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I’m a big fan of the blog, but disagree with this entry. Her argument could be applied to the idea of the Big Bang itself: we can never receive light from any f

I’m a big fan of the blog, but disagree with this entry. Her argument could be applied to the idea of the Big Bang itself: we can never receive light from any further back than the “surface of last scattering”, so the notion of a hotter prior epoch is an extrapolation. The extrapolation is a good one as it uses independently-tested laws of evolution, at least to the point these laws presumably break down, as she points out. Similarly, it’s entirely conceivable that we may find independent ways to test which of the proposed modifications of the evolution laws is correct, for instance by using data collected from binary mergers. Then, these modified laws would lead to a modified story of what happened near the Big Bang. Alternatively, it may happen that all but one or a few of the proposed modifications do not play nicely with the other forces of nature at a theoretical level. Or maybe not, but we certainly can’t rule out this possibility a priori. Moreover, her point about not having a multi-universe data set would dismiss all of cosmology as mere “ascience” — again, including the notion of the Big Bang itself. Instead, I think it likely that the present multiplicity of early universe proposals will be pruned as more data becomes available.

lambdasquirrel 4y ago
> Her argument could be applied to the idea of the Big Bang itself What's wrong with that? The thing about science is that it cannot pretend that it knows. It needs to prove. To which end, I don't think we should be supposing that we're going to know. Otherwise we're doing religion.
- necovek 4y ago
  Science is, effectively, religion/faith in a particular set of base presumptions (axioms of set theory or logic theory guide all "logical" reasoning). Basically, limits of human mind understanding things come with just having to trust some things are simply so. The biggest difference from things more commonly referred to as "religions" is that science invites you to challenge all these assumptions and look for a better (and smaller, simpler) working set that still explains all the phenomena we observe at least as well as the sets of axioms we currently use. And it knows that all the knowledge we gain is simply the approximation of the real stuff, and that we can only work to improve those approximations.
  - lisper 4y ago
    > Science is, effectively, religion/faith No. No no no no no!!! Science is a process. The result of that process is explanations for phenomena. And the reason this matters is that the particular explanations produced by the scientific process turn out to give you the power to make extraordinarily accurate predictions about (certain aspects of) the future, and thus give you a tremendous amount of leverage in becoming the master of your own fate. It is absolutely not a religion, except insofar as it is the only thing mankind has ever come up with that truly gives us the gift of prophecy.
    - eyelidlessness 4y ago
      Not to lend any credence to the antiscience above, but nothing about science being a process or even the falsifiability and other safeguards of that process preclude it from religious adherence. Even if they’re extraordinarily accurate processes, “it” absolutely can be and sometimes is treated as religious. Elevating science as a process of knowledge acquisition does it a disservice too. Scientists make mistakes, have attachments to their areas of study, and have a lot of complicated incentives that nominally would be anathema to the “process” even if they’re following the process … faithfully.
      - edgyquant 4y ago
        How is it anti science to say the science is just our best approximation?
    - necovek 4y ago
      You may see the above as a critique of science: I actually consider it a positive aspect that puts it way above traditional religions. The fact that I recognize there are both faith and religious elements to science only makes it easier to explain how and why science is better than religion. Note that science similarly includes a lot of areas where our predictions are not "extraordinarily accurate" (all the statistics-based science, like medicine, social sciences...) in any particular case, yet it's still science because we recognize the limits (eg. "with a large number of samples, this will mostly happen").
tsimionescu 4y ago
> Similarly, it’s entirely conceivable that we may find independent ways to test which of the proposed modifications of the evolution laws is correct, for instance by using data collected from binary mergers. Then, these modified laws would lead to a modified story of what happened near the Big Bang. Sure, but you have to start from observations of the binary merger, not from what you'd like the Big Bang to be like, like most of these theories do. Starting from predictions about the origin of the universe is unlikely to produce good testable theories, since there is nothing to test there. You have to look at phenomena that are actually still happening in the universe to guide your research, and only then extrapolate.
- SiempreViernes 4y ago
  Einstein's equations are time reservable and deterministic, so the evolution has only one path and ultimately it doesn't matter which end you start at, you'll get to the other unique end point regardless. The problem is to get the correct start conditions that makes the other end of the path end up somewhere plausible. It is largely a matter of training and temperament if you think it's more rewarding to start from the observations of current phenomena that all have some uncertainty and laboriously work backwards to predict an early universe that doesn't match the observations and then have to start over, or if you think it's better to start from the distant past and work toward the now only to find a problem and having to start over.
  - tsimionescu 4y ago
    Sure, the equations themselves lead to the same place. But this is only true if they are the right equations. If you look at an existing phenomenon that maybe relativity doesn't describe well enough, and find some modification to these equations that explains it better; and then you go and check that indeed this new model explains all known observations better - you have a pretty solid new theory. You can then expand this theory into the early universe and see what consequences it would have for the inflation model. However, if you start from the big bang and want to modify Einstein's equations, what will guide you to a better model? Most likely you will use your intuition on how the universe must have begun - but then, chances are, your modified laws will predict entirely the wrong thing about the current universe; or, you can add terms to the existing equations that have no influence in the current universe, but then, by Occam's razor, your theory should just be discarded since it explains all observable phenomena equally well, but is more complex.
nswest23 4y ago
She does apply it to the big bang as well. She says that it's just the simplest explanation we have and that it's probably wrong too.
- superposeur 4y ago
  As I read the post, she takes the fact of a Hot Big Bang (narrowly construed in the modern sense of a homogenous, hot initial state prior to which vanilla GR breaks down, not as a literal singularity) to be a fact knowable by the normal process of science. Whereas the question of what came before that — I.e. what modified description takes over at higher temperatures yet — is placed in a different epistemic category of forever unknowability. Of course, for any theory that applies within a certain domain, there’s always the question of what happens beyond that domain (“what came before that… and before that… and before that…?”). But this infinite regress isn’t particularly noteworthy. If I understand her correctly, she is claiming to be able to draw a particular line and to say that we can know things on one side of this line but— even in principle — can never know anything past this particular line. She certainly understands her stuff. But I respectfully disagree with her conclusions — I see no reason to think that we might not make progress on the question through the normal process of science.

lambdasquirrel 4y ago

> Her argument could be applied to the idea of the Big Bang itself What's wrong with that? The thing about science is that it cannot pretend that it knows. It needs to prove. To which end, I don't think we should be supposing that we're going to know. Otherwise we're doing religion.

necovek 4y ago
Science is, effectively, religion/faith in a particular set of base presumptions (axioms of set theory or logic theory guide all "logical" reasoning). Basically, limits of human mind understanding things come with just having to trust some things are simply so. The biggest difference from things more commonly referred to as "religions" is that science invites you to challenge all these assumptions and look for a better (and smaller, simpler) working set that still explains all the phenomena we observe at least as well as the sets of axioms we currently use. And it knows that all the knowledge we gain is simply the approximation of the real stuff, and that we can only work to improve those approximations.
- lisper 4y ago
  > Science is, effectively, religion/faith No. No no no no no!!! Science is a process. The result of that process is explanations for phenomena. And the reason this matters is that the particular explanations produced by the scientific process turn out to give you the power to make extraordinarily accurate predictions about (certain aspects of) the future, and thus give you a tremendous amount of leverage in becoming the master of your own fate. It is absolutely not a religion, except insofar as it is the only thing mankind has ever come up with that truly gives us the gift of prophecy.
  - eyelidlessness 4y ago
    Not to lend any credence to the antiscience above, but nothing about science being a process or even the falsifiability and other safeguards of that process preclude it from religious adherence. Even if they’re extraordinarily accurate processes, “it” absolutely can be and sometimes is treated as religious. Elevating science as a process of knowledge acquisition does it a disservice too. Scientists make mistakes, have attachments to their areas of study, and have a lot of complicated incentives that nominally would be anathema to the “process” even if they’re following the process … faithfully.
    - edgyquant 4y ago
      How is it anti science to say the science is just our best approximation?
  - necovek 4y ago
    You may see the above as a critique of science: I actually consider it a positive aspect that puts it way above traditional religions. The fact that I recognize there are both faith and religious elements to science only makes it easier to explain how and why science is better than religion. Note that science similarly includes a lot of areas where our predictions are not "extraordinarily accurate" (all the statistics-based science, like medicine, social sciences...) in any particular case, yet it's still science because we recognize the limits (eg. "with a large number of samples, this will mostly happen").

tsimionescu 4y ago

> Similarly, it’s entirely conceivable that we may find independent ways to test which of the proposed modifications of the evolution laws is correct, for instance by using data collected from binary mergers. Then, these modified laws would lead to a modified story of what happened near the Big Bang. Sure, but you have to start from observations of the binary merger, not from what you'd like the Big Bang to be like, like most of these theories do. Starting from predictions about the origin of the universe is unlikely to produce good testable theories, since there is nothing to test there. You have to look at phenomena that are actually still happening in the universe to guide your research, and only then extrapolate.

SiempreViernes 4y ago
Einstein's equations are time reservable and deterministic, so the evolution has only one path and ultimately it doesn't matter which end you start at, you'll get to the other unique end point regardless. The problem is to get the correct start conditions that makes the other end of the path end up somewhere plausible. It is largely a matter of training and temperament if you think it's more rewarding to start from the observations of current phenomena that all have some uncertainty and laboriously work backwards to predict an early universe that doesn't match the observations and then have to start over, or if you think it's better to start from the distant past and work toward the now only to find a problem and having to start over.
- tsimionescu 4y ago
  Sure, the equations themselves lead to the same place. But this is only true if they are the right equations. If you look at an existing phenomenon that maybe relativity doesn't describe well enough, and find some modification to these equations that explains it better; and then you go and check that indeed this new model explains all known observations better - you have a pretty solid new theory. You can then expand this theory into the early universe and see what consequences it would have for the inflation model. However, if you start from the big bang and want to modify Einstein's equations, what will guide you to a better model? Most likely you will use your intuition on how the universe must have begun - but then, chances are, your modified laws will predict entirely the wrong thing about the current universe; or, you can add terms to the existing equations that have no influence in the current universe, but then, by Occam's razor, your theory should just be discarded since it explains all observable phenomena equally well, but is more complex.

nswest23 4y ago

She does apply it to the big bang as well. She says that it's just the simplest explanation we have and that it's probably wrong too.

superposeur 4y ago
As I read the post, she takes the fact of a Hot Big Bang (narrowly construed in the modern sense of a homogenous, hot initial state prior to which vanilla GR breaks down, not as a literal singularity) to be a fact knowable by the normal process of science. Whereas the question of what came before that — I.e. what modified description takes over at higher temperatures yet — is placed in a different epistemic category of forever unknowability. Of course, for any theory that applies within a certain domain, there’s always the question of what happens beyond that domain (“what came before that… and before that… and before that…?”). But this infinite regress isn’t particularly noteworthy. If I understand her correctly, she is claiming to be able to draw a particular line and to say that we can know things on one side of this line but— even in principle — can never know anything past this particular line. She certainly understands her stuff. But I respectfully disagree with her conclusions — I see no reason to think that we might not make progress on the question through the normal process of science.