selves makes me wonder if we are having similar thoughts. IMO, the current dadadarren and yesterday's dadadarren are definitely two different persepectives. So one MAY say I am an empty in... (read more)

Actually, we could define three levels of Self and they will correspond to different types of individualism. 1. "Atman" level - universal light of attention, which is present in any observer. It corresponds to open individualism if I care only about pure attention. 2. Qualia level - the combination of qualia which I experience now. Empty individualism. 3. Long-term memory level or "historical Self" - closed individualism. Some think that the atman level is real and it is a universal observer which looks through all really existing observers. In that case, we could calculate chances that the universal observer will observe some peculiar observer-moment. But in physicalism "atman" is not real.  The ideas of "death" and "personal identity" are applicable only on the third level.  Most philosophers tend to say that only one of these three levels are real and-or valuable and thus they have to chose between the types of individualism. For me all three are valuable. If I am interested in self-location believes, I mostly think about them using the third level,

Yes, I do think there is no direct way to define who is the "future self". Since there is no experience of the future. Self-identity only works up to the current moment. There is no direct way to identify the future me or the future first-person. Heck, I can't even be sure there would be someone who considers the current me as their past self the next morning. For all I know, this physical person could die of a heart attack tonight. 

It is Ok to say all agents who consider the current me as their past first-person are the "future self". From any of tho... (read more)

I see "empty individualism" as an opposite to open individualism. In this view, I exist only now, just one moment, so there is no any continous identity. But only I-now have qualia. There are no past or future qualia.  I don't fully endorse this view.  In my view, there are two Selves, historical and momentary, which are constantly interwined.  

The black box example shows the arbitrariness in the regular anthropic school of thought (SSA and SIA etc). It is a counterargument against them. So in this sense, it does work in my favour. However, I feel obligated to point out that my argument here (PBR) is quite different. 

I am arguing that even if the exact process of copying is completely known there is still no reasonable way to assign a self-locating probability. Because the "self" or "I" in question is primitively identified and perspective dependent, which cannot be defined from a "god's eye... (read more)

The main problem I see is with probabilities of my future observer-moments. You said: "...should be based on first-person experience. The current me can say I have the past first-person experience (memory) of being dadadarren" That is ok for current and past observer-moments, but if we apply it to the future observer-moments, we will have a problem: Either I can say: "Any future observer-moment which will have memory of being avturchin, will be me, and now I can calculate their distribution and probabilities". But here I am using God's view perspective. Or I can observe that any future observer-moment is not me-now.  Therefore, there is no way to assign probabilities to "me being that moment". There is no future and planning is impossible.  Here, being in the first-hand perspective, I am ending with something like "empty individualism", the idea that I exist only now. So we either return to the outside view perspective, or conclude that we can't predict anything. The problem may be not trivial, as Hume first mentioned, when he wrote about the impossibility of induction. For example, in the forking everettian multiverse, future probabilities are different from the past ones.

The link point back to this post. But I also remember reading similar arguments from halfer before, that the answer changes depending on if it is true quantum randomness, could not remember the source though.

But the problem remains the same: can Halfers keep the probability of a coin yet to be tossed at 1/2, and remain Bayesian. Michael Titelbaum showed it cannot be true as long as the probability of "Today is Tuesday" is valid and non-zero. If Lewisian Halfer argues that, unlike true quantum randomness, a coin yet to be tossed can have a probability diffe... (read more)

If I am understanding correctly, you are saying if the sleeping beauty problem does not use a coin toss, but measures the spin of an election instead, then the answer would be different. For the coin's case, you will give the probability of Heads (yet to be tossed ) as 2/3 after learning it is Monday. But for the spin's case, or a quantum coin, the probability must be 1/2 after learning it is Monday as it is a quantum event yet to happen.

That seems very ad-hoc to me. And I think differentiating "true quantum randomness" with something "99.99999% inevitable... (read more)

1Viktor Rehnberg1y
I haven't followed your arguments all the way here but I saw the comment and would just jump in and say that others have made a similar arguments. The one written example I've seen is this Master's Thesis [ Widstam.pdf].  I'm not sure if I'm convinced but at least I buy that depending on how the particular selection goes about there can be instances were difference between probabilities as subjective credences or densities of Everett branches can have decision theoretic implications. Edit: I've fixed the link

I have been thinking about anthropics for quite some time. And in the process also noticed its connection with embedded agency and its connection with freewill like the Newcomb problem

My conclusion is perspectives are axiomatic. e.g. You inherently know that "I am this person (Antoine de Scorraille)", just like I know "I am this person (dadadarren)". It is purely based on the fact that the only subjective experience available is due to this physical body. "Which person/thing is the self?" has no underlying logical reason or physical explanation. It ... (read more)

There are quite a few points here I disagree with. Allow me to explain. 

As I said in the previous reply, a mathematical statement by itself doesn't have a probability of being right/wrong. It is the process under which someone makes or evaluates said statement that can have a probability attached to it. Maybe the experimenter picked a random number from 1 to 10000 and then check that digit of pi to determine whether to destroy or wake the copy in question. And he picked ten in this case. This process/circumstance enables us to assign a probability to ... (read more)

There’s a general consensus that, although quantum theory has changed our understanding of reality, Newtonian physics remains a reliable short term guide to the macro world. In principle, the vast majority of macro events that are just about to happen are thought to be 99.9999% inevitable, as opposed to 100% like Newton thought.  From that I deduce that if a coin is shortly to be flipped, the outcome is unknown but, is as good as determined as makes no odds. Whereas if a coin is flipped farther into the future from a point of prediction, the outcome is proportionately more likely to be undetermined.  I’m willing to concede debate about this. What I do recognise is that Beauty’s answer of 2/3 Heads, after she learns it’s Monday, depends on it being an already certain but unknown outcome. Whereas if the equivalent of a quantum coin were to be flipped on Monday night, this makes a difference. In that case, awaking on Monday morning, Beauty would not yet be in a Heads world or a Tails world. Her answer would certainly be 1/2 , after she learns it’s Monday. What it would be before she learns it’s Monday would depend on what quantum theory model is used. I can consider this another time. Perspective disagreement between interacting parties, as a result of someone having more than one possible self-locating identity, is something I can certainly see a reason for. Invalidating someone’s likelihood of what that identity might be, I can't find a reason for. I’ve looked hard.  I’d like to explore your simplified experiment. First it’s important to distinguish precisely what happens with Heads to the version of me that is not woken during the experiment. If the other me is woken after the experiment and told this fact, then there’s no controversy. On finding myself awake in the experiment, my answer is definitely 1/3 for Heads and 2/3 for Tails. Furthermore, it should makes no difference which version might have woken inside the experiment and which outside, assuming the coi

Well in that case yes. 3rd person's perspective is just a shorthand for the perspective of a god's eye view. We should not switch perspectives halfway in any given analysis. 

I'm not sure what 1 position and 3 position mean here. I would summarize my argument as the first-person perspective is based on subjective experience. It is a primitive notion that cannot be logically analyzed. Just like in Euclidean geometry we can't analyze any of its axioms. Take then as given, that's it. 

All the rest, like no self-locating probability, perspective disagreement, rejection of doomsday argument and presumptuous philosopher, double-halving in sleeping beauty, and rejection of fine-tuned universe, are just conclusions based on that. 

1 position = first-person perspective, 3 position = third-person perspective

For a, my opinion is while objectively there is no probability for the value of a specific digit of Pi, we can rightly say there is an attached probability in a specific context.

For example, it is reasonable to ask why I am focusing on the tenth digit of Pi specifically? Maybe I just happen to memorize up to the ninth digit, and I am thinking about the immediate next one. Or maybe I just arbitartily choose the number 10. Anyway, there is a process leading to the focus of that particular digit. If that process does not contain any information about what tha... (read more)

Well in that case, it narrows down what we agree about. Mathematical propositions aren’t events that happen. However, someone who doesn’t know a specific digit of Pi would assign likelihood to it’s value with the same rules of probability as they would to an event they don’t know about. I define credence merely as someone’s rational estimate of what’s likely to be true, based on knowledge or ignorance. Credence has no reason to discriminate between the three types of reality I talked about, much less get invalidated. I would also highlight that almost all external outcomes in the macro world, whether known or unknown, are already determined, as opposed to being truly random. In that sense, an unknown coin flip outcome is just as certain as an unknown mathematical proposition. In the case of Sleeping Beauty being told it’s Monday and that a coin will be flipped tonight, she is arguably already in a Heads world or a Tails world. It’s just that no-one knows which way the coin will land. If so, Lewis’s version of halfing is not as outlandish as it appeared. Beauty’s 2/3 update on Monday that the coin will land Heads is not actually an update on a future random event. It is an update on a reality that already exists but is unknown. From Beauty’s perspective, if she's in a Heads world, she is certain it is Monday. If the world is Tails, she doesn’t have that certainty. Therefore an increased likelihood in Heads, once she learns it’s Monday, is reasonable – assuming that self-locations allow credences. I submit that, since she was previously not certain that the day she found herself awake on was Monday, a non-zero credence that this day was Tuesday legitmately existed before being eliminated.  Below is a version of Sleeping Beauty that mixes the three types of reality I described – contingent, analytic and self-location. On Sunday night, Beauty is put to sleep and cloned. A coin is flipped. If it lands Heads, the original is woken on Monday and questioned, while the cl

I think the very idea of "I am a typical observer" is misguided. Because "observer" is a target drawn around where the arrow is. The arrow is the first person "I" in this analogy.

Everyone knows who the first-person "I" refers to since the only subjective experience felt is due to that particular physical body. We then put physical systems similar to this body into a category, and give it a name. But what similar feature is chosen to perform this grouping is arbitrary. From my personal perspective, such groups can be middle-aged men, things that can do simp... (read more)

I think that what you said here and elsewhere could boil down to two different views: 1. Going from 1 position to 3 position in probabilities sense is ontologically impossible, period. No meaningful probability updates. 2. We need to take hard look on what is "I", "observer", and "typical", and only after we clearly define them, we could said something meaningful about probabilities.  I tend here to agree with the second view, and I explored different aspects of it in some of my posts. 

I find the word "meta" has been frequently used in a different connotation. Very often it does not mean "an X about X", but simply "look at X (itself) from a higher-level, outsider perspective". 

The first word that jumps into my mind is "Meta-ethics". It is less of "the ethics of ethics" but more of "what does ethics itself mean?", akin to the later use of the word "meta". 

Personally, I would love it if these meanings are expressed by different words. But language is a tricky thing that involves too many things besides strict definitions. 

Agree! That's part of what I meant by "The fact that it now has other meanings in narrow contexts...". I would guess that "meta-ethics" specifically is in analogy to metaphysics, though I couldn't verify that with a quick google.

I would regard the world in 1900 as a "complex civilization capable of thinking about DA". It's just that nobody bothered to think about it or publish their thoughts. So shouldn't we expect our society to remain that capability for another 120 years? At the same time, we also expect everyone to stop thinking about DA in 50 years. Because DA has been only discussed for 50 years so far?

For any choice of reference of class to have the same prediction of the future, that prediction would effectively be a mirror image of the past. 

BTW, what is your opinion about medocrity principle, that is, the idea of typicality of you, me and Earth? 
To get more credible estimates with 90 per cent confidence, it better to take just order of magnitude. In that case, the apparent strange overconfidence of DA predictions dissappears as well as its mirror structure. So we can say that both ability to think about DA and the thinking about it will exist for several decades. (Note also that Laplace seems to be the first who was close to DA, and it was in 1801)

This actually demonstrates the problem further. If using "civilization" as the reference class then as you said humans would stop thinking about DA in about 50 years since it started 50 years ago. But what if we use "people thinking about DA" as the reference class? Due to the internet giving it more exposure, there are a lot more people thinking about DA now than in the 80s and 90s. If I am in the middle of all these people, then we would likely stop thinking about DA a lot sooner.

Similarly, human civilization has existed for about 5000 years so it would ... (read more)

I agree with your prediction: complex civilization capable to think about DA will collapse soon, in a few decades, but some form of medieval civilization can exist a few millennia. It is completely normal and typical outcome, if we ignore hopes on space exploration. This staged collapse prediction is what follows from the idea that “each reference class has its own end”: for the reference class of DA thinkers the end is nigh. For written civilization it is in few thousands years.

I think he is describing the paradox of supernatural predicting power suggested by the doomsday argument and SSA in general. It will boost the probability of scenarios with a smaller reference class. Like in the sleeping beauty problem, SSA suggests the probability of heads is 2/3 after learning now is Monday, even though the toss is yet to happen.

Following similar logic, the astronaut can boost his survival chance by limiting the number of people saved. He can form this intention: select and reheat the passengers one by one. As soon as he feels he has bee... (read more)

This maybe sounds more like he is preventing possible futures in which he doesn't exist, like if I rig a world destroying bomb when I die then a larger percentage of possible futures will have an older me. 

Not sure what you mean. Doomsday argument is about how to think about the information that the first-person "I" is a particular physical person. It suggests treating it the same way as if a random sampling process has selected said physical person. SIA agrees with using sampling process, but disagrees with the range it is sampled from.

This is a hard concept to grasp. But if my understanding is correct, I think you have described a legitimate paradox, especially for physicalism. If everything is physical and nothing beyond, and physics can be explained by math (in terms of values of fundamental constants and various laws), then how come only one particular set of values are physical ("real"), while others are not. There seems to be a missing deciding factor not explained by math or physics. 

An obvious way out is of course to say "all mathematical possible universes ARE real. Physics... (read more)

That is the position of some DA supporters. Not all. I would even hesitate to call it mainstream. 

Anyway, let's say that is the dominating take on DA. Is avturchin committing genocide of future generations by discussing it on an open forum, making more people aware of the doomsday argument? 

Don’t think real risk here, as almost all who read this post, knew about DA. Are there anybody who never heard about it and become interested? But Carter was afraid to publish about DA for 10 years, probably for similar reasons.
3Quintin Pope1y
I think that most futures where we succeed at realizing our cosmic potential, we become competent enough that we stop thinking about doomsday arguments (or at least leave such thoughts to superhuman AIs). But yes, I do think we should discuss DA less often.

The problem with the Doomsday Argument is not it's too pessimistic about the future. One can be as optimistic or pessimistic about humanity's future as he likes. But according to DA that prior belief must inevitably get much bleaker once he considers his own birth rank. 

One's own birth rank is information about which physical person the first person is: "out of all the human beings which one is me". It is perspective-specific, yet it is used to make conclusions on something perspective-independent: the total number of human beings ever exists. If DA's... (read more)


The "I" is primitively defined by the first-person perspective. After waking up from the experiment, you can naturally tell this person is "I".It doesn't matter if there exists another copy physically similar to you. You are not experiencing the world from their perspective. 

You can repeat the experiment many times and count your first-person experience. That is the frequentist model. 

Grabby Alien works on similar logic to well-known anthropic camps such as SSA and SIA: consider what we are as an Observation Selection Effect. As you wrote, treat ourselves as random selections from a list containing everyone. The main difference is regular anthropic camps typically apply this to individual observers, while grabby alien applies it to civilizations. 

Whether this reflects good anthropic reasoning is hard to answer. If one endorses regular anthropic camps then Grabby Alien's logic is at least incomplete. It should incorporate how many o... (read more)

But my explanation for perspective disagreement is based on the primitive nature of the first-person perspective. i.e. it cannot be explained therefore incommunicable. If we say there is A GOOD WAY to understand and explain it, and we must use assign self-locating probabilities this way, then why don't we explain our perspectives to each other as such, so we can have the exact same information and eliminate the disagreement? 

If we say the question has different sample spaces for different people, which is shown by repeating the experiment from their r... (read more)

Hi Dadarren. I haven’t forgotten our discussion and wanted to offer further food for thought. It might be helpful to explore definitions. As I see it, there are three kinds of reality about which someone can have knowledge or ignorance.    Contingent – an event in the world that is true or false based on whether it did or did not happen. Analytic – a mathematical statement or expression that is true or false a priori. Self-location – an identity or experience in space-time that is true or false at a given moment for an observer.  I’d like to ask two questions that may be relevant. a) When it comes to mathematical propositions, are credences valid? For example, if I ask whether the tenth digit of Pi is either between 1-5 or 6-0, and you don’t know, is it valid for you to use a principal of indifference and assign a personal credence of 1/2?   b) Suppose you’re told that a clone of you will be created when you’re asleep. A coin will be flipped. If it lands Head, the clone will be destroyed and the original version of you will be woken. If it lands Tails, the original will be destroyed and the clone will be woken. Finding yourself awake in this scenario, is it valid to assign a 1/2 probability that you’re either the original or clone? I would say that both these are valid and normal Bayesian conditioning applies. The answer to b) reflects both identity and a contingent event, the coin flip. For a), it would be easy to construct a probability puzzle with updatable credences about outcomes determined by mathematical propositions.  However I’m curious what your view is, before I dive further in.
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