137 - Arthur I. Miller [49]
In the light of relativity theory Mach’s view seemed too restrictive. A group of young philosophers with strong scientific backgrounds began to meet in the coffeehouses of Vienna to discuss how to correct this situation, how to bring positivism into line with relativity theory. They called themselves the Vienna Circle and came up with a sophisticated version of positivism that they dubbed “logical positivism.” Then they renamed it “logical empiricism”: the word “empiricism” refers to experimental data (empirical data). Logical empiricism emphasized the role of mathematics in that a theory required a consistent logical or mathematical structure. Mach, on the other hand, regarded mathematics as merely an economical way to summarize experimental data.
In the view of the Vienna Circle a scientific theory had to be built on empirical data with the help of mathematics and had to generate predictions that could be tested in the laboratory. Science was a two-way street, beginning with data and ending with predictions that could be verified by data in the laboratory. Logical empiricism also insisted that every concept in a scientific theory must be measurable. Distance could be measured with a ruler, time by clocks, and so on. Thus they claimed that Einstein’s discovery of relativity theory was actually in accordance with positivism.
As for atoms, this was just a name for a list of experimental results. The rays emerging from cathode-ray tubes—primitive television tubes—were assumed to be a sort of light ray with an electric charge. Actually, every scientist knew that cathode rays were made up of electrons. Both Mach and the logical empiricists declared that atoms were not real as they could not be seen or measured individually. But the logical empiricists were able to see a way around Mach’s rejection of Einstein’s theory of the relativity of time in that it emerged from a consistent mathematics and experiments had been done to illustrate it in the laboratory. Mach’s philosophical heirs made the important point that the criterion “to observe something in the laboratory” had to be replaced by “to ascertain it or measure it in the laboratory.”
Pauli was well read in philosophy and introduced himself to the then-doyen of the Vienna Circle, the German-born Moritz Schlick. Schlick was twice his age and an esteemed professor at the University of Vienna, where he had taken over Mach’s position. Schlick was impressed with Pauli’s philosophical acumen. Pauli did not let the fact that he was a mere postdoctoral student hinder him from giving Schlick his blunt assessment of positivism. He had no objection to it, he wrote in 1922, “But, of course, it is not the only [philosophical approach].”
Indeed it was not. With the rise of psychoanalysis scientists began to look into how they had come up with their discoveries. Einstein wrote, “There is no logical path to these laws; only intuition, resting on sympathetic understanding of experience, can reach them.” In this way, he added, scientists could glimpse the “pre-established” harmony of the universe. Logical empiricists, however, saw this as aimless babble conjured up by scientists years after the fact.
In their view scientists constructed theories by moving logically—mathematically—from experimental data to a theory. They churned out equation after equation until they had solved the problem at hand. Einstein considered this wrongheaded. Scientists were unanimous in agreeing that their methods of research bore no resemblance to the proposals of positivists