In 1944, the Nobel Prize-winning physicist Erwin Schrödinger published a groundbreaking little book called What Is Life? In fewer than one hundred pages, he argued that life was not a mysterious or inexplicable phenomenon, as many people believed, but a scientific process like any other, ultimately explainable by the laws of physics and chemistry.
Today, more than sixty years later, members of a new generation of scientists are attempting to create life from the ground up. Science has moved forward in leaps and bounds since Schrödinger's time, but our understanding of what does and does not constitute life has only grown more complex. An era that has already seen computer chip-implanted human brains, genetically engineered organisms, genetically modified foods, cloned mammals, and brain-dead humans kept "alive" by machines is one that demands fresh thinking about the concept of life.
While a segment of our national debate remains stubbornly mired in moral quandaries over abortion, euthanasia, and other "right to life" issues, the science writer Ed Regis demonstrates how science can and does provide us with a detailed understanding of the nature of life. Written in a lively and accessible style, and synthesizing a wide range of contemporary research, What Is Life? is a brief and illuminating contribution to an age-old debate.
Ed Regis holds a Ph.D. in philosophy from New York University and taught for many years at Howard University. He is now a full-time science writer, contributing to Scientific American, Harper's Magazine, Wired, Discover, and The New York Times, among other periodicals.
What Is Life? Investigating the Nature of Life in the Age of Synthetic Biology By Ed Regis (2008) with a July 2026 update!
Ed Regis's What Is Life? follows scientific groups in Europe, America, and Japan racing to build an artificial, or synthetic, cell, and uses that race as a way into a much older and thornier question: what does it actually mean for something to be alive, and can that meaning be pinned down precisely enough to build in a laboratory. Regis wisely refuses to answer the question outright in his opening pages. Instead he offers a minimal, working definition to get the reader started: something alive has to take in nutrients and convert them into energy through metabolism, it has to reproduce itself, and its descendants have to be capable of evolving. He is upfront that this hardly settles the matter. It is simply a place to stand while the more difficult argument unfolds.
The heart of the book, and its most valuable contribution for the general reader, is Regis's treatment of Erwin Schrödinger's 1943 lectures and the short book that grew out of them, also titled What Is Life? Schrödinger, a physicist rather than a biologist, and a Nobel laureate in physics from 1933, set out to explain how something as small as a gene could possibly carry all the information needed to construct a living organism, given that at that scale everything is subject to the random jostling of heat motion, or Brownian motion, that ought to scramble any such delicate arrangement. Schrödinger's answer was that living matter evades the decay implied by the second law of thermodynamics by continuously drawing what he called negative entropy from its surroundings, which in practice means food and oxygen. He guessed, incorrectly as it turned out, that a gene was a large protein molecule with its instructions written in code. Genes are in fact nucleic acids, not proteins, but Regis is careful to explain that Schrödinger's larger achievement was not the guess itself. It was his demonstration that biology need not be treated as a separate and lesser science, that life could in principle be explained using the same physics and chemistry that governs everything else in nature. Watson, Crick, and Wilkins, the scientists who later worked out the structure of DNA and shared the Nobel Prize for it, each said that Schrödinger's book had shaped their own thinking.
I found Regis's explanation of Schrödinger's argument considerably clearer than Schrödinger's own writing on the subject. Schrödinger's original lectures were addressed to an audience that already had some grounding in physics, and the prose, tends to move quickly through concepts like entropy, quantum indeterminacy, and molecular stability that a general reader has no particular reason to already understand. Regis slows down. He builds the argument in the order a non-specialist actually needs it: first the puzzle, of how something so small and so exposed to random thermal motion could reliably store and transmit hereditary information across generations, then Schrödinger's proposed solution, then what turned out to be right about it and what turned out to be wrong. That sequencing, along with Regis's willingness to restate the stakes plainly rather than assume the reader already grasps why the puzzle matters, is what makes the chapter work. A reader who came to this book with no background in physics or genetics will leave Regis's account with a genuine, working understanding of why Schrödinger's lectures mattered, something Schrödinger's original text does not make nearly as accessible.
From there Regis traces the path forward to Watson and Crick's 1953 discovery of the double helix, including the detail that each bond in the structure sits at a 36 degree angle that produces a full turn every ten repeats. He makes the point, easy to overlook, that the original Watson and Crick paper never once uses the words amino acid, protein, or genetic code, because the mechanism of the code itself was still completely unknown at the time. Regis also gives useful, brief attention to the four nitrogen-based building blocks of DNA, adenine, thymine, guanine, and cytosine, to the differences between DNA and RNA, and to why E. coli became such a popular laboratory organism, since as a prokaryote its genetic material floats freely in the cytoplasm rather than being sealed inside a nucleus.
A particularly enjoyable section of the book covers a 1993 Dublin conference convened to mark the fiftieth anniversary of Schrödinger's original lectures, and Regis does not shy away from how contentious it was. Several major figures, including Linus Pauling, Max Perutz, and Stephen Jay Gould, were openly dismissive of Schrödinger's lasting contribution, while others at the conference offered their own competing definitions of life. Manfred Eigen proposed self-reproduction, mutation, and metabolism as the three defining traits. Stuart Kauffman pushed back against the near-universal assumption that self-replicating molecules like DNA are essential to life at all, arguing instead that life might be an emergent property of many molecules and catalysts interacting together. Freeman Dyson argued that reproduction alone was too narrow a test, since sterile organisms such as mules, and individual organs within a living body, are plainly alive without being able to reproduce, and proposed that metabolism might be the more fundamental marker. Regis lets these disagreements sit rather than resolving them, which is honest, since scientists themselves have never resolved them.
The book's discussion of metabolism and ATP is similarly well handled. Regis describes metabolism as the process by which an organism takes in raw materials and converts them into what it needs to sustain and grow itself, with a nod to Hans Krebs, whose 1937 work mapped out the metabolic steps involved. Adenosine triphosphate, or ATP, is presented as possibly the true spark of life, recycled into adenosine diphosphate and back again 2000 to 3000 times a day inside the mitochondria, organelles so small that a billion of them together would scarcely fill the space of a grain of sand.
Regis is candid, too, about how little is actually settled regarding the origin of life itself. He notes, with something like dry amusement, that Francis Crick, himself a Nobel laureate, leaned toward the speculative idea that life arrived on Earth from elsewhere in the universe, a form of panspermia that critics have less charitably called the flying saucer theory of life's origin. Another scientist at the same discussion put it more bluntly, essentially admitting that nobody has “a freakin’ clue” as to how life began. Regis's willingness to let that uncertainty stand, rather than papering over it with false confidence, is one of the book's more honest moments.
Later chapters build toward the book's central practical question. Regis discusses Freeman Dyson's two-part definition of life as the combination of metabolism and replication, and points to the 2002 synthesis by Jeronimo Cello, Aniko Paul, and Eckard Wimmer of a complete poliovirus genome, assembled entirely outside a living cell, as proof that life's informational substrate can in principle be manufactured rather than merely copied. Rather than continuing to chase a single, all-purpose definition of life, which the Dublin conference suggests may not exist, Regis discusses an alternative worth taking seriously: a synthetic cell Turing test, in which a manufactured chemical system would only need to behave enough like a living thing, through self-repair, growth, and evolution, to convince an observer it was alive. The book closes by testing the boundaries of life from the other direction, through death, using brain death, persistent vegetative states, and so-called beating-heart cadavers to show how metabolism and consciousness can become decoupled from one another. It is a genuinely unsettling way to end, and an effective one.
What Is Life? is at its best not when it is trying to settle the question in its title, since Regis is honest enough to admit that no one has settled it, but when it is explaining, patiently and in plain language, how the smartest people of the last century have tried and failed to settle it. His treatment of Schrödinger alone, clearer to the general reader than Schrödinger's own writing, justifies the book. Readers with an interest in synthetic biology, the history of molecular genetics, or simply the philosophical puzzle of what separates the living from the nonliving will find this a rewarding and accessible guide.
Postscript: SpudCell, July 2026
As if on cue, this review can close with a real-world coda to the questions Regis leaves open. On July 1, 2026, Kate Adamala and Aaron Engelhart's team at the University of Minnesota announced SpudCell, the first synthetic cell with a complete life cycle built entirely from non-living chemical components. The name, Adamala has said, is a nod to Sputnik, with a wink toward her own heritage. Housed in liposomes, simple droplets bounded by fatty acids, and drawing on the decades-old PURE system of basic biomolecules, SpudCell feeds, grows by fusing with other droplets, replicates its roughly 90,000 base pair genome, and divides, for about five generations before the system runs down. That genome is smaller than what biologists had long assumed was the practical floor for a living cell, and it lacks a cytoskeleton and cannot yet make its own ribosomes, borrowing them instead from E. coli during feeding. The research has been posted publicly ahead of peer review, and Adamala and her colleagues have founded a public-benefit institution, Biotic, to share the underlying method openly with other laboratories.
SpudCell lands squarely inside the arguments this book stages. It is, in effect, a working attempt at the synthetic cell Turing test Regis proposes as an alternative to ever settling on a single definition of life: a manufactured chemical system that feeds, grows, and reproduces convincingly enough that observers are calling it, at minimum, life-like, and in some press accounts, alive outright. Its small genome speaks directly to the Dublin conference debate the book recounts over what is truly essential to a living system, and the demonstrated competition among genetic variants across generations touches on Manfred Eigen's three-part definition of life as self-reproduction, mutation, and metabolism. Schrödinger, writing in 1943 about how something as small as a gene could carry the instructions for life, could hardly have imagined that same question would one day be tested by building the gene-carrying system from scratch, in a lab, out of non-living parts. Regis's book, though published in 2008, gives a reader everything needed to understand exactly why SpudCell matters.
"Despite the enormous fund of information that [biologists] have provided," wrote Carl Sagan in 1970, "it is a remarkable fact that...there is no generally accepted definition of life." This book provides a gripping, (very) brief tour of the present "enormous fund of information" we now have on living functions:
1) Replication (the discovery of DNA in 1954; the breaking of the nucleotide/amino-acid Genetic Code in the 1960s--on through the Recombinant DNA revolution of the 1970s through "synthetic" viruses composed from genetic scratch in the 1980s), 2) Metabolism (the Krebs cycle; the universal role of ATP), 3) Evolution (the Modern Synthesis uniting genetics and natural selection)
Regis also describes attempts in this century to devise novel lifelike systems in the form of artificial "protocells" and chemical "chells"
Despite this veritable avalanche of information of how living systems work, it remains a baffling fact that the simple question, "What is life?" remains as disputed as ever. One begins to wonder whether this question might be an empty philosopher's quixotic quest. In this spirit, there might be something to be said for Edouard Machery's dilemma-diagnosis in his essay (discussed by Regis), "Why I Stopped Worrying About the Definition of Life...and Why You Should as Well" (2006): "the project of defining life is either impossible or pointless," he writes, since either 'life' refers to "a traditional and ill-defined 'folk notion'" or else the definition of 'life' is to be fixed by "a precise, scientific theoretical concept." If the former, then defining 'life' slides into Socratic silliness; but, if the latter, then *every* scientific sub-discipline will have its own 'fixed' definition...and there's nothing to be said beyond that (pp. 158-159).
I can't help but think that anyone who gives Regis's primer a read will soon be inspired to follow up by exploring many of the scientific vistas Regis points out.
This book explores some fairly arcane subjects, including the efforts of scientists to create or manufacture an artificial cell that would perform basic biologic functions, putting genes from one species into another, making genes in the laboratory from published genome sequences, and artificial genes. Central to the book is the question of what life is, and how scientists and philosophers have struggled to answer what at first blush seems to be such a simple question, but which has so far eluded a generally accepted answer. Is life something that emerged from an arrangement of molecules? If so, did those molecules self-assemble, or does something else cause life to arise? The book is small and written in easy to understand terms. But it still made my head hurt.
Revisiting both Schrödinger's eponymous collection of lectures, as well as the current state of the art of scientists asking that eponymous question, Regis's book is a whistle-stop tour of all the interesting ways in which the mysterious process of Life on Earth is being interrogated to yield new understanding, and possibly new technologies. Scientists are working on constructing a living system from chemical raw ingredients, some think that a sufficiently self-organized system could be considered "alive", no matter what it's made of, and some want to build new forms of life by using the biological ingredients we have at hand to create a Franken-being that will do its master's bidding. Throughout, we meet with several processes which, taken together, seem to constitute the minimum criteria for life. Life is not just one easily quantifiable characteristic. Life is complicated.
Parto con la premessa che questo libro mi è stato dato da leggere e generalmente i libri che mi vengono assegnati da qualcun altro non mi fanno impazzire. Nonostante ciò questo libro ha saputo intrattenermi, anche se di biologia io sapessi quasi nulla. Il libro è scritto molto bene ed è perfettamente comprensibile da chi, come me appunto, non sa nulla sull'argomento. Ogni capitolo aggiunge informazioni inerenti qualsiasi argomento che riguardi la vita(evoluzione, metabolismo, perfino l'origine della vita sulla terra), approfondendo la storia di come si è arrivati a quella conclusione, il tutto con un lessico molto semplice. Non lo considero un capolavoro ma se siete in cerca di un libro che vi spieghi in generale cosa contraddistingue i viventi dai non e come siamo nati su questo pianeta questo libro vi piacerà.
Love the concept! Has many interesting ideas that are explained thoroughly and it flows like a normal book. There are a couple of pictures here and there as well as some humor that adds a nice touch. Ed Regis is a very talented writer. Of course, as it is a nonfictional science book, it was a little bit of a slow read because it’s not really my preferred style of reading, but it was good nonetheless!
Attention captivating, reading this book made my brain feel bigger. Just like schrodinger never answered the question in his version of what is life, neither does Ed Regis. However this book takes you through the life of that question and gives you the many different answers that have been scientifically thought of, while at the same time showing just how hard it is to define the term life
Regis begins this book by describing current efforts to create a cell. This leads to a multi-chapter discussion of, "What is life?" Surprisingly, the answer is not so clear, although in the end Regis narrows the range of answers down to metabolism: Life draws energy from the outside to "make something: new structures, new proteins, energy. Metabolism means synthesis...." In other words, life builds self-sustaining structures and systems.
In thinking about this definition, a few things seem to be missing. How did life make the transition from non-life? Was it a soup of chemicals that randomly came together in the right way so that self-sustaining life emerged? If there's random creation, does life have an overarching end, such as survival and reproduction ("moving genes into the next generation, per Dawkins)? If so, how did such ends emerge from randomness? Or, alternatively, as all non-life matter and energy, is life free movement in a different form? If so, might that form involve flexibility ("self" adjustment of structure and action to fit the environment) in how that freedom of movement is to be obtained? And, at the juncture between non-life and life, is this the very beginning of free will and choice about how life's (fixed) end is to be achieved?
Regis does not dig into these questions, but his book does prompt such thinking. He is an excellent writer. This is an excellent book.
Not a bad read, though not what I had expected. Perhaps I was looking for something more definitive, something that would come closer to answering the big question. Synthetic biology doesn't play as a large a part in the text as I thought it would from the title.
Instead, it's a summary of how different scientists have approached the beginning of life and have attempted to define life. The writing is very easy to follow and is done in such a way that people with no biology or chemistry background should have no trouble following the ideas presented.
Not the most original book, but then again you might have guessed that from a book that repeats the title of a classic 60 year old book and has chapters that repeat the titles of some classic papers (e.g., The Spandrels of Saint Marco).
But it is a thoughtful, excellent, enjoyable, if occasionally journalist, overview of the title question. And most important it is completely up-to-date, having been published this year (2008) and including substantial reflections motivated by recent progress in synthetic biology.
At 173 pages it is worth reading it yourself. And if you don
A rather short book, that doesn't go into much more than a few pages of detail for any one topic. Annoyingly, synthetic biology isn't even mentioned before the last 30 or so pages of the book.
Worth the (quick) read for a cursory review of the history of big milestones in evolutionary biology, but that's all.
OK introduction to the theories of life's beginning and somewhat more thorough review of work being done to re-create life in the lab. Also discusses, as the title suggests, different views on the definition of life. The best answer? Though I hate to be a spoiler ..... "metabolism"!
An abbreviated but thorough look into the emergence of synthetic biology and genetic engineering as well as some foresight into the search for abiogenesis. If you love the histories and mysteries of biology as much as I do, this book is for you.
Great book, attempted to answer a difficult question and did a pretty good job. Contains some interesting biochemistry history and provides some interesting ideas about what the future might hold. Definitely worth the read.
More of an essay than anything else, but a good way to stimulate thought nonetheless (Also, I liked the book's physical attributes - the size, the weight of the pages, the cover...)