Ernst Mach

Abstract

Ernst Mach (1838–1916) was an influential Austrian physicist and philosopher born in Chrlice (now Brno, Czech Republic). He studied mathematics and physics at the University of Vienna, earning his doctorate in 1860, and subsequently held professorships at the University of Graz, Charles University in Prague, and the University of Vienna. Mach famously challenged the Newtonian concept of absolute space by arguing that inertia must arise from interaction with the rest of the universe, laying critical philosophical groundwork for modern physics.

Mach’s Objection to Absolute Space

Newton defined inertia relative to an absolute, invisible frame. Mach rejected this, arguing that resistance to acceleration must be caused by interaction with other matter in the universe. The famous bucket experiment illustrated the problem: why should rotating water know it is rotating unless it is interacting with something?

Scientific Contributions and Empiricism

Beyond his critique of mechanics, Mach made profound contributions to wave mechanics, optics, and thermodynamics. He studied supersonic motion, defining the ratio of an object's speed to the speed of sound—known today as the Mach number. As a staunch empiricist, he argued that science should exclusively deal with what can be directly observed and measured, heavily influencing the Vienna Circle and logical positivism.

Influence on Relativity

Mach’s critique of absolute space left a deep impression on Albert Einstein during the development of general relativity. Although Einstein later realized that general relativity does not fully embody "Mach's Principle" in the strictest relational sense, Mach's questioning of foundational concepts served as a vital catalyst for the rethinking of space and time.