4 ms·

Could the anthropic principle taken into conjunction with our continued existence be used to show that the MWI is more probable? Here's the situation that I'm

by calebh 8y ago

Could the anthropic principle taken into conjunction with our continued existence be used to show that the MWI is more probable? Here's the situation that I'm thinking about: it's well known that we've come close to nuclear annihilation multiple times, either by accident or by tensions between the US and the USSR in the Cold War. If the MWI is correct, it is probable that a good chunk of these worlds have been reduced to ash. However, we currently find ourselves in a world where that has not happened, presumably due to the anthropic principle. Could we then give a numerical probability that MWI is correct, based on this fact? I'm not a philosopher or physicist - just an interested layman.

x220 8y ago
No, because you can come up for very good arguments a priori for why two or more rational nuclear powers leads to a very stable world, because every party is very interested in preventing nuclear war if they are materialists.
- perl4ever 8y ago
  Are they good arguments though? Some would say that we observe through declassified information after the fact, that the "rational nuclear powers" were not themselves in control, and a series of accidents at lower levels could have, but didn't, cause disaster, mainly through luck. Similarly, there was a recent thread that had information about how the only reason the first moon landing succeeded was because of a series of accidents, where a computer bug compensated for another unintended defect in the lander. History could have been vastly different via small pivotal events.
philwelch 8y ago
I don't think that's how the anthropic principle works, but I'm not actually sure how the anthropic principle works. To my understanding, the anthropic principle is basically: among the near-infinite set of possible physical laws, we can immediately rule out the ones that would prevent us from being around trying to figure out which physical laws govern the universe. I think there's two varieties of this. The "weak anthropic principle" says, that doesn't mean those laws couldn't exist, there's no weird metaphysics around it, it's just that if the underlying physical laws didn't allow us to exist, you'd just have a universe that didn't have anyone in it and so the physics of that universe would be a moot point that didn't matter to anyone. The "strong anthropic principle" says, wait, no, there is some metaphysical significance to this, and it's somehow not even logically possible for a non-anthropic universe to exist. I find that a little self-absorbed on the part of humanity as a whole, but that would tie in a little better to your quantum suicide idea. The weak anthropic principle, in contrast, would just kind of say, "yeah, there's a chance we all blow ourselves up, and if we do, I guess nobody will be around to care about physics anymore". Even the strong anthropic principle doesn't prove much here. "Nuclear annihilation" probably wouldn't actually result in complete human extinction. Some people would survive. Individual quantum immortality doesn't stop you from shooting a hole through your brain and being neurologically disabled for the rest of your life, so collective quantum immortality also wouldn't stop you from living in a post-apocalyptic hellhole. Also, even the strong anthropic principle doesn't actually mean that humanity can't go extinct; after all, it didn't prevent the universe from existing for billions of years before humans started to exist. Maybe the real strong anthropic principle doesn't even apply to us, it applies to a species of avian hive-minded critters on a planet circling an unnamed star in the Andromeda galaxy, and as a weird side effect of living in a universe that is metaphysically required to permit for the existence of the Andromeda flying hivemind, humanity kind of shows up for a few hundred millennia and gets to do some physics before getting wiped out by a swarm of paperclip maximizers.
- calebh 8y ago
  If the MWI is true, then there must be some universes that would experience multiple highly improbable events. These events would be a hint to residents of that universe that the MWI is correct. Why wouldn't the usual Bayesian analysis apply here?
  - philwelch 8y ago
    Your personal probability of observing a universe that experiences multiple highly improbable events is the same whether or not MWI is true.
  - n4r9 8y ago
    Imagine yourself as a resident of that "universe" (I prefer to think of it as "branch"). Why should a sequence of unlikely events be a distinguisher between different interpretations of a theory, which make the same probabilistic predictions as each other?
tbabb 8y ago
Why, then, don't we find ourselves in universes where the atom bomb was never invented?

by calebh 8y ago

x220 8y ago

No, because you can come up for very good arguments a priori for why two or more rational nuclear powers leads to a very stable world, because every party is very interested in preventing nuclear war if they are materialists.

perl4ever 8y ago
Are they good arguments though? Some would say that we observe through declassified information after the fact, that the "rational nuclear powers" were not themselves in control, and a series of accidents at lower levels could have, but didn't, cause disaster, mainly through luck. Similarly, there was a recent thread that had information about how the only reason the first moon landing succeeded was because of a series of accidents, where a computer bug compensated for another unintended defect in the lander. History could have been vastly different via small pivotal events.

philwelch 8y ago

I don't think that's how the anthropic principle works, but I'm not actually sure how the anthropic principle works. To my understanding, the anthropic principle is basically: among the near-infinite set of possible physical laws, we can immediately rule out the ones that would prevent us from being around trying to figure out which physical laws govern the universe. I think there's two varieties of this. The "weak anthropic principle" says, that doesn't mean those laws couldn't exist, there's no weird metaphysics around it, it's just that if the underlying physical laws didn't allow us to exist, you'd just have a universe that didn't have anyone in it and so the physics of that universe would be a moot point that didn't matter to anyone. The "strong anthropic principle" says, wait, no, there is some metaphysical significance to this, and it's somehow not even logically possible for a non-anthropic universe to exist. I find that a little self-absorbed on the part of humanity as a whole, but that would tie in a little better to your quantum suicide idea. The weak anthropic principle, in contrast, would just kind of say, "yeah, there's a chance we all blow ourselves up, and if we do, I guess nobody will be around to care about physics anymore". Even the strong anthropic principle doesn't prove much here. "Nuclear annihilation" probably wouldn't actually result in complete human extinction. Some people would survive. Individual quantum immortality doesn't stop you from shooting a hole through your brain and being neurologically disabled for the rest of your life, so collective quantum immortality also wouldn't stop you from living in a post-apocalyptic hellhole. Also, even the strong anthropic principle doesn't actually mean that humanity can't go extinct; after all, it didn't prevent the universe from existing for billions of years before humans started to exist. Maybe the real strong anthropic principle doesn't even apply to us, it applies to a species of avian hive-minded critters on a planet circling an unnamed star in the Andromeda galaxy, and as a weird side effect of living in a universe that is metaphysically required to permit for the existence of the Andromeda flying hivemind, humanity kind of shows up for a few hundred millennia and gets to do some physics before getting wiped out by a swarm of paperclip maximizers.

calebh 8y ago
If the MWI is true, then there must be some universes that would experience multiple highly improbable events. These events would be a hint to residents of that universe that the MWI is correct. Why wouldn't the usual Bayesian analysis apply here?
- philwelch 8y ago
  Your personal probability of observing a universe that experiences multiple highly improbable events is the same whether or not MWI is true.
- n4r9 8y ago
  Imagine yourself as a resident of that "universe" (I prefer to think of it as "branch"). Why should a sequence of unlikely events be a distinguisher between different interpretations of a theory, which make the same probabilistic predictions as each other?

tbabb 8y ago

Why, then, don't we find ourselves in universes where the atom bomb was never invented?