Conceive being in an elevator in deep space, not accelerating, and sufficiently distant from gravitational convergence centers to approximate an inertial reference-frame. Under current modes of analysis, whether the elevator has velocity or not is not determinable from within. For the argument we shall presume that in this elevator reference-frame the laws of inertial physics are valid (recognizable). You judge that you are weightless. Next imagine that you move toward one end of the elevator with acceleration g (still under the laws of inertial physics). You are then asked to decide whether the elevator is in acceleration or in deceleration. It should be clear that you have no means for deciding from inside the elevator, using the Newton model or the Einstein model (Special Relativity). Within reasonable limits you may determine g but the decision problem remains. These two cases are dual in their coherence and therefore one is not simpler then the other. This paper argues that this non-decidability in inertial reference-frames cannot be eliminated even with another observation point without making ad hoc assumptions that beg the question. In effect, Einstein's argument introduces pseudoforces.