Slashdot Mirror
Domain: edge.org
Stories and comments across the archive that link to edge.org.
Comments · 307
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Interview with Barbour
This guy's been doing the circuit for his new book.
There is an interview and a discussion of his stuff at
Edge. -
Julian Barbour is NOT a crackpotIHPP (I have a PhD in physics) so I presume I can comment here. A lot of
I realized this because I was caught in an argument between two views of time. On the one side Julian Barbour, whose ideas on understanding of space and time in relativity theory have been very influential. Nonetheless, I had been unable to agree with his thinking of the last few years, in which he has come to the conclusion that in quantum cosmology time cannot be fundamental. Time, according to him, should play no fundamental role in nature.
But although I instinctively disagree with this, I have been unable to defeat the argument that leads Julian to it. Nor has anyone else. The result is a famous problem in quantum cosmology called the problem of time-time is nowhere to be found in the fundamental equations of the theory.
We have grown so used to the concept of space-time that Einstein brought about that it seems very strange to go back to thinking of just space. But what Barbour is talking about (as far as I can tell) isn't exactly "just space", it's more the "phase space" in which every particle in the universe can potentially take up every possible position - as he says, if there are only 2 particles this gives a 1-dimensional universe, with 3 particles you have 3 dimensions, with 4 six dimensions, and in general with N > 4 you have 3 N - 6 dimensions. For a universe with 10^70 or so particles, we're talking about a 3x10^70 dimensional universe. And it's even worse than that in a sense because the number of particles is not some fixed number, but can itself be any number from 1 to infinity - and it's still worse when you get into the extra dimensions of string theory etc - a very strange space for our universe to live in!
Now how is this actually relevant to reality? Quantum cosmology is still a very speculative field - it may make some testable predictions about black holes, but I suspect there's not going to be much about it we can really experiment with for at least a few hundred, and maybe thousands of years. It's a fun area to play. What does it actually mean that "time is nowhere to be found" in the theories? It either means that what we experience as time is somehow deeply embedded in the configurations of particles in space itself (which is what Barbour seems to be trying to argue) or else it means the theory is wrong or at least incomplete. Personally I'd not be surprised if these theories, elegant as they are, are still incomplete. But it's certainly interesting to discuss the implications if they are right... -
Julian Barbour is NOT a crackpotIHPP (I have a PhD in physics) so I presume I can comment here. A lot of
I realized this because I was caught in an argument between two views of time. On the one side Julian Barbour, whose ideas on understanding of space and time in relativity theory have been very influential. Nonetheless, I had been unable to agree with his thinking of the last few years, in which he has come to the conclusion that in quantum cosmology time cannot be fundamental. Time, according to him, should play no fundamental role in nature.
But although I instinctively disagree with this, I have been unable to defeat the argument that leads Julian to it. Nor has anyone else. The result is a famous problem in quantum cosmology called the problem of time-time is nowhere to be found in the fundamental equations of the theory.
We have grown so used to the concept of space-time that Einstein brought about that it seems very strange to go back to thinking of just space. But what Barbour is talking about (as far as I can tell) isn't exactly "just space", it's more the "phase space" in which every particle in the universe can potentially take up every possible position - as he says, if there are only 2 particles this gives a 1-dimensional universe, with 3 particles you have 3 dimensions, with 4 six dimensions, and in general with N > 4 you have 3 N - 6 dimensions. For a universe with 10^70 or so particles, we're talking about a 3x10^70 dimensional universe. And it's even worse than that in a sense because the number of particles is not some fixed number, but can itself be any number from 1 to infinity - and it's still worse when you get into the extra dimensions of string theory etc - a very strange space for our universe to live in!
Now how is this actually relevant to reality? Quantum cosmology is still a very speculative field - it may make some testable predictions about black holes, but I suspect there's not going to be much about it we can really experiment with for at least a few hundred, and maybe thousands of years. It's a fun area to play. What does it actually mean that "time is nowhere to be found" in the theories? It either means that what we experience as time is somehow deeply embedded in the configurations of particles in space itself (which is what Barbour seems to be trying to argue) or else it means the theory is wrong or at least incomplete. Personally I'd not be surprised if these theories, elegant as they are, are still incomplete. But it's certainly interesting to discuss the implications if they are right... -
From the bleeding edge ...
If people are interested, there's an interview with the author in the ezine Edge. Correct me if I'm wrong, but can someone explain to me what the significance of his interpretation is? Look at it, all I can see is a coordinate transformation from extrinsic linear 3D space to intrinsic circulinear chaos space. I'll try and exaplin with an analogy.
From the measured exterior world, the alpha particle moves in a straight line from the atom. Now from the point of view of the atom, which we can approximate as a spherical point, it can exist in multiple orientations. So if you imagine a sphere spinning randomly around with the number of potential states away from the point the alpha particle split being the linear dimension (ie radius away from sphere), then the alpha particle does appear as a spherical wave.
If there are any physicists out there, can you explain what the significance of what the author is on about? Most people accept that derived order of knowledge is medicine - biology - chemistry - physics - mathematics, but beyond mathematics lies philosophy. For example, if we map the chaotic spherical world to Linux hacker community (a collection of independent free agents) and the extrinsic structured view to the Gartner viewpoint (see previous story) with a single "standard" then you can explain the discrepencies between the 2 points of view. Although the look and feel of Linux is quite variable, it is based on a sonsistent set of principles (file & devices) and based on this framework it is easy to extrapolate to the rest of the world. Thus a Linux hacker, wven when faced with an unknown system, knows roughly where to look for things and can usually ramp up the learning curve fairly quickly. On the other hand, the Gartner worldview only sees the exterior pretty GUI, not understanding that underneath is a mish-mash of concepts and APIs pretending to move in formation. Thus it is a extrinsic view (speaking as a voice for the Fortune500 wannabes) whereas Linux is a multistate intrinsic view with a wavefront of acceptance among individuals that is expanding exponentially. Thus it is fundamentally the difference between single-user (monopole) and multiuser (chaotic wave) disruptive event. If you're an established business interested in saving costs, then a single training interface is considered "superior". If you're a struggling ISP trying to stave off the arrival of the big guns, then having the flexibility to find a niche is more important. Different strokes for different people.
The mindset between the single vs many is also reflected in the difference between the ezines "Edge" and
LL -
From the bleeding edge ...
If people are interested, there's an interview with the author in the ezine Edge. Correct me if I'm wrong, but can someone explain to me what the significance of his interpretation is? Look at it, all I can see is a coordinate transformation from extrinsic linear 3D space to intrinsic circulinear chaos space. I'll try and exaplin with an analogy.
From the measured exterior world, the alpha particle moves in a straight line from the atom. Now from the point of view of the atom, which we can approximate as a spherical point, it can exist in multiple orientations. So if you imagine a sphere spinning randomly around with the number of potential states away from the point the alpha particle split being the linear dimension (ie radius away from sphere), then the alpha particle does appear as a spherical wave.
If there are any physicists out there, can you explain what the significance of what the author is on about? Most people accept that derived order of knowledge is medicine - biology - chemistry - physics - mathematics, but beyond mathematics lies philosophy. For example, if we map the chaotic spherical world to Linux hacker community (a collection of independent free agents) and the extrinsic structured view to the Gartner viewpoint (see previous story) with a single "standard" then you can explain the discrepencies between the 2 points of view. Although the look and feel of Linux is quite variable, it is based on a sonsistent set of principles (file & devices) and based on this framework it is easy to extrapolate to the rest of the world. Thus a Linux hacker, wven when faced with an unknown system, knows roughly where to look for things and can usually ramp up the learning curve fairly quickly. On the other hand, the Gartner worldview only sees the exterior pretty GUI, not understanding that underneath is a mish-mash of concepts and APIs pretending to move in formation. Thus it is a extrinsic view (speaking as a voice for the Fortune500 wannabes) whereas Linux is a multistate intrinsic view with a wavefront of acceptance among individuals that is expanding exponentially. Thus it is fundamentally the difference between single-user (monopole) and multiuser (chaotic wave) disruptive event. If you're an established business interested in saving costs, then a single training interface is considered "superior". If you're a struggling ISP trying to stave off the arrival of the big guns, then having the flexibility to find a niche is more important. Different strokes for different people.
The mindset between the single vs many is also reflected in the difference between the ezines "Edge" and
LL -
From the bleeding edge ...
If people are interested, there's an interview with the author in the ezine Edge. Correct me if I'm wrong, but can someone explain to me what the significance of his interpretation is? Look at it, all I can see is a coordinate transformation from extrinsic linear 3D space to intrinsic circulinear chaos space. I'll try and exaplin with an analogy.
From the measured exterior world, the alpha particle moves in a straight line from the atom. Now from the point of view of the atom, which we can approximate as a spherical point, it can exist in multiple orientations. So if you imagine a sphere spinning randomly around with the number of potential states away from the point the alpha particle split being the linear dimension (ie radius away from sphere), then the alpha particle does appear as a spherical wave.
If there are any physicists out there, can you explain what the significance of what the author is on about? Most people accept that derived order of knowledge is medicine - biology - chemistry - physics - mathematics, but beyond mathematics lies philosophy. For example, if we map the chaotic spherical world to Linux hacker community (a collection of independent free agents) and the extrinsic structured view to the Gartner viewpoint (see previous story) with a single "standard" then you can explain the discrepencies between the 2 points of view. Although the look and feel of Linux is quite variable, it is based on a sonsistent set of principles (file & devices) and based on this framework it is easy to extrapolate to the rest of the world. Thus a Linux hacker, wven when faced with an unknown system, knows roughly where to look for things and can usually ramp up the learning curve fairly quickly. On the other hand, the Gartner worldview only sees the exterior pretty GUI, not understanding that underneath is a mish-mash of concepts and APIs pretending to move in formation. Thus it is a extrinsic view (speaking as a voice for the Fortune500 wannabes) whereas Linux is a multistate intrinsic view with a wavefront of acceptance among individuals that is expanding exponentially. Thus it is fundamentally the difference between single-user (monopole) and multiuser (chaotic wave) disruptive event. If you're an established business interested in saving costs, then a single training interface is considered "superior". If you're a struggling ISP trying to stave off the arrival of the big guns, then having the flexibility to find a niche is more important. Different strokes for different people.
The mindset between the single vs many is also reflected in the difference between the ezines "Edge" and
LL -
Re:Emergent Behavior and Rodney BrooksOops, the link was not quite right...
Also, it is actually on the Edge site mentioned by another poster....