THE STATISTICAL UNIVERSE: BOLTZMANN AND ARROW OF ENTROPY

Everything in the world runs one way. Coffee cools, glass shatters, memory reaches backward and never forward. In the last decades of the nineteenth century one Viennese physicist tried to explain that one-way world using nothing but particles obeying laws that work perfectly well in reverse. He very nearly succeeded, and the way he failed turned out to be more interesting than success. Ludwig Boltzmann gave us the statistical universe: a cosmos described not by tracking what each piece is doing but by counting how many arrangements would look the same from outside. It is the most successful move in the history of physics and also the most expensive. Every version of his argument bought the direction of time by quietly declaring something first, and the declarations were written in a notation that made them invisible. This book opens the accounts. It follows Boltzmann from a tax official's house in Vienna to a chair in Graz at twenty-five, through a running war with philosophers who insisted atoms were a figure of speech, to a grave carrying a formula he never wrote. Along the way it asks the questions his critics asked and nobody has fully answered: where exactly does the arrow of time enter a machinery that has none? What is being counted, and by whom? And since the laws of thermodynamics describe a perfectly sealed system, and no one has ever exhibited one, in what sense have those laws ever been proved at all? >Keywords: Boltzmann, entropy, arrow of time, statistical mechanics, second law of thermodynamics, history of physics, philosophy of science, cosmology