Time's Second Arrow Evolution, Order, and a New Law of Nature

By: Robert M. Hazen, Michael L. Wong

Published by W. W. Norton, Incorporated, 2026-02-10

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.