Einstein: The Illusionist

What would Einstein answer to this question: Is the time dilation and space contraction of special relativity real physics or only illusionary physics?

Here is his answer published in Physik Zeitschrift 12, p 509, 1911:

• The question whether the Lorentz contraction (time dilation and space contraction) does or does not exist is confusing. It does not really exist in so far as it does not exist for an observer who moves (with the rod); it really exists, however, in the sense that it can as a matter of principle be demonstrated by a resting observer.

This ambiguous answer is typical of Einstein and makes discussion so difficult. One way to interpret Einstein's statement is that time dilation and space contraction are both real and illusionary physics at the same time and one can always choose whatever fits the discussion best. 

If a skeptic says that the physics is contradictory a physicist can say that the contradiction is only an illusion so it is no real contradiction, and if the skeptic complains that it is illusion the physicist can say that this is only a misinterpretation of something which is real physics.

This is why the discussion becomes so confusing, even to Einstein, and all his followers as thousands and thousands of modern physicists.

An example of illusion of contradiction connecting to space contraction, is to consider two twins looking at each other at distance both stating according to physical input that the other appears to be smaller.  Of course you say that the smaller size is only an illusion depending on view at distance and that the twins in fact remain physically equally tall.  

It is like two twins both appearing to age slower than the other which could be an illusion of similar form if the twins are equipped with identical clocks and are traveling with a mutual velocity difference $v$ each one able to record the frequency of the other clock through a light signal subject to Doppler shift scaling with $\frac{1}{1+v}$ with the speed of light normalised to 1. Both twins would then be able to record a redshift when parting and blueshift in approach and state that their instruments record a different rate of ageing. All illusion of course, depending on Doppler shift.

A discussion with Swedish media physicist Ulf Danielson can be followed in comments to the previous post. This is hot topic so follow closely! Is it confusing or illuminating?

Note that Danielson immediately plays the following card suggesting that I am a crackpot representing pseudoscience:

• In a time when theories that the Earth is flat and conspirations around moon landings are flooding the net, it is not so surprising that questions like this (my questions) come up.
• (I en tid när teorier om att att jorden är platt och konspirationer kring månlandningen florerar på nätet tillsammans med pseudovetenskap av olika slag är det kanske inte så överraskande att en fråga av detta slag dyker upp.)

This is one approach to debate. Let us see how effective it is this time. Danielson's professional work concerns string theory, by many viewed today as illusionary physics rather than real physics. This may explain why Danielson is not sensitive to a distinction between illusion and reality, or definition and fact as discussed in previous posts.