3 ms·

I only object your claim that relativity - as in special or general theory of relativity - has any bearing on the design of distributed systems on Earth. In par

I only object your claim that relativity - as in special or general theory of relativity - has any bearing on the design of distributed systems on Earth. In particular, you can order events occurring at different places if you have properly synchronized clocks. The fact that a common solution is to use logical clocks like Lamport clocks is because it is easier to do so than to maintain a network of precisely synchronized clocks. But that does not mean it can not be done with synchronized clocks, see for example Google's Spanner [1] database. I never addressed what else is necessary to make this work in the presence of Byzantine faults. But I am also pretty sure that just sending information about events from A and B to C and asking C about the ordering is not sufficient, after all C may be faulty and give a wrong answer, change its mind after every query, or just not respond at all. Admittedly you did not provide many details, so I may very well totally misunderstand what you had in mind. But, just to repeat, I am not really addressing the requirements of a Byzantine fault tolerant system, I am just saying that the special or general theory of relativity is not relevant for distributed systems on Earth. [1] https://en.wikipedia.org/wiki/Spanner_(database) https://en.wikipedia.org/wiki/Spanner_(database)

EGreg 8y ago
I think you misunderstood my point. I said that relativity is a special case of this principle that time is a local phenomenon.
- danbruc 8y ago
  Which is not really true, time is frame depended, not location depended. Just take the twin paradox, when they start and later meet again, they are in the same place but different amounts of time have passed for each of them. The closest thing I can think of is that the ordering of two events is not ambiguous if they are timelike separated while for spacelike separated events you can find different reference frames which disagree on the order of the events.
  - EGreg 8y ago
    What you said doesn’t disprove what I said :)
    - danbruc 8y ago
      Given that we have never actually defined what »time is a local phenomenon« is supposed to mean, that may or may not be true. But given that relativity puts time and space on a more equal footing than Newtonian mechanics, where you now can turn time into space and space into time, I remain pretty doubtful that something that can be summarized as »time is a local phenomenon« is likely to be interesting and correct because it seems to point in the direction of not treating time and space in a unified manner.
      - EGreg 8y ago
        Listen, space is a local phenomenon too. It is just about correlations. A lot of the nonlocal effects in De Broglie Bohm theory become classical once you consider close-by objects and neighborhoods. They are just super correlated. Why? We don’t know. But with so many correlations, you can compare way more easily between them. https://www.wired.com/2016/01/quantum-links-in-time-and-space-may-form-the-universes-foundation https://www.wired.com/2016/01/quantum-links-in-time-and-spac...
        danbruc 8y ago
        This still does not answer what you mean with »time is a local phenomenon«. What feature of time is local and in which sense? And I am even more skeptical about »space is a local phenomenon«, I mean »local« means »close in space« and therefore it seems you are saying something recursive, i.e. space has some property within itself which doesn't really make sense, at least to me. So unless you can define or at least explain in more detail what you mean with »time (or space) is a local phenomenon«, we won't really get anywhere.

EGreg 8y ago

I think you misunderstood my point. I said that relativity is a special case of this principle that time is a local phenomenon.

danbruc 8y ago
Which is not really true, time is frame depended, not location depended. Just take the twin paradox, when they start and later meet again, they are in the same place but different amounts of time have passed for each of them. The closest thing I can think of is that the ordering of two events is not ambiguous if they are timelike separated while for spacelike separated events you can find different reference frames which disagree on the order of the events.
- EGreg 8y ago
  What you said doesn’t disprove what I said :)
  - danbruc 8y ago
    Given that we have never actually defined what »time is a local phenomenon« is supposed to mean, that may or may not be true. But given that relativity puts time and space on a more equal footing than Newtonian mechanics, where you now can turn time into space and space into time, I remain pretty doubtful that something that can be summarized as »time is a local phenomenon« is likely to be interesting and correct because it seems to point in the direction of not treating time and space in a unified manner.
    - EGreg 8y ago
      Listen, space is a local phenomenon too. It is just about correlations. A lot of the nonlocal effects in De Broglie Bohm theory become classical once you consider close-by objects and neighborhoods. They are just super correlated. Why? We don’t know. But with so many correlations, you can compare way more easily between them. https://www.wired.com/2016/01/quantum-links-in-time-and-space-may-form-the-universes-foundation https://www.wired.com/2016/01/quantum-links-in-time-and-spac...
      - danbruc 8y ago
        This still does not answer what you mean with »time is a local phenomenon«. What feature of time is local and in which sense? And I am even more skeptical about »space is a local phenomenon«, I mean »local« means »close in space« and therefore it seems you are saying something recursive, i.e. space has some property within itself which doesn't really make sense, at least to me. So unless you can define or at least explain in more detail what you mean with »time (or space) is a local phenomenon«, we won't really get anywhere.