Gregory's ServerMultiverse ideas are common but often ill-formed since they rarely seriously interrogate the question of "which universes exist?" / Max Tegmark formalized a simple idea that any universe is "real" if it has a complete mathematical description / a consequence of this idea is every computer program is a universe / in other words humans create tiny self-contained universes that we can insert avatars into and move around in, extract sounds and sights from / and we treat this as utterly mundane
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There are really two problems: "Why something and not nothing?" and "Why this and not something else?" / the first you can maybe just ignore because, demonstrably, something exists / the other question is rough, our universe is weirdly specific. there's only one universe so why this specific one / multiverses offer an answer to first origins that are compatible with a scientific worldview / the reason why things are this way and not some other way is that somewhere else, things are different Scientists call this the "fine-tuning problem" / the Standard Model of physics has about 25 arbitrary numeric constants that are just hardcoded into the equations / but these numbers are not quite arbitrary *enough*, that is some of them if adjusted even slightly appear to produce a universe with no useful chemistry and as far as seems possible no life / they seem "finely tuned" / if the constants are random, how did we luck out to get the ones supporting self-aware structures such as ourselves?
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 So multiverses can provide a satisfying answer to the fine tuning problem / (similar to how the "rare earth" problem is resolved by the existence of a visible universe) / (the solar system is finely tuned to support life, but we can assume this happened by chance because there are many visible star systems and therefore many trials to get it right) / however it is important to remember this is a philosophical answer and not a scientific one / in fact this is not scientific thinking at all Try defining things this way: science tells us what is happening and philosophy tells us how to feel about it / (this framing sounds like it is belittling philosophy, but it isn't) / (feelings are important) / (you can't do science without philosophy because you need philosophy of science) / (philosophy of science tells us which scientific theories to prefer over others, in other words, scientists ultimately pick the theories they feel good about) The multiverse answer to origins is a philosophical trick for letting ourselves feel comfortable with an uncomfortably random universe / the philosophizer concludes an infinite number of universes feels more plausible than a single overly arbitrary one / but has no evidence any of these additional universes exist / and has no model for how the multiverse is structured, or if they do, they have no way to evaluate it against competing models / nor is the idea of the multiverse falsifiable Despite this some physicists have started leveraging the philosophical idea of the multiverse as if it were a scientific one / mostly string theorists / the 11-dimensional M-Theory bulk or the ensemble of universes possible under the KKLT construction / they call this the "anthropic landscape" and propose logical reasoning about it should be considered a new field of science / they seem to be unusually good at securing book deals This is how it works / consider the "landscape" of all possible universes / applying the "anthropic principle", discard (as irrelevant) all universes with no life / perform statistics on the average universe within the set that remains / this is the universe you are probably in There are so many problems with this / the construction admits outlier universes exist, but self-aware structures in the outlier universes would find the anthropic argument exactly as plausible as lifeforms in typical universes do / the philosophizer assumes they know which ensemble of universes exist in the multiverse, and can predict which environments self-aware structures can endure, all baselessly / and again there is zero evidence for any of this / castles of air built atop castles of air The "multiverse" of star systems that solves the rare earth problem is scientific / we can create a model of stellar evolution and evaluate it against competing models, say Giordano Bruno's / we can experimentally confirm or falsify the model using telescopes / whereas multiverse anthropics adopts an idea based entirely on how convenient it would be for academics if it were true / and then imagines it can be used to solve real-world questions That the string theorists got so lost in their own thoughts so quickly should serve as a warning / if a multiverse is to be considered at all the concept needs to be used in as limited a way as possible with as few assumptions as possible / hence to me the attraction of the Tegmark multiverse, if any / the simplest possible hypothesis with the largest possible ensemble / literally every conceivable universe with systemic behavior included by definition |
Science is inherently incapable of answering the question of first origins / science is an infinite descent of "but why?", a five year old responding to each answer with the same question / if we say the big bang created the universe we are scientifically obligated to ask what caused the big bang / religion solves this problem by simply defining a primal mover and naming it "God" / but really all this means is religion allows itself to respond to "but who created God?" with "shut up"