Alive

The Hidden Intelligence of the Living World

By: Melanie Challenger

A major work of interdisciplinary nonfiction that redefines how we understand life, agency, and intelligence

What does it mean to be alive? The slow contortion of a plant toward light, the dive of hawks toward their prey—these are purposeful actions. But where does that purpose come from, and what does it tell us about who we are?

In Alive, natural philosopher Melanie Challenger draws on biology, philosophy, physics, ecology, and the history of science to reveal a radical truth: to be alive is first and foremost a way of being in a body. From Greenland sharks that can live for half a millennium, to birds that sense the Earth’s magnetic field through their retinas, and even slime molds that solve mazes, this book tells a new story of intelligence in the living world.

A scientifically grounded challenge to the idea that life is either a machine run by genes or an essence separable from the body, Alive restores agency, purpose and meaning to organisms in an age of artificial intelligence and biodiversity loss. By recognizing that our bodies are both how and why we are alive, this book asks what it would mean to live—and to act—with that knowledge.

Critic reviews

Advance Praise for Alive:

"The difference between not-alive and alive is perhaps the universe’s biggest mystery. If like me, you’ve wondered what aliveness is, how it happens, why it works and how it takes charge of itself. In Alive, Melanie Challenger has worked her magic to enlighten us in this extraordinary expedition into life itself."
—Carl Safina, PhD; author of Alfie and Me

"For centuries western thought has been corralled by a particular notion of what life is, one that takes its model from machines. . . . Enter renowned naturalist and bioethicist Melanie Challenger, whose new book, Alive, turns this way of thinking on its head. Written with equal parts wit, eloquence, and erudition, Alive introduces us to a world teeming with agents, each one inseparable from its embodied form, and all united by the quality shared by all life: to define its own purpose and find ways to fulfill it."
—William Egginton, author of The Rigor of Angels

"Alive is a profound, provocative and moving meditation on the question of what makes living organisms so special and remarkable. By insisting that life is not an abstract but rather an embodied property, Melanie Challenger offers a vision of the living world that can restore to it the wonder and reverence it deserves."
—Philip Ball, author of How Life Works

"In this beautifully written and awe-inspiring book, Melanie Challenger celebrates the brilliance of Aristotle’s view of life as embodied, bringing it to the forefront of current scientific knowledge and beyond. Yet she goes further, inspiring us to face dying as an inescapable gift of having lived, and, in so doing, teaching us the value of living purposeful lives.”
—Marcelo Gleiser, author of The Dawn of a Mindful Universe

"Alive hits like a shock to the body: bracing and brilliant. Melanie Challenger is an alert and fascinating guide through tricky terrain, leading us from ancient philosophical academies to cutting-edge biology labs to make a startling argument about what it is to live and what it means to be alive."
—Jonathan Blake, author of Children of a Modest Star