From: tjroberts137@sbcglobal.net   
      
   On 7/11/18 7:57 PM, Nicolaas Vroom wrote:   
   > On Saturday, 7 July 2018 01:38:32 UTC+2, Tom Roberts  wrote:   
   >> It OUGHT to be clear that NOTHING we observe can be inconsistent   
   >> with the laws of physics -- we and any physical process we observe   
   >> are necessarily constrained by those laws. I did not "set down a   
   >> rule" that is not already contained in the phrase "laws of   
   >> physics".   
   >   
   > First of all identical processes (experiments) have identical   
   > descriptions.   
      
   Not true. In the example discussed in this thread, the train observer   
   describes it as "the stone falls straight down", while the embankment   
   observer describes it as "the stone falls in a parabolic arc". These are   
   different descriptions of a single process, due to the observers'   
   different perspectives.   
      
   You yourself give another counterexample to this claim:   
      
   > Consider a train which travels in a straight line from A to B.   
   > Observer A at A sees the train fading away and becoming smaller.   
   > Observer B at B sees the train awaking at the horizon and becoming   
   > larger.   
      
   That's two different descriptions of a single phenomenon. They differ   
   because they are descriptions from different perspectives.   
      
   > Both tell the truth, but is it the reality? Is the actual train   
   > becoming smaller or larger? No. What you need is one reality, one   
   > world, one reference frame, one coordination system that both   
   > observers agree to use as the basis for all descriptions of all   
   > processes.   
      
   There is one "reality", one world. But trying to single out "one   
   reference frame, one coordinate system" is USELESS -- all are equally   
   valid; they give different descriptions of phenomena based on their   
   different perspectives. We do this ALL THE TIME, and I don't see why you   
   have difficulty with it. Note you CANNOT separate an observer from her   
   perspective; for many cases in physics, "perspective" means "coordinates".   
      
   > That means you need some sort of translation of transformation to   
   > transform the observed (measured) reality to this real reality.   
      
   "Real reality" is a hopeless obfuscation. Henceforth I substitute   
   "world" for your "real reality", as that is the usual word for what you   
   mean. ("World" as distinguished from "model"; more on this below.)   
      
   You cannot avoid the fact that different perspectives of a given   
   phenomenon will yield different descriptions of it. Ditto for   
   "perspective" => "coordinates".   
      
   Note that no physical phenomenon can possibly depend on an observer's   
   perspective or coordinates (nature uses neither), so the physical laws   
   that describe the phenomenon must be independent of both.   
      
   	"Physical laws" is an ambiguous phrase: it can mean the   
   	unknown methods by which nature behaves in the world,   
   	or it can mean the human statements of general models   
   	derived from observations of how nature behaves. But   
   	in order for the latter to accurately reproduce the   
   	former, they must be independent of perspective and   
   	coordinates (for both meanings of "they").   
      
   > This recognition between what we observe (which is observer   
   > dependent) and what actual is, is very important, because it is   
   > observer independent.   
      
   Yes. But every description requires a perspective (coordinates).   
      
   > In [the world] the actual processes take place.   
      
   Yes. Physical processes take place in the world; we humans describe them   
   using a MODEL, and such descriptions inherently require a   
   perspective/coordinates, because that is how we formulate models.   
      
   	Every word we use is not reality, not the world, it is   
   	a thought; those that relate to the world are MODELS.   
      
   One must, of course, distinguish between world and model. This can be   
   cumbersome as our language consists of relating thoughts to each   
   other, and is necessarily bound to models of the world.   
      
   Models are how we humans survive in the world. You cannot find your bed   
   at night without a model of your domicile: you mentally traverse the   
   model from your current location to your bed, and then manipulate your   
   body to follow that path.   
      
   > In [the world] there is also a clear distinction between processes   
   > based on electromagnetic phenomena and gravitational phenomena.   
      
   Nonsense. It is our MODELS that distinguish this. Nature just does   
   whatever she does (which we do not "know", we only model). We have   
   CHOSEN to use different models for gravitation and electrodynamics.   
      
   	There is, of course, much effort being expended in the   
   	search for a "theory of everything", which would   
   	presumably erase this artificial distinction between   
   	these models, and unify their disjoint domains.   
      
   > [...]   
      
   Tom Roberts   
      
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