(A) If two clocks are in relative motion, either clock is slow as judged from the other clock's system.

The conclusion is absurd. It implies that, if two clocks are initially stationary and synchronized but then move relative to one another, in an encounter between them either clock will find the other lagging behind. So if Einstein had stated the conclusion explicitly in 1905, Max Planck would not have found courage to publish his paper.

It took Einstein more than a decade to find good ways to camouflage the absurdity. In 1905, however, he was still ideologically inexperienced and resorted to a blatant lie. Instead of the valid deduction (A), he implicitly advanced the following non sequitur:

(B) If two clocks are in relative motion, the moving one is slow and the stationary one is fast.

Here is the fraudulent text:

Albert Einstein, On the Electrodynamics of Moving Bodies, 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." http://www.fourmilab.ch/etexts/einstein/specrel/www/

If Einstein had obeyed logic and had performed a valid deduction, the text would have been equivalent to this:

On its arrival at B the clock moved from A to B lags behind the stationary clock only as judged from the stationary clock's system. As judged from the moving clock's system, however, on its arrival at B, the clock moved from A to B is AHEAD of the stationary clock.

It is easy to see that the valid deduction, (A), doesn't, but the non sequitur, (B), does predict TIME TRAVEL INTO THE FUTURE - the miracle that converted Einstein into a deity:

"The paradigm of the special relativistic upheaval of the usual concept of time is the twin paradox. Let us emphasize that this striking example of time dilation proves that time travel (towards the future) is possible. As a gedanken experiment (if we neglect practicalities such as the technology needed for reaching velocities comparable to the velocity of light, the cost of the fuel and the capacity of the traveller to sustain high accelerations), it shows that a sentient being can jump, "within a minute" (of his experienced time) arbitrarily far in the future, say sixty million years ahead, and see, and be part of, what (will) happen then on Earth. This is a clear way of realizing that the future "already exists" (as we can experience it "in a minute")." http://www.bourbaphy.fr/damourtemps.pdf