Abstract
The chief object of my paper is to clarify the notion of relativity to the means of observation as the basis for description of physical phenomena. This concept is so important that it deserves the name "the principle of relativity to the means of observation." This principle is particularly important to a correct understanding of quantum mechanics. The notion of relativity to the means of observation is, in a certain sense, a generalization of the notion of relativity to the system of reckoning. The two notions play analogous roles in the corresponding theories. But while relativity theory, which rests upon the notion of relativity to the system of reckoning, takes into consideration only the motion of the means of observation as a whole, in quantum mechanics it is also necessary to take note of deeper properties of the means of observation