--- On Sat, 1/2/10, archytas <[email protected]> wrote: ... In his analysis of simultaneity, Einstein > considers a > situation in which a light ray is sent (in vacuo) from > point A to > point B where it is then reflected back to A. He remarks > that by > definition we set the time required for the light to travel > from A to > B equal to the time required for the light to make the > return trip > from B to A. This is an astonishing move to make. He says, > in effect, > that we are free to stipulate, as a definition, that the > speed of > light on the trip out is equal to the speed of light on the > return > trip. ============== G: Where and what for does he say that? Please, quote. What are "points" A,B? Are they referentials? Inertial, or not? Are they moving or accelerating with respect to one another? And, anyway, what could that possibly prove or imply?
Further, you keep on talking about "one way light speed", but did not answer my comment: *** "measuring the one way speed of light" is misunderstanding of SR and silly falling back on Galilean Relativity and Aether. Or, maybe I got it wrong? You mentioned it, so please, explain what you mean by it and what new, if anything at all, does it bring. *** I still consider it as ignorant, dilettante bullshit, but perhaps you could tell me something which I overlooked. Cheers, Georges =============== >From the standpoint of classical physics, as well as > simple > common sense, it would seem that the equality (or > inequality) of the > speeds in the two opposite directions is a fact of nature. > If it is a > fact of nature, it must be ascertained empirically, not > laid down in > the form of a definition. This controversy over the one-way > speed of > light is an excellent testing-ground for a number of > philosophical > doctrines concerning conventionality. I’m not > questioning the science > per se and lack the grok to do so. > There is an important tradition-associated with Mach, > Poincare, > Einstein, and many others-which considers as in-dispensable > to > physical understanding the careful philosophical analysis > of such > concepts as mass, distance, space, time, and motion > (Georges, unless > I’m very wrong, makes much of this). An investigation of > the status of > the one-way speed of light (or whatever query we can come > up with), as > fact or convention, can be pursued in the same spirit. How > deeply can > we claim to understand the physical, even if we are using > this word as > short-hand, if this concept suffers central logical > unclarity? Current > scientific developments suggest a further reason for > concern about the > speed of light. As science progresses, it sometimes becomes > advisable > to adopt new conventions regarding fundamental physical > magnitudes. > The wave-length of light in an atomic spectral line has > replaced the > standard meter bar as the basic standard of length, and > atomic > frequencies have replaced astronomic time standards. > Further changes > have no doubt occurred – I’m out of date. An attractive > alternative is > to give up length as a fundamental physical magnitude, > replacing it > with the speed of light as a defined quantity. A distance, > a meter for > example, would then be a derived magnitude - the distance > traversed by > light in a given amount of time. Time and velocity would > thus replace > the traditional basic quantities of time and distance. If > such a > change is made in the foundations of physics - the physics > used by > real-life physicists who make actual measurements in the > laboratory > and the world - it would be good to know whether this new > fundamental > constant is a one-way or a round-trip speed. The > basic defined > quantity would be the average round-trip speed of light. An > additional > definition would equate the two one-way speeds. > My physics is poor – just what a poor chemist gleans from > chats with > colleagues, perhaps leading to revisions of his dumb > experiments with > matter in his common sense on realising if they worked the > radiation > energies would kill everyone in the lab. This is not > my point, nor do > I expect to undermine a subject I barely grasp. I’m > simply trying to > say that some of our reasoning is not about certainty and > that > recognising and shaking conventions about can help us > learn. My > applications of this would be in the dumb world of > soaked-up idiocy > and skilled incompetence masquerading as sense. > An example like this might be used to improve someone's > grok of SR, > something like it might undermine the same. There was > enough in this > example for experiments to be designed and conducted. > There is > learning in the thinking and too much learning is prevented > by those > who discourage daring, impudence or do not have the time to > explain > why a daft question can be shown to be so. > > > On 1 Jan, 09:24, Georges Metanomski <[email protected]> > wrote: > > --- On Fri,measuring the one way> speed of light > 1/1/10, archytas <[email protected]> > wrote: > > ... > > > The point is whether other explorations are > possible, as I > > > suggest > > > they are through reasonable thought even where > great minds > > > have > > > produced theory such as SR which has had great > empirical > > > confirmation. Thinking about measuring the one > way > > > speed of light in > > > vacuum is one such example. > > > > =========== > > G: > > 1.SR is an approximation of GR, like Newton was of > SR. > > 2."measuring the one way speed of light" is > misunderstanding of SR and > > silly falling back on Galilean Relativity and Aether. > > Or, maybe I got it wrong? You mentioned it, so please, > explain what you > > mean by it and what new, if anything at all, does it > bring. > > Cheers, > > Georges. > > -- > > You received this message because you are subscribed to the > Google Groups "Epistemology" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/epistemology?hl=en. > > > -- You received this message because you are subscribed to the Google Groups "Epistemology" group. To post to this group, send email to [email protected]. 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