Einstein by Philipp Frank Page B

critics, we may mention Gustav Kirchhoff, the discoverer of spectral analysis. In 1876 he stated that the task of mechanics was “to describe completely and as simply as possible motions occurring in nature.” This meant that Newtonian mechanics is itself only a convenient scheme for a simple presentation of the phenomena of motion that we observe in daily experience. It does not give us an “understanding” of these occurrences in any other philosophical sense. By thus contravening the general opinion that Newton’s principles of mechanics are self-evident to the human mind, he created something of a sensation among natural scientists and philosophers.
    Furthermore, with Kirchhoff’s conception that mechanics is only a description of the phenomena of motion, the mechanical explanations of the phenomena in optics, electricity, heat, etc. — the aim of mechanistic physics — became simply descriptions of these results in terms of a pattern that had been found to be most suitable for mechanics. Why should one describe by this roundabout method of using mechanics instead of trying to find directly the most suitable scheme for the description of various phenomena? Newtonian mechanics was thus deprived of its special philosophical status.
    In 1888 Heinrich Hertz discovered the electromagnetic waves,which form the basis of our modern wireless telegraphy and radio, and he then set out to explain these phenomena in terms of a physical theory. He took as his starting-point Maxwell’s theory of electromagnetic fields. James Clerk Maxwell had derived his fundamental equation from mechanistic physics by assuming that electromagnetic phenomena are actually mechanical oscillations in the ether. Hertz noticed that in doing this Maxwell had been compelled to invent mechanisms that were very difficult to calculate, and found it was simpler to represent electromagnetic phenomena directly by means of Maxwell’s equation between electric and magnetic fields and charges. Since it was also evident to him, however, that these relations could not be derived directly from experience, he was led to a consideration of the logical character of these equations. In 1889 he made a remark that can be regarded as the program for the new approach to physics, a conception that was eventually to replace the mechanistic view. Hertz said:
    “But in no way can a direct proof of Maxwell’s equations be deduced from experience. It appears most logical, therefore, to regard them independently of the way in which they had been arrived at, and consider them as hypothetical assumptions and let their plausibility depend upon the very large number of natural laws which they embrace. If we take up this point of view we can dispense with a number of auxiliary ideas which render the understanding of Maxwell’s theory more difficult.”
    Thus Hertz consciously abandoned that which during both the organismic and the mechanistic period was described as the “philosophical” foundation of physics. He maintained that it was sufficient to have a knowledge of laws from which phenomena could be calculated and predicted without raising any question of whether these laws were intrinsically evident to the human mind.
     
8.
Ernst Mach: The General Laws of Physics Are Summaries of Observations Organized in Simple Forms
    The criticisms of the mechanistic philosophy by physicists such as Kirchhoff and Hertz were only occasional and aphoristic. There were others, however, whose criticisms werebased on a very precise conception of nature and of the task of science. The French philosopher Auguste Comte advanced the sociological theory that the “metaphysical” stage in the development of a science is already succeeded by a “positivistic” one. This means that the demand for the use of a specific analogy such as the organismic and mechanistic views is abandoned and after that a theory is judged only as to whether it presents “positive” experience in a simple, logically