Talk:Time
From Simulism
This is clearly hugely complex, and would present all sorts of conceptual and practical problems for simulist programmers. I would appreciate some discussion of whether the proposed distinction between these times is (a) useful, and (b) valid.
In addition, re-reading this, I am not at all convinced that OIT, IOIT and SIT are all different. I think that these concepts need to be clarified
--TonyFleet 08:37, 25 February 2007 (CET)
Perhaps the stuff on Time Travel should be in a science-fiction category rather than science?
--TonyFleet 12:54, 25 February 2007 (CET)
Possibly; if you want to keep it on the 'time' page though, you can also assign 2 categories to the article. --Ivo 08:57, 26 February 2007 (CET)
[edit] Edits to the Page by Linas
Linas - please note: The convention on this Wiki is that articles like this are left intact, and discussions kept to the talk page.
A programmer would be faced with two choices in this situation: either to make time slow down for the travelling twin, but then this defeats the whole notion of time-dilation; the twin would notice, and declare that relativity is a sham. (The preceeding sentance is wrong, and demonstrates a complete misunderstanding of relativity. Time DOES slow down for the twin; the twin does know this, and can even measure it, but can do nothing about it. This does not mean that relativity is a sham. Please notice that time dilation can be measured as simply as placing an atomic clock on an airplane: the atomic clock on the airplane, when it comes back home, will show that it is a few microseconds younger than its twin. Microseconds are quite easy to measure these days. Furthermore, the author here makes the flawed assumption that computer simulations must inherently live in Euclidean space-time. In fact, special relativity shows that the geometry of space-time is hyperbolic, and the correct geometry to use at this scale would be hyperbolic geometry. There is no particular difficulty with running computer simulations, e.g. "the Sims", in non-Euclidean geometry; one could even run the sims in a 42-space dimensional plus 11-time dimensional universe, instead of the 3+1 space+time universe we are accostmed to. This kind of simulation is possible today, using commonly known mathematics taught in schools today.). On the other hand, and this is the more alarming prospect, we now have a situation where two brains in vats are experiencing different times in the same simulation. One of these is in the future of the other one, and therefore potentially has knowledge of the actions of the other before he or she has acted. This effectively removes any notion of free will. The only way to counter this situation is to suppose that the external consciousness is locked into an individual solipsistic simulation.
comments from Tony
(i) Yes I do understand relativity, but when we use the term 'time slows down' this is a very difficult idea to interpret. In real relativity, if you take the viewpoint of Observer A, who is stationary, then Observer B (travelling) appears to have their time 'slowed down', as one hour for B may last several hours (or years) in A's Terms. To that extent, B's time has 'slowed down'. However, in B's Terms, time carries on at a normal rate. My point about this sequence was as follows. If, in order to ensure that A and B (who, if you read the preceding paragraph in the article are brains in vats and therefore are experiencing an identical subjective flow of time, external to the simulation) can experience the same situation on B's return, a programmer needed to do some adjustment to B's clocks in order to make it appear as if B's time had slowed down, but in fact subjectively, it actually took the same amount of time for B as A, then B would notice and declare that relativity is just an artifact concerning clocks, and not a real phenomenon. What B would say would be "My time, according to my clock, appears to be passing at a very slow rate, compated to what I am subjectively experiencing".
(ii) The Geometry of Spacetime is not currently known. Some theorists have suggested that on the large scaleit is hyperbolic, some have suggested that it might be flat, and many theorists claim that it might be elliptical. Currently we have no way of determining which of these options is the case. What is clear is that Einstein tells us that locally, none of these is the case, and gravitational effects change the geometry of spacetime at each location.
I am not sure how the geometry is relevant to the argument here in any case. I was not actually specifying anything about Euclidean Spacetime other than to say there is no universal time, which is the one feature of relativity which make the whole thing very difficult to programme, unless you either have a solipsistic simulation with lots of zombies, or else the simulation is made up entirely of virtual minds which can have their subjective time manipulated by the programmer. Incidentally UI think the geometry is a red herring, as in a virtual world is programmed you do not need to have any specific geometry at all - we are all used to 'rooms' which lead off to other rooms, or back to themselves. The geometry of most computer games is far more complex than any real world version is likely to be.
--TonyFleet 15:50, 16 July 2007 (CEST)
