Most of the questions are explained in the presentation linked in the text 2014-11-08 22:46 GMT+01:00 John Clark <[email protected]>:
> On Sat, Nov 8, 2014 Alberto G. Corona <[email protected]> wrote: > > > The arrow of time is defined by the increase of entropy >> > > No, increasing entropy is not sufficient to establish a arrow of time, as > I've said it can explain why Entropy will be higher tomorrow but by using > the exact same logic Entropy should have been higher yesterday than today > too, but clearly that is nonsense. > > To see how that is true consider all the logically possible microstates of > Alberto Corona that would produce the macrostate that both you and I would > recognize as Alberto Corona, the vast majority of those microstates must > have evolved from high entropy states because they outnumber the low > entropy ones by an astronomical (too weak a word but I don't know of a > stronger one) number. But nobody thinks that is really true, and yet it is > undeniable that you just can not deduce a asymmetry in time from > thermodynamics or from any of the known laws of physics; this dichotomy is > sometimes called Loschmidt's Paradox or Loschmidt's Objection. > > >> > because that is the only direction in which life can operate. >> > > I don't see why that would be true. If the arrow of time were reversed > intelligent beings would just discover different laws of thermodynamics. > They would remember that in the distant future, that is to say a long way > from your "now", perfume molecules "were" (the most difficult part of of > reverse time thought experiments is the grammar) evenly distributed > throughout the room, and they would remember that in the more recent future > the molecules were only in the lower right part of the room, and they would > remember that in the very recent future (very close to your "now") all the > molecules were confined inside one small perfume bottle. They would then > conclude that entropy always decreases or remains the same. > > And as to how the bottle got into that room in the first place.... well, > you can make educated guesses but essentially the only way to know for sure > what the past was like is to wait and see. . > > But the deepest question isn't why time points in one direction rather > than the opposite direction but why it points in any direction at all. > After all the fundamental laws of physics are time reversible, if I show > you a film of non-macroscopic things you can't tell if the film is running > forward or backwards with the electrical charges reversed and the scene > photographed in a mirror. Even the laws of logic are reversible; if I gave > you line 9 of a valid proof in pure number theory you could deduce both > what line 10 must be and what line 8 must have been. So why do we perceive > that time has a preferred direction? > > If the arrow of time doesn't come from physical law it must come from the > initial conditions and we need to add a past hypothesis, that is in the > distant past for some reason entropy was much lower than it is today. > > John K Clark > > > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > -- Alberto. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
