If every dynamic variable in a physics problem is a measurement derived from a particular coordinate system how do you explain the contradiction both statements 1 and 2 imply if they are both simultaneously true: 1. According to relativity (relative velocity etc.) every measurement of position, distance, displacement, velocity and acceleration is dependent on the particular coordinate system used to make the measurements and by that logic every observer should get a different measurement based on the particular coordinate system used (i.e. placement of origin and orientation of axes) 2. According to transformation laws and tensor analysis vectors and scalars are covariant or form invariant and therefore measurements do not depend on the particular coordinate system used and by that logic every observer should get the same measurement regardless of their particular frame of reference Unless I have grossly misunderstood physics and how we acquire information about the world (which is more than likely the case) there seems to be a major contradiction here. Correct me if I am wrong please because I do not see a way out of this conundrum!!!