6 ms·

You're just stating an anthropic-principle argument here, and unfortunately anthropic arguments tend conceal a fallacy of equivocation. You can look up some of

You're just stating an anthropic-principle argument here, and unfortunately anthropic arguments tend conceal a fallacy of equivocation. You can look up some of William Lane Craig's work for a formal logical analysis showing exactly where it goes wrong, but the traditional plain-language analogy is: Imagine you're sitting in a prison cell, and you've been told you're going to be executed by a firing squad of a dozen expert marksmen, who will shoot you from a distance of only a few feet away. You're led out of your cell, tied to a stake, the marksmen line up, they raise their rifles and aim at you, and you hear the mass bang of their simultaneous firing. And... you discover you are unharmed. All twelve expert marksmen completely missed you, at close range! The anthropic argument says you should be completely unsurprised; after all, the only way for you to be observing the marksmen now is if they all missed, so the probability of them having missed, given that you are observing them, is 1. We should not be surprised by something which has probability 1. While this is trivially true, it is also utterly unconvincing and utterly pointless. You are perfectly justified in being surprised that all the marksmen missed, and here is the equivocation: the anthropic argument tells you not to be surprised, but the thing it tells you not to be surprised at is not the thing that was actually surprising. Your prior for all the marksmen missing and leaving you completely unharmed should have been very, very low, and no amount of ex-post-facto wrangling can change that. Or, put more simply, anthropic arguments can be used to launder any past event to a probability of 1; after all, the probability of event X having happened, given that you observed event X, is always trivially 1. But it tells you nothing useful whatsoever.

acqq 8y ago
> the probability of them having missed, given that you are observing them, is 1. We should not be surprised by something which has probability 1. While this is trivially true, it is also utterly unconvincing and utterly pointless. It's completely convincing to me. If you are unharmed, no single bullet hit you. Even if you've had the "prior" information like that they are "a firing squad of a dozen expert marksmen" if you are "utterly surprised" by the result it probably means that your priors simply miss something, not that it couldn't have happened at all. E.g. maybe that dozen of experts had some additional decision you didn't know about, e.g. they want to influence a regime change and agreed before that it would start with you not being harmed. Such kind of information turns very improbable event to very probable. More than that, even improbable events do happen all the time. It is very improbable that I personally will never win a huge prize on the lottery ticket, but the lotteries are intentionally made that somebody from time to time wins it. If we are a "lottery winner" and don't know anything about the rules of the lottery and the number of the participants, we just can't conclude anything else about the lottery probabilities than that we got what we got. As long as more different universes are possible, no matter how we think our is improbable, as long as we have information only about our state we don't have to be able to conclude more than that we have what we have. So there's no value is empty talk, we know more only by moving the boundaries of what we can measure. We have actually have learned amazingly much about the Universe, but there's no "guaranteed first prize win" ("learning everything") in these endeavors.
- deleted 8y ago
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- ubernostrum 8y ago
  Such kind of information turns very improbable event to very probable. The issue is, as I pointed out, that it works for anything and produces the same result. Anthropic arguments literally consist of stating that "P(A|A) = 1". Which of course is true, but what does that actually tell you?
  - acqq 8y ago
    > The issue is, as I pointed out, that it works for anything If you find it used "for anything" you can point to such cases where it is improperly used. When it is used for the case where we genuinely don't have enough information to claim any "probability" then it is simply a more colorful statement of that fact: that there is really nothing actually measured and known based on which any other statement than "we know exactly one example that such outcome is possible because we live in this outcome" is honestly impossible. You may psychologically not like that fact, but when there is no more data, it has to be admitted that there is no more data to claim anything else than that. Maybe the following can help you: Imagine you find yourself in the middle of the desert, in all directions you see only sand. People today know that every desert ends somewhere, but that's based on the fact that enough people don't live in the middle of the desert, so you must imagine that you are the very first person that ever existed and that you find yourself in the middle of the desert. While moving around the place, looking for any signs, you may or may not find the proofs about something else in the distance. But you can genuinely be in the phase where you see only sand and can't conclude anything about the existence of, for example, the rivers or the sees. The way I see it, the message is not "give up any attempt to learn more about the Universe you are in" the message should be "sitting around and inventing stories doesn't help: you have to move and actively search to find out more." The humanity was for a while good in inventing stories that sounded comforting but were completely unsupported, but we have actually in the last 100 years found the exact and provable signs about much more of our Universe than ever in our history: think about it: 100 years ago nobody knew that there exists anything more than one galaxy: ours. Today we can actually claim that there are one hundred billion galaxies in our Universe. And that most of them move away from ours. And we can calculate very precisely when all of them were on "one place": around 13.8 billion years ago. I'm always so glad that I live in this point of history to be even able to learn about that.(1) If you want more answers, support the science which looks for the answers -- there have to be serious investments in the real experiments for finding out more because easily reachable information is already found. And the humanity sadly invests more in military equipment than in science. And a lot of what we've learned we have learned from the projects that are less "sexy": you don't have to have many humans walking on the moon to learn more about the moon, for example: using robotic probes is all that we need today. But you should also not realistically expect the answers that are behind the limits of what's reachable for us. In the example of the first human in the desert, he can reach some land behind the desert, but being just a first human, walking there, he surely won't walk on the moon. He can however look at the moon and the changes in the shades from the sun on different places on the Earth and develop the idea that the Earth is also round. And that's how scientific discovery works: carefully doing enough experiments to be able to conclude something that was before unknown. 1) to reestablish the perspective for the day-to-day events, search for "Everything Is Amazing And Nobody Is Happy"
red75prime 8y ago
Thanks for in depth explanation why this idea isn't interesting. > But it tells you nothing useful whatsoever. Exactly. Existence of our civilization is not an evidence for the high probability of life emergence, nor for the low probability of that. And the lack of observations of extraterrestrial civilizations is evidence for low probability of life emergence.
thanatropism 8y ago
In probability theory there's the concept of a filtration. Rigorously speaking, probabilities are not attributed to singular events, but to sets (possibly, in the discrete case, single-element sets such as {heads}, {tails}). To be even more precise: a sigma-algebra is a concept of set-of-all-sets that avoids continuous-case paradoxes through technical stuff you can ignore. A filtration is a decreasing sequence of sigma algebras: for example, if your event space is the six numbers a die might show, you could have F(0) = { {}, {die number is odd}, {die number is even}} and F(1) = { {}, {die number is 1},...{die number is 6}, {die number is 1 or 2},...} (a sigma algebra is closed under intersections) What this means is that earlier probabilities are defined on coarser spaces of sets of events as compared to later probabilities. This is how you get dynamic stochastic processes that don't look into the future.

acqq 8y ago

> the probability of them having missed, given that you are observing them, is 1. We should not be surprised by something which has probability 1. While this is trivially true, it is also utterly unconvincing and utterly pointless. It's completely convincing to me. If you are unharmed, no single bullet hit you. Even if you've had the "prior" information like that they are "a firing squad of a dozen expert marksmen" if you are "utterly surprised" by the result it probably means that your priors simply miss something, not that it couldn't have happened at all. E.g. maybe that dozen of experts had some additional decision you didn't know about, e.g. they want to influence a regime change and agreed before that it would start with you not being harmed. Such kind of information turns very improbable event to very probable. More than that, even improbable events do happen all the time. It is very improbable that I personally will never win a huge prize on the lottery ticket, but the lotteries are intentionally made that somebody from time to time wins it. If we are a "lottery winner" and don't know anything about the rules of the lottery and the number of the participants, we just can't conclude anything else about the lottery probabilities than that we got what we got. As long as more different universes are possible, no matter how we think our is improbable, as long as we have information only about our state we don't have to be able to conclude more than that we have what we have. So there's no value is empty talk, we know more only by moving the boundaries of what we can measure. We have actually have learned amazingly much about the Universe, but there's no "guaranteed first prize win" ("learning everything") in these endeavors.

deleted 8y ago
[deleted]
ubernostrum 8y ago
Such kind of information turns very improbable event to very probable. The issue is, as I pointed out, that it works for anything and produces the same result. Anthropic arguments literally consist of stating that "P(A|A) = 1". Which of course is true, but what does that actually tell you?
- acqq 8y ago
  > The issue is, as I pointed out, that it works for anything If you find it used "for anything" you can point to such cases where it is improperly used. When it is used for the case where we genuinely don't have enough information to claim any "probability" then it is simply a more colorful statement of that fact: that there is really nothing actually measured and known based on which any other statement than "we know exactly one example that such outcome is possible because we live in this outcome" is honestly impossible. You may psychologically not like that fact, but when there is no more data, it has to be admitted that there is no more data to claim anything else than that. Maybe the following can help you: Imagine you find yourself in the middle of the desert, in all directions you see only sand. People today know that every desert ends somewhere, but that's based on the fact that enough people don't live in the middle of the desert, so you must imagine that you are the very first person that ever existed and that you find yourself in the middle of the desert. While moving around the place, looking for any signs, you may or may not find the proofs about something else in the distance. But you can genuinely be in the phase where you see only sand and can't conclude anything about the existence of, for example, the rivers or the sees. The way I see it, the message is not "give up any attempt to learn more about the Universe you are in" the message should be "sitting around and inventing stories doesn't help: you have to move and actively search to find out more." The humanity was for a while good in inventing stories that sounded comforting but were completely unsupported, but we have actually in the last 100 years found the exact and provable signs about much more of our Universe than ever in our history: think about it: 100 years ago nobody knew that there exists anything more than one galaxy: ours. Today we can actually claim that there are one hundred billion galaxies in our Universe. And that most of them move away from ours. And we can calculate very precisely when all of them were on "one place": around 13.8 billion years ago. I'm always so glad that I live in this point of history to be even able to learn about that.(1) If you want more answers, support the science which looks for the answers -- there have to be serious investments in the real experiments for finding out more because easily reachable information is already found. And the humanity sadly invests more in military equipment than in science. And a lot of what we've learned we have learned from the projects that are less "sexy": you don't have to have many humans walking on the moon to learn more about the moon, for example: using robotic probes is all that we need today. But you should also not realistically expect the answers that are behind the limits of what's reachable for us. In the example of the first human in the desert, he can reach some land behind the desert, but being just a first human, walking there, he surely won't walk on the moon. He can however look at the moon and the changes in the shades from the sun on different places on the Earth and develop the idea that the Earth is also round. And that's how scientific discovery works: carefully doing enough experiments to be able to conclude something that was before unknown. 1) to reestablish the perspective for the day-to-day events, search for "Everything Is Amazing And Nobody Is Happy"

red75prime 8y ago

Thanks for in depth explanation why this idea isn't interesting. > But it tells you nothing useful whatsoever. Exactly. Existence of our civilization is not an evidence for the high probability of life emergence, nor for the low probability of that. And the lack of observations of extraterrestrial civilizations is evidence for low probability of life emergence.

thanatropism 8y ago

In probability theory there's the concept of a filtration. Rigorously speaking, probabilities are not attributed to singular events, but to sets (possibly, in the discrete case, single-element sets such as {heads}, {tails}). To be even more precise: a sigma-algebra is a concept of set-of-all-sets that avoids continuous-case paradoxes through technical stuff you can ignore. A filtration is a decreasing sequence of sigma algebras: for example, if your event space is the six numbers a die might show, you could have F(0) = { {}, {die number is odd}, {die number is even}} and F(1) = { {}, {die number is 1},...{die number is 6}, {die number is 1 or 2},...} (a sigma algebra is closed under intersections) What this means is that earlier probabilities are defined on coarser spaces of sets of events as compared to later probabilities. This is how you get dynamic stochastic processes that don't look into the future.