Timeline for In a "universe" where time runs backwards, is cause/effect preserved?
Current License: CC BY-SA 3.0
11 events
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| Dec 16, 2016 at 20:21 | comment | added | Eric O | I realize that the question is more about semantics and/or epistemology than physics. Since asking the question, I have learned a lot about the "arrow of time" and apparently most of physics is time-direction-invariant (negative time works symmetrically) with the exception of the second "law" of thermodynamics (although I wonder, since there is an implicit time basis to the act of proceeding from order to disorder, if it is a circular argument that assumes positive time). My question is about whether the notion of cause and effect is invariant. | |
| Dec 16, 2016 at 6:50 | answer | added | Bob Bee | timeline score: 3 | |
| Dec 16, 2016 at 0:53 | answer | added | Szymon | timeline score: 0 | |
| Dec 15, 2016 at 23:56 | answer | added | sintetico | timeline score: 0 | |
| Dec 15, 2016 at 23:18 | comment | added | Eric O | Yes I think Loschmidt's Paradox applies, if I understand it to mean that if time ran in the negative direction, it would be, mirror-like, imperceptible (indiscernible?) to inhabitants of that universe. So it may require an external observer in a "time-positive" universe to notice. It is obviously just a thought experiment about observation. | |
| Dec 15, 2016 at 23:02 | comment | added | ACuriousMind♦ | What, exactly, does "time runs backwards" mean here? Are you trying to pose a Loschmidt's paradox-like scenario? | |
| S Dec 15, 2016 at 22:35 | history | suggested | sintetico |
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| Dec 15, 2016 at 22:25 | review | Suggested edits | |||
| S Dec 15, 2016 at 22:35 | |||||
| Dec 15, 2016 at 22:24 | comment | added | sintetico | Well it is an interesting question and I think the answer is not that straightforward. This is related with the thermodynamical arrow of time. However, if one considers only reversible processes or few particle physics (that is, in any case one can forget about the 2nd principle) the answer is definitely yes, the cause and effect is preserved. | |
| Dec 15, 2016 at 22:14 | review | First posts | |||
| Dec 15, 2016 at 22:32 | |||||
| Dec 15, 2016 at 22:12 | history | asked | Eric O | CC BY-SA 3.0 |