If there is maximum speed in the universe and we call it c, and it is not relative, is there also some ultimate rest state, an unrelativistic "0" speed? I sort-of know that there is none, because it would mean that there exists a non-relativistic frame of reference. But I can't quite grasp what is wrong with the following reasoning. Let's start with the twin paradox. One of them has been accelerated and it makes the difference, non-inertial frame of reference was involved. So far so good. If the accelerated twin moved, say, with near-light speed, and he looked back at a clock on his twin's wrist, it would be ticking really fast, right? So. Can I draw the conclusion that the faster the clock goes, the less accelerated that object had been? Why/why not? Using this observation, can we determine that some hypothetical object has never been accelerated? That it has a minimum speed, as opposed to the maximum speed of light?