The Symmetry of Measurement

To meet the requirements of the symmetry implied in the concept of measuring and avoid logical difficulties it is demanded that mathematical expressions used in indirect measurements be valid for reciprocal, as well as direct values of their constituent measurable quantities, while both of those values of every measurable quantity must be established simultaneously in one and the same act of measurement. That means the measurable world must be symmetrical about number one. The problem of the operation of addition and the case of equation a2=b2+c2+kbc are considered. Some immediate consequences are discussed; in particular, the absence of a ruler in the Universe, the quantum character of space-time, a corrected equation for the Doppler effect, etc.