  In the context of his general theory of relativity, what Einstein is objecting to in Newtonian Mechanics, and by implication, the theory of special relativity, is the absolute character of the inertial structure; he is not asserting its fictitious character. That is, the general theory of relativity incorporates Mach’s Principle as expressed in version (1) by treating the inertial structure as dynamical and not as absolute. 