Review: Life’s Edge

Life’s Edge: The Search for What It Means to Be Alive, Carl Zimmer. New York: Dutton, (forthcoming) 3/9/2021.

Summary: An exploration of how scientists attempt (and have failed) to define what life is and the quest to understand how life arose.

Philosophers talk about the meaning of life. Carl Zimmer offers us a glimpse into the world of scientists who are trying to define what is life. What is the definition of life and when can something be defined as alive? What about particles like viruses and prions that appear dead until they interact with other living matter? And how did life originate here, and has it in other places in our solar system and beyond?

Zimmer takes us on an exploratory tour of this question that begins in the Cavendish Laboratory in 1904 with John Butler Burke who believed he had created the missing link between inorganic and organic life when he released grains of radium into a sterile broth and discovered under a microscope that shapes were there and were dividing. He called them radiobes and he believed that the radium provided the “vital flux” to turn the constituent elements into blobs of protoplasm. Eventually, he was disproven by other scientists after enjoying fleeting fame.

Zimmer takes us through the history of research on life from van Leeuwenhoek’s discoveries of microscopic life, to the growth of neural networks in laboratories. We go with him to pools near the mouths of volcanoes where some think organic life developed to discussions with researchers studying vents in the ocean. We enter caves to learn of the homeostatic relationship between hibernating bats and parasites who live off them and can kill them if they draw too much energy from the bat. We read of research demonstrating the lifelessness of soil samples on Mars and a meteorite from Mars that may evidence signs of life. I learned that red blood cells have no chromosomes and cannot divide and multiply like other cells.

Zimmer recounts the efforts of scientists to re-create the conditions under which they think life arose, whether it is in forming a strand of RNA or figuring out how to form a lipid membrane of the sort that surrounds every cell. Some scientists believe that the constituents of life have to come together fast, within 10,000 hours, because of the entropic forces that would destroy the constituents. That leads some to believe that they will achieve this in the next ten years.

In the end, he comes back to the question of the definition of life, cataloging the many scientists have proposed. He introduces us to Carol Cleland, a philosopher of science who thinks the whole enterprise is flawed and that what is needed is not a definition of life but a theory of life that helps us understand what life is.

As one reads Zimmer’s account, one realizes what is so fascinating in this quest to understand life and how it is possible. Zimmer introduces us to so many forms of life and the wonder of a planet teaming with life from microbes to every other form of life including ourselves. Some religious believers dismiss this whole quest to understand life and its origins with a wave of the hand saying, “God did it.” I’m not so quick to dismiss these quests. I realize some see nothing beyond the physical reality. Others, and I include myself here, would recognize in every scientific discovery the wonders and wisdom of God. If someone replicates the physical processes by which life arose, I will be delighted rather than distraught. My faith doesn’t rest on the gaps in our knowledge remaining gaps.

Zimmer gives us a glimpse at the reality of science. He shows us both the amazing things we are learning about the world, and the questions that remain, some on which multiple generations of scientists will work. He shows us the mistakes, and the ways that continued research and the rigorous peer review processes of science correct those mistakes. He shows us the big questions and what we still don’t know. This is great science writing!


Disclosure of Material Connection: I received a complimentary review copy of this book from the publisher via Edelweiss. The opinions I have expressed are my own.

One thought on “Review: Life’s Edge

  1. Pingback: The Month In Reviews: February 2021 | Bob on Books

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