4 ms·

I'm more inclined to go with the anthropic principle, where we're observing this universe with these particular physical constants because the other universes (

by ansible 10y ago

I'm more inclined to go with the anthropic principle, where we're observing this universe with these particular physical constants because the other universes (with slightly different constants) are a largely undifferentiated soup of basic particles.

cauterized 10y ago
Why can't it be both?
- ansible 10y ago
  Aside from the high temperature of the early universe, we haven't seen evidence that the physical laws are changing over time, much less 'adapting' in some way. What's the pressure for them to change? What's the reward for them to stay stable now?
  - ivoras 10y ago
    On the other hand, we haven't directly observed the universe for a long enough time (billions of years) to say it's not changing, so we simply don't know. We don't even know if the universe is homogeneous. For example, all we know about distant stars is complete conjecture and approximation based on testing various ideas to see which one fits. We simply don't know if "gravity" is exactly the same for all of them. Small variations of G would still light them up.
    - ansible 10y ago
      We've been looking back in time billions of years, because we look at objects billions of light-years away. If there's anything amiss about how gravity or whatever isn't working like it used to, that's news to me. I haven't heard of even a hint or something like that.
  - cauterized 10y ago
    I was more asking why the two hypotheses have to be mutually exclusive.
unit91 10y ago
This doesn't really address the core issue, though. The anthropic principle may tell us why we're capable of observing the universe, but it doesn't tell us why there is something to observe (instead of nothing), and why the laws and fundamental constants are the way they are.
- wodenokoto 10y ago
  Isn't there some basic question in physics that simply can't be answered, similarly to how axioms in math simply can't be proved. > but it doesn't tell us why there is something to > observe (instead of nothing), and why the laws and > fundamental constants are the way they are. I'm no physicist, but I simply cannot imagine candidate answers to such questions.
  - unit91 10y ago
    > Isn't there some basic question in physics that simply can't be answered, similarly to how axioms in math simply can't be proved. See above. My comment was in response to ansible's reply to themgt. themgt was asking why the universe looks the way it does, and ansible responded with the anthropic principle. The problem with ansible's line of thinking is that the anthropic principle tells me a great deal about me (why I can exist and observe), but not much about the universe, which was themgt's question. In response to your broader objection that there are some basic questions in physics that can't be answered, let me point out that the entire project of physics is to seek material causes for the structure of the universe. So if nature is all that exists, and the universe itself only has material causes, what are those causes? The entire field of cosmology dedicated to answering exactly this question, and many believe it's capable of doing so. As far as Leibniz's famous question "why is there something rather than nothing?" is concerned: admittedly this is a metaphysical question, not a physical question. Still, I think we owe it to ourselves to answer this question too, and not simply dismiss it out of hand. > I'm no physicist, but I simply cannot imagine candidate answers to such questions. Even if this is true, it tells us something about you but not about the universe. By analogy, somehow my body "knew" to put my liver in my torso, not in my neck. I cannot begin to imagine what physical processes led to the proper placement of my liver, but we certainly shouldn't take this to mean there are no reasons. Moreover, we shouldn't sell ourselves short in these matters. Undoubtedly, given enough study I could discover what others have said about organ placement during embryonic development and have a fairly robust understanding of the best of our knowledge regarding the topic. The same is true of cosmology and philosophy.

by ansible 10y ago

cauterized 10y ago

Why can't it be both?

ansible 10y ago
Aside from the high temperature of the early universe, we haven't seen evidence that the physical laws are changing over time, much less 'adapting' in some way. What's the pressure for them to change? What's the reward for them to stay stable now?
- ivoras 10y ago
  On the other hand, we haven't directly observed the universe for a long enough time (billions of years) to say it's not changing, so we simply don't know. We don't even know if the universe is homogeneous. For example, all we know about distant stars is complete conjecture and approximation based on testing various ideas to see which one fits. We simply don't know if "gravity" is exactly the same for all of them. Small variations of G would still light them up.
  - ansible 10y ago
    We've been looking back in time billions of years, because we look at objects billions of light-years away. If there's anything amiss about how gravity or whatever isn't working like it used to, that's news to me. I haven't heard of even a hint or something like that.
- cauterized 10y ago
  I was more asking why the two hypotheses have to be mutually exclusive.

unit91 10y ago

This doesn't really address the core issue, though. The anthropic principle may tell us why we're capable of observing the universe, but it doesn't tell us why there is something to observe (instead of nothing), and why the laws and fundamental constants are the way they are.

wodenokoto 10y ago
Isn't there some basic question in physics that simply can't be answered, similarly to how axioms in math simply can't be proved. > but it doesn't tell us why there is something to > observe (instead of nothing), and why the laws and > fundamental constants are the way they are. I'm no physicist, but I simply cannot imagine candidate answers to such questions.
- unit91 10y ago
  > Isn't there some basic question in physics that simply can't be answered, similarly to how axioms in math simply can't be proved. See above. My comment was in response to ansible's reply to themgt. themgt was asking why the universe looks the way it does, and ansible responded with the anthropic principle. The problem with ansible's line of thinking is that the anthropic principle tells me a great deal about me (why I can exist and observe), but not much about the universe, which was themgt's question. In response to your broader objection that there are some basic questions in physics that can't be answered, let me point out that the entire project of physics is to seek material causes for the structure of the universe. So if nature is all that exists, and the universe itself only has material causes, what are those causes? The entire field of cosmology dedicated to answering exactly this question, and many believe it's capable of doing so. As far as Leibniz's famous question "why is there something rather than nothing?" is concerned: admittedly this is a metaphysical question, not a physical question. Still, I think we owe it to ourselves to answer this question too, and not simply dismiss it out of hand. > I'm no physicist, but I simply cannot imagine candidate answers to such questions. Even if this is true, it tells us something about you but not about the universe. By analogy, somehow my body "knew" to put my liver in my torso, not in my neck. I cannot begin to imagine what physical processes led to the proper placement of my liver, but we certainly shouldn't take this to mean there are no reasons. Moreover, we shouldn't sell ourselves short in these matters. Undoubtedly, given enough study I could discover what others have said about organ placement during embryonic development and have a fairly robust understanding of the best of our knowledge regarding the topic. The same is true of cosmology and philosophy.