Time's Second Arrow

A distinguished geoscientist and rising-star astrobiologist offer a stunning new theory upending 150 years of established science—and an inspiring new vision of our universe.

Of the codified laws of nature, famously, only one inscribes a direction to time: the dreaded second law of thermodynamics, which declares that the disorder of a closed system tends to increase as time passes. New shoes eventually scuff, our bodies weaken and die. Yet our senses tell us that miraculous order constantly emerges, too: children grow and learn; spontaneous patterns manifest in murmurations of starlings. Can it be true that the laws of our universe mandate only dissolution—rendering the intricate order of a butterfly’s wing, the much-vaunted complexity of the human brain, merely incidental?

In Time’s Second Arrow, star scientists Robert M. Hazen and Michael L. Wong overturn more than a century of scientific canon, arguing that, in fact, there must be a second “arrow of time”—a heretofore missing law of nature that explains how the marvelously complex constituents of our universe came to be. Evolution, they boldly propose, is a universal phenomenon—not only in biology, but in the entire atomic, chemical, mineral, and physical universe. Showing how a natural process of selection for increasing function has shaped the universe since its inception, they explore how this new law could possibly help us identify life on other planets and—perhaps—even understand the purpose and meaning of life on Earth in a new way.

Elegantly written and deeply moving, Time’s Second Arrow reveals how our cosmic inheritance includes, even alongside loss and decay, a drive toward wondrous invention and progress—ultimately revising our understanding of the universe and our place within it.