“The objective and merit of Einstein's theory is to identify those physical magnitudes which are absolute, i.e. common for all Inertial Frames, distinguishing them from those which are a mere perspective, only shared by those observers in repose within a given Inertial Frame.”

“As we already pointed out, 'special' means 'restricted to Inertial Frames of Reference', i.e. this theory cannot describe the Universe from an arbitrary reference frame. This restricted scope is not to be ignored, though not overemphasized either. ...Ironically, and precisely because of the great success of this simple version of Relativity Theory, most of its detractors have chosen to ignore (out of ignorance or malice -- you judge case by case) its philosophical foundation and restriction to Inertial Frames, so as to declare it invalid.”

“It is worth noting that a wrong folkoric definition of an Inertial Frame in the Popular Science literature (even in text books) reads that 'it is a frame in uniform motion'. We know very well by now that the idea of motion requires a frame of reference, so that such a definition of an Inertial Frame has no meaning whatsoever, confusing the reader because it tacitly reaffirms the idea of absolute motion -- when the goal of every didactic exposition of Relativity Theory should be precisely the opposite.”

“The notion of Local Inertial Frame is crucial to understanding Nature and, in particular, General Relativity. Notwithstanding, very few popular science books (not even textbooks) emphasize enough its fundamental character.”

“Absolute beauty,That which contains all the world's majesty and miseryAnd which is only visible to those who love.”

“It is a good principle in science not to believe any 'fact'---however well attested---until it fits into some accepted frame of reference. Occasionally, of course, an observation can shatter the frame and force the construction of a new one, but that is extremely rare. Galileos and Einsteins seldom appear more than once per century, which is just as well for the equanimity of mankind.”