Mach, Ernst

(1838–1916)

   A physicist and philosopher, Mach had a profound influence on Austrian science and culture generally. His teaching career at the University of Vienna was relatively brief, beginning in 1895 but severely curtailed by a serious stroke that he suffered three years later. Nevertheless, his work as a professor in both Graz, where he had lectured in mathematics, and Prague, where he had taught physics, had established him as an authority in both fields. Mach’s experiments in ballistics, for which he used photographs of projectile bullets, demonstrated that these objects created not one but two shock waves when they exceeded the speed of sound. The ratio between the speed of sound and airflow velocity, the so-called Mach number, is now used to determine the speed of supersonic airplanes. Mach deeply respected the scientific revolution of the 17th and 18th centuries for having purged study of the physical world science of what he believed to be misapplied notions of God, nature, and the soul. Nevertheless, he thought that these early experiments had not gone far enough. All true science, he argued, had to be reduced to formulae of measurement. Mach had little patience with what he called “pictorializations” such as atoms and ether, terms common in 19th-century scientific discourse. He took considerable pleasure in exposing false hypotheses in mechanics, optics, and acoustics held by his predecessors. Indeed, his research in this vein led him to be a pioneer in the history of science.

   Mach discounted theory of any kind, be it in physics or psychology. There is no more basis for accepting the ego as part of human psychic makeup than there is for accepting the a priori existence of number. The only knowledge of the world comes from our sensations and the stimuli they provoke. Man is therefore awash in an ocean of appearances that intellect can certainly analyze, order, and even remember, but cannot establish their irreducible reality.