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Relativity is not the same as relativism. Theory of relativity gives us a precise description of the relation between A and B... it's just not the kind of relat

Relativity is not the same as relativism. Theory of relativity gives us a precise description of the relation between A and B... it's just not the kind of relation we would naively expect. But we can still calculate the answer from the perspective of any reference frame. (Also, it is possible to have other events C and D such that C happened before D in every reference frame.) Instead of living in a 3D universe with an absolute time, we are living in a 4D universe where time is a relative direction in the space-time. That doesn't mean we can't model things in principle, it just means we need to model them as things existing in 4D space-time.

bschmidt1 2y ago
> Relativity is not the same as relativism True, really just meant "not absolute". > such that C happened before D in every reference frame If that's possible, considering the seemingly infinite number of instances where it'd have to both happen and in that way/order, I would consider those kinds of events to be the fundamental/baseline "forces" or asymmetries.
- Viliam1234 2y ago
  The keywords related to this are "spacelike" and "timelike". https://en.wikipedia.org/wiki/Causal_structure https://en.wikipedia.org/wiki/Causal_structure For example, the distance between Earth and Moon is about 1.3 light-seconds. That means that is A happens on Earth now, and B happens on Moon 1 second later (from our perspective), it is possible that from someone else's perspective B happened before A. (Note that "someone else" in this example does not refer to the Moon, because its perspective is very similar to the perspective of the Earth. It refers to a hypothetical alien spaceship flying at an extremely high speed in a line parallel to the line between the Earth and the Moon.) However, if C happens on Earth now, and D happens on Moon 2 seconds later (from our perspective), then C happened before D from everyone's perspective. Individual aliens would disagree on the exact time interval between C and D, where 0.7 would be the smallest possible value, but it could be any larger value. (You get the smallest possible value when you are not moving relatively to the Earth and the Moon.) This is because a hypothetical light particle emitted at A couldn't reach B in time, but a hypothetical light particle emitted at C could reach D in time. The speed of light is the speed of causality, kind of. Events A and B couldn't possibly have caused each other (they could have a common cause X, but that's different), but C hypothetically could have caused D, which is why C happened before D from everyone's perspective.
  - bschmidt1 2y ago
    > because a hypothetical light particle emitted at A couldn't reach B in time Fascinating insights - it can be seen as causality, or at scale that there is a multi-dimensional reality where some timelines are inaccessible/impossible to each other (yet exist in their own right).

bschmidt1 2y ago

> Relativity is not the same as relativism True, really just meant "not absolute". > such that C happened before D in every reference frame If that's possible, considering the seemingly infinite number of instances where it'd have to both happen and in that way/order, I would consider those kinds of events to be the fundamental/baseline "forces" or asymmetries.

Viliam1234 2y ago
The keywords related to this are "spacelike" and "timelike". https://en.wikipedia.org/wiki/Causal_structure https://en.wikipedia.org/wiki/Causal_structure For example, the distance between Earth and Moon is about 1.3 light-seconds. That means that is A happens on Earth now, and B happens on Moon 1 second later (from our perspective), it is possible that from someone else's perspective B happened before A. (Note that "someone else" in this example does not refer to the Moon, because its perspective is very similar to the perspective of the Earth. It refers to a hypothetical alien spaceship flying at an extremely high speed in a line parallel to the line between the Earth and the Moon.) However, if C happens on Earth now, and D happens on Moon 2 seconds later (from our perspective), then C happened before D from everyone's perspective. Individual aliens would disagree on the exact time interval between C and D, where 0.7 would be the smallest possible value, but it could be any larger value. (You get the smallest possible value when you are not moving relatively to the Earth and the Moon.) This is because a hypothetical light particle emitted at A couldn't reach B in time, but a hypothetical light particle emitted at C could reach D in time. The speed of light is the speed of causality, kind of. Events A and B couldn't possibly have caused each other (they could have a common cause X, but that's different), but C hypothetically could have caused D, which is why C happened before D from everyone's perspective.
- bschmidt1 2y ago
  > because a hypothetical light particle emitted at A couldn't reach B in time Fascinating insights - it can be seen as causality, or at scale that there is a multi-dimensional reality where some timelines are inaccessible/impossible to each other (yet exist in their own right).