Comments on Soul Physics: 1907 Crisis in Mathematical Physics According to P...

No problem Stefan -- thanks for the reminder about...

2010-03-15T19:03:02.352-04:00

No problem Stefan -- thanks for the reminder about it!

Hi Bryan, thanks for digging out the Poincaré pa...

2010-03-15T18:50:10.854-04:00

Hi Bryan,

thanks for digging out the Poincaré paper "Sur la dynamique de l'electron"- It's amazing that it is available online now, I have been looking for it for years!

Haha -- indeed, wires must have been crossed. Than...

2010-03-11T09:17:24.393-05:00

Haha -- indeed, wires must have been crossed. Thanks. Corrected.

Bryan, Is the reference to Laplace in point 5 sup...

2010-03-11T09:11:03.589-05:00

Bryan,

Is the reference to Laplace in point 5 supposed to be to Poincare? I thought Laplace died long before Madam Curie fiddled around with radium.

Thanks for the correction Stefan -- the original p...

2010-03-10T16:41:51.632-05:00

Thanks for the correction Stefan -- the original publication seems to have been published in 1905, which explains the lack of Einstein references. (I suppose Popular Science readers were just a bit behind the times.)

Great point about the work of Poincaré on retarded Newtonian gravity. Poincaré published on this in 1905, the same year of this article -- see Section 9 here (Springer PDF) or here. This is a more likely explanation of his beef with special relativity in crisis 2: If you replace the fixed mass terms in Newtonian gravitation with their relativistic counterparts, you don't get an accurate description of planetary orbits. However, some still argue that a more sophisticated kind of relativistic Newtonian gravity is still possible, so the two theories may yet be compatible.

I am not so sure what to make of the date of 1907....

2010-03-10T15:33:06.477-05:00

I am not so sure what to make of the date of 1907. It could just be "fin de sciècle" crisis as well.

"La Valeuer des la Science" has been published in several editions, and it is not clear to me on which one the translation is based. So, one should be careful when trying to put the text into historical context. For example, it may mean nothing special that Einstein is not mentioned.

I have heard a few times that Poincaré did show that implementing retardation into Newtonian gravity is incompatible with the stability of planetary orbits - obviously relevant to crisis 2 - does anybody know some details about this?

Moreover, that electromagnetic fields may have inertia was proposed before Einstein (ask your favourite Einstein denier ;-)...), so this fits well to the crises 4 and 5...

This is just such an interesting passage. Poincaré...

2010-03-10T08:13:31.861-05:00

This is just such an interesting passage. Poincaré apparently didn't understand that superluminal signaling is not prohibited by the postulates of special relativity. That's an extra and unnecessary interpretive assumption (as was recently discussed). You actually can consistently formulate Newtonian gravity -- and obviously quantum theory as well -- on a relativistic background spacetime. Of course, such signaling is conceptually weird in relativity theory -- for example, it means that in certain frames, a signal can propagate backwards in time. But it's not incompatible, as Poincaré suggests.

It may not have been unreasonable for Poincare to ...

2010-03-10T07:11:52.098-05:00

It may not have been unreasonable for Poincare to doubt Einstein's conventional prohibition on superluminal signaling concerning universal gravitation. In some ways, this was partly why Einstein had to go onwards to General Relativity. Of course, this doesn't take into consideration future concerns over faster-than-light movement from the Quantum realm.