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One interesting aspect of modelling the universe is that the universe is not a single atomic entity. Speaking of what happens 8 lightyears away from us "right n

by augustl 13y ago

One interesting aspect of modelling the universe is that the universe is not a single atomic entity. Speaking of what happens 8 lightyears away from us "right now" makes no sense - there's no way information 8 light years away can reach us faster than 8 (of our) years, so the shared "now" between us is just theoretical. We can imagine that it's there, but we cannot know what's there, or measure it in any way. The only atomic thing is the way I percieve the universe right now. Someone else will percieve it differently. I'm _not_ talking about the fact that your blue might not be my blue, I'm talking about the fact that time might move at a different pace (if you've accelerated or decelerated) and that you're a long enough distance away from me that our lack of a shared "now" is not negligible in calculations. So a digital model of the universe would have to take into account that the whole universe, again, isn't an atomic entity, and rather model that we have different entities perceiving things as the universe has propagated to their point of view, in their speed of time.

GrantS 13y ago
This is a very person-centered view of the universe, no? We're made of the same fundamental particles as everything else, no need to make special cases for when perception and cognition arise in the universe -- they/we follow the same physical rules as everything else. So as long as you're simulating the right universe (i.e. the laws of physics are the actual laws of physics that we experience), everything you're talking about just happens by definition, right?
- eru 13y ago
  I think augustl just used person-centric language for ease of expression.
- augustl 13y ago
  I should have said "an observer" instead of "I" to make it clearer that I'm talking about any physical observer, not brains and interpretations.
chriswarbo 13y ago
Interestingly this is still related to information: the fundamental thing which cannot travel faster than light is information, for example if I trace a circle in the sky with a laser pointer then the "dot" (when it eventually hits something) will be moving around a vast circle at far faster than light speed, but it cannot send information between the points on the circle so that's fine. Similarly, the effect of measurement ("collapsing the wavefunction") is just a propagation of information from inside the system to outside the system. Actually, it's an increase in the size of the system: first we have an atom that does or does not decay, then we have an atom that does decay and is detected or does not decay and is not detected. Then we have all that along with a vial of poison which is or is not broken. Then we have all that along with a cat that is alive or dead. Then we have a human who sees a living or dead cat. Then we have a paper which reports either a living or dead cat. Then we have a news report about the cat living or dying. And so on. Schroedinger's cat is always in an alive/dead superposition, but at some point that superposition expands (due to information flow) to include an Earth which is in a superposition of knowing it lived or died.
- augustl 13y ago
  I like the term "universal speed limit" better than "speed of light". :)

by augustl 13y ago

GrantS 13y ago

This is a very person-centered view of the universe, no? We're made of the same fundamental particles as everything else, no need to make special cases for when perception and cognition arise in the universe -- they/we follow the same physical rules as everything else. So as long as you're simulating the right universe (i.e. the laws of physics are the actual laws of physics that we experience), everything you're talking about just happens by definition, right?

eru 13y ago
I think augustl just used person-centric language for ease of expression.
augustl 13y ago
I should have said "an observer" instead of "I" to make it clearer that I'm talking about any physical observer, not brains and interpretations.

chriswarbo 13y ago

Interestingly this is still related to information: the fundamental thing which cannot travel faster than light is information, for example if I trace a circle in the sky with a laser pointer then the "dot" (when it eventually hits something) will be moving around a vast circle at far faster than light speed, but it cannot send information between the points on the circle so that's fine. Similarly, the effect of measurement ("collapsing the wavefunction") is just a propagation of information from inside the system to outside the system. Actually, it's an increase in the size of the system: first we have an atom that does or does not decay, then we have an atom that does decay and is detected or does not decay and is not detected. Then we have all that along with a vial of poison which is or is not broken. Then we have all that along with a cat that is alive or dead. Then we have a human who sees a living or dead cat. Then we have a paper which reports either a living or dead cat. Then we have a news report about the cat living or dying. And so on. Schroedinger's cat is always in an alive/dead superposition, but at some point that superposition expands (due to information flow) to include an Earth which is in a superposition of knowing it lived or died.

augustl 13y ago
I like the term "universal speed limit" better than "speed of light". :)