Ernst Mach, Austrian physicist and philosopher (d. 1916)
Ernst Waldfried Josef Wenzel Mach ( MAHKH, German: [ɛʁnst ˈmax]; 18 February 1838 – 19 February 1916) was a Moravian-born Austrian physicist and philosopher, who contributed to the physics of shock waves. The ratio of one's speed to that of sound is named the Mach number in his honour. As a philosopher of science, he was a major influence on logical positivism and American pragmatism. Through his criticism of Newton's theories of space and time, he foreshadowed Einstein's theory of relativity.