Book Review: Life as No One Knows It: The Physics of Life’s Emergence

What is life and how does one recognize it? asks Walker, an astrobiology professor at Arizona State University, in her bold debut. Defining life is a deceptively tricky endeavor, she argues, noting that the claim popular in scientific circles that “life is a self-sustaining chemical system capable of Darwinian evolution” would mean that worker bees aren’t alive because they can’t reproduce.