A tick, a tock, a swiftly shifting digit. We have many ways of keeping track of time. We parse it into years, months, days, hours, minutes, seconds. We mark its movement obsessively, plan our days around it, use its form to bring meaning to stories with a beginning, middle and end (chronologically is one of our most common ways to organize information).
Cells use time’s rhythms to organize different functions. Precision timing of neurons and muscles, directed by the brain, controls the body’s movements. Time is a tool that brings order to our lives. It is ironic, then, to discover that physicists explain time as a product of disorder: Its forward direction reflects the unalterable tendency to increasing messiness in the universe.