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This is excellent. Interview going over more here: https://scientiasalon.wordpress.com/2015/02/13/lee-smolin-and-the-status-of-modern-physics/ https://scientias

by themgt 11y ago

This is excellent. Interview going over more here: https://scientiasalon.wordpress.com/2015/02/13/lee-smolin-and-the-status-of-modern-physics/ https://scientiasalon.wordpress.com/2015/02/13/lee-smolin-an... "As Roberto Mangabeira Unger and I argue in our new book The Singular Universe, the most important discovery cosmologists have made is that the universe has a history. We argue this has to be extended to the laws themselves. Biology became science when the question switched from listing the species to the dynamical question of how species evolve. Fundamental physics and cosmology have to transform themselves from a search for timeless laws and symmetries to the investigation of hypotheses about how laws evolve." and "Neurosciences are a fabulous area to work in, ripe for great discoveries. I’ve always felt this and indeed the only alternative to a career in physics that ever attracted me was a brief flirtation in college with neuroscience. But that is a field which is as bedeviled by outdated metaphysical baggage as physics is. In particular, the antiquated idea that any physical system that responds to and processes information is isomorphic to a digital programmable computer is holding back progress."

danbruc 11y ago
When you listen to some contemporary physicists like Nima Arkani-Hamed they seem to disagree, i.e. they believe that neither time nor space are fundamental properties of our universe but instead emerge from something more fundamental. [1] This leads of course to some really hard problems and especially it is no longer clear what physics is even about. It used to be the science of things moving through space over time, but what if you lose space and time? [1] http://www.cornell.edu/video/nima-arkani-hamed-spacetime-is-doomed http://www.cornell.edu/video/nima-arkani-hamed-spacetime-is-...
- DougMerritt 11y ago
  > they believe that neither time nor space are fundamental properties of our universe but instead emerge from something more fundamental. Yes, this has gained increasing acceptance ever since its first (?) suggestion from the late illustrious John Archibald Wheeler in the 1960s, and it is a very compelling idea, although yes, it makes it hard to conceive what we may be talking about. > like Nima Arkani-Hamed they seem to disagree, I missed it, who's disagreeing with whom about what? The parent comment doesn't seem to have content disagreeing, unless I'm missing something.
Retric 11y ago
There is no difference between physical laws and meta-laws. Aka if the rule is light speed = age of universe then that's just the rule not speed of light is X and slowly changing.
- darkmighty 11y ago
  I agree. Indeed, Einstein used a this principle to formulate relativity: the principle states that the laws of physics don't vary across time or space. Indeed, properties of spacetime change from one location to another, so one could be inclined in formulating only "local laws of physics", and stating those laws change from location to location according to mass distribution among other things. But it's much more elegant to simply formulate "global laws of physics" and have constants/parameters vary in space or time.
  - DougMerritt 11y ago
    > the principle states that the laws of physics don't vary across time or space. This is a special case of a Noetherian invariant: all global conservation laws follow from a symmetry. https://en.wikipedia.org/wiki/Noether%27s_theorem https://en.wikipedia.org/wiki/Noether%27s_theorem > Indeed, properties of spacetime change from one location to another, so one could be inclined in formulating only "local laws of physics", and stating those laws change from location to location according to mass distribution among other things. Ummm...you got it right on the first try, whereas this restatement has gone into the weeds. Local conditions (values of variables, you could say) change; the laws do not. The final part seems to go back on track again, but by then I'm confused what you're saying. Perhaps you're just using some kind of counterfactual as a rhetorical method or something.
    - tagrun 11y ago
      >>the principle states that the laws of physics don't vary across time or space. > This is a special case of a Noetherian invariant: all global conservation laws follow from a symmetry. No, it isn't. I'm afraid you don't know what you're talking about. Spatial translation symmetry lead to conservation momentum, time invariance lead to conservation of energy. No symmetry leads to "physical laws are same everywhere". That's just something you have to assume and can't derive.

by themgt 11y ago

danbruc 11y ago

When you listen to some contemporary physicists like Nima Arkani-Hamed they seem to disagree, i.e. they believe that neither time nor space are fundamental properties of our universe but instead emerge from something more fundamental. [1] This leads of course to some really hard problems and especially it is no longer clear what physics is even about. It used to be the science of things moving through space over time, but what if you lose space and time? [1] http://www.cornell.edu/video/nima-arkani-hamed-spacetime-is-doomed http://www.cornell.edu/video/nima-arkani-hamed-spacetime-is-...

DougMerritt 11y ago
> they believe that neither time nor space are fundamental properties of our universe but instead emerge from something more fundamental. Yes, this has gained increasing acceptance ever since its first (?) suggestion from the late illustrious John Archibald Wheeler in the 1960s, and it is a very compelling idea, although yes, it makes it hard to conceive what we may be talking about. > like Nima Arkani-Hamed they seem to disagree, I missed it, who's disagreeing with whom about what? The parent comment doesn't seem to have content disagreeing, unless I'm missing something.

Retric 11y ago

There is no difference between physical laws and meta-laws. Aka if the rule is light speed = age of universe then that's just the rule not speed of light is X and slowly changing.

darkmighty 11y ago
I agree. Indeed, Einstein used a this principle to formulate relativity: the principle states that the laws of physics don't vary across time or space. Indeed, properties of spacetime change from one location to another, so one could be inclined in formulating only "local laws of physics", and stating those laws change from location to location according to mass distribution among other things. But it's much more elegant to simply formulate "global laws of physics" and have constants/parameters vary in space or time.
- DougMerritt 11y ago
  > the principle states that the laws of physics don't vary across time or space. This is a special case of a Noetherian invariant: all global conservation laws follow from a symmetry. https://en.wikipedia.org/wiki/Noether%27s_theorem https://en.wikipedia.org/wiki/Noether%27s_theorem > Indeed, properties of spacetime change from one location to another, so one could be inclined in formulating only "local laws of physics", and stating those laws change from location to location according to mass distribution among other things. Ummm...you got it right on the first try, whereas this restatement has gone into the weeds. Local conditions (values of variables, you could say) change; the laws do not. The final part seems to go back on track again, but by then I'm confused what you're saying. Perhaps you're just using some kind of counterfactual as a rhetorical method or something.
  - tagrun 11y ago
    >>the principle states that the laws of physics don't vary across time or space. > This is a special case of a Noetherian invariant: all global conservation laws follow from a symmetry. No, it isn't. I'm afraid you don't know what you're talking about. Spatial translation symmetry lead to conservation momentum, time invariance lead to conservation of energy. No symmetry leads to "physical laws are same everywhere". That's just something you have to assume and can't derive.