Einstein's original absurdity:

http://www.fourmilab.ch/etexts/einstein/specrel/www/
ON THE ELECTRODYNAMICS OF MOVING BODIES, A. Einstein, 1905: "From this there ensues the following peculiar consequence. If at the points A and B of K there are stationary clocks which, viewed in the stationary system, are synchronous; and if the clock at A is moved with the velocity v along the line AB to B, then on its arrival at B the two clocks no longer synchronize, but the clock moved from A to B lags behind the other which has remained at B by tv^2/2c^2 (up to magnitudes of fourth and higher order), t being the time occupied in the journey from A to B."

Einstein's conclusion, "the clock moved from A to B lags behind the other which has remained at B", is invalid - it does not follow from Einstein's 1905 postulates. The valid conclusion (which does follow from the postulates) is:

(A) The clock moved from A to B lags behind the other which has remained at B, AS JUDGED FROM THE STATIONARY SYSTEM.

There is a second valid conclusion which contradicts the first:

(B) The clock which has remained at B lags behind the clock moved from A to B, AS JUDGED FROM THE MOVING SYSTEM.

Clearly (A) and (B) are incompatible, which means that the underlying premise, Einstein's 1905 constant-speed-of-light postulate, is false.

Pentcho Valev