ThingB. The vibrations of a pendulum take place in time when its excursion depends on the position of the earth. Since, however, in the observation of the pendulum, we are not under the necessity of taking into account its dependence on the position of the earth, but may compare it with any other thing (the conditions of which of course also depend on the position of the earth), the illusory notion easily arises that all the things with which we compare it are unessential. (....) It is utterly beyond our power to measure the changes of things by time. Quite the contrary, time is an abstraction, at which we arrive by means of the changes of things; made because we are not restricted to any one definite measure, all being interconnected."These quoted lines show that Mach had clearly recognized the weak sides of classical mechanics, and was not far removed from demanding a general theory of relativity, and this already half a century ago! It is not improbable that Mach should have himself discovered the theory of relativity, if the question of the constancy of the speed of light had pre-occupied the community of physicists when he still had a fresh and youthful mind. Einstein thus hails Mach as one of the great scientists of the era, and within his obituary gives the above passage dealing with the non-existence of time as evidence for why Mach was such a great physicist. Kurt Gödel and Albert Einstein Though the influence of Mach upon Einstein here described by the latter was certainly the most pronounced in the first four decades of his life, it is true that the warmth of Einstein's admiration for Mach cooled considerably after 1921 due to the posthumous publication of a text penned by Mach shortly before the latter's death disavowing any support for the theory of relativity. It must have disappointed Einstein, since we can see from partially extant friendly correspondence between the two that Mach had initially responded positively to the theory of relativity, much to the delight of Einstein. Einstein would later come to view Mach's ideas upon a number of subjects with increasing skepticism, but he never ceased to mention how Mach's work had influenced him and continued to discuss Machian problems and concepts with his close friends and colleagues. One of these friends was Kurt Gödel, who in his works contemplated and examined