The Great Atom Debate

In the late 19th century, two brilliant, stubborn Austrian physicists—Ernst Mach and Ludwig Boltzmann—clashed over whether energy or discrete matter was fundamental to the universe. Mach saw atoms as useful fictions; Boltzmann insisted they were real. Physicist Paul Halpern connects this historic clash to today's debates over what is fundamental, illuminating not just physics' past but the unseen entities playing roles in theories about its future.