This is a really interesting and philosophical book. Like another reader, I had a very hard time getting through it and sticking with it. The chapters are very short and involve a lot of storytelling, which usually helps me finish books quickly. It’s a fascinating topic and he writes well. I’m not sure why it was a miss for me but I’m sure it was a case of it’s not him, it’s me. Still highly recommended.

I read a digital copy of this book for review.

The Intriguing Question: What is Life?

I think most of us believe we know what life is until we think about it hard. After all, we’re alive, but so are many things that don’t share the characteristics of ourselves or even other vertebrates. A fascinating question in this time of Covid19 is whether viruses are alive. Many researchers don’t think so. Then there are slime molds that can move toward food and tardigrades who apparently die from losing all their water, but come back to life when water is restored. This is only a sampling of the many life forms discussed in this book.

The book is basically the story of the author’s odyssey searching for various life forms to see if the question has an answer. From looking at living animals to discussions with scientists who are trying to create life, this is a fascinating journey. The book started slowly for me with stories of life forms that are familiar. However, the further he progressed on his journey, the more unusual the life forms were. I found it hard to put down.

The book is well written and easy to understand even if you aren’t normally into science. I was particularly interested in the techniques that relate to medicine which include using skin cells to grow neurons to study diseases. This book is well worth reading if you’re interested in what life is even if there are no solid answers. I highly recommend it.

I received this book from Dutton for this review.

Carl Zimmer took quite the challenging subject here, which is basically, What is life? There were a lot of subsets of questions that were also looked at within that subject. What is consciousness, what makes us human, how did life start from non-living structures?
What I appreciate about this book is that it doesn't shy away from controversial subjects. For example, the subject of abortion, a hot button topic at any point. Why would this come up in a book about life? Zimmer does a great explanation of the topic, bringing in the history, science, and religious aspects of the controversy. What you can walk away from his presentation there are no easy answers but it is complicated. There are no easy solutions to this subject. We fight about this sort of thing because we can't have a clear definition of what something is.
There are no simple answers in science. That maybe we need to relearn how to look at the world, that we cannot just categorize into nice neat boxes. Carl Zimmer has delivered a great readable book that is more honest about how science works than many others I have recently read, and more people would be better off having this kind of understanding.

"…the question of what it means to be alive has flowed through four centuries of scientific history like an underground river… More than 150 years later, despite all that biologists have learned about living things, they still cannot agree on the definition of life. "

I have had the pleasure of driving up a mountain through mist and cloud, and of walking in London through pea soup fog. Where exactly did the clear air end and the more particulate air begin? It is not entirely…um…clear. Sure, there is a difference between standing, or driving in air that one cannot visually penetrate and looking through a wide outdoor expanse on a cloud-free, crystalline winter day. But it is not a barrier drawn with a straight edge. Thus it appears with the line between living and not-living. With the examples detailed in Life’s Edge, it is clearer than ever that there are more things under heaven and earth than had been dreamed of in our philosophies. There are those, certainly, who proclaim that this or that specific location is where the thing called life begins. Rules have been drawn up to plant markers, to draw lines. But like an outdoor crime-scene police-tape, the fog of what lies within and without wanders freely past those lines, with no regard for the designs or preferences of humans.

New York Times science columnist and multiple-award-winning science-writer Carl Zimmer’s fourteenth book takes readers on an exploration to that amorphous borderland between the living and the non-living. It is a journey that raises a lot more questions than it answers. Zimmer employs a tried and true approach, each chapter moving on to the next lab, the next researcher, the next wild bit of research, and filling in with nice chunks of science history, as he circles around the question.

Many of the things Zimmer reports on are fascinating. Some, however, will disturb your sleep. For an example of the latter, Alysson Muotri, at the Sanford Consortium for Regenerative Medicine, takes skin samples and reprograms them into neurons to study neurological diseases and possible treatments. They are grown into miniature organs called organoids, and are allowed to reproduce, up to a point. When he started growing these things, he assumed that they could never become conscious. “Now I’m not so sure, he confessed.” Zimmer tells, also, of a researcher, a very long time ago, who was notorious for experimenting on living animals.

Clearly a significant concern for our culture is where “life” begins, and further, where “human life” begins. It all comes down to definitions. Is Thomas Aquinas’s notion of the “ensoulment” of human embryos the same as defining when life becomes human life? There have been other notions employed in the history of Christianity. Zimmer looks at how legal definitions of life, for purposes including supporting abortion laws, and concerning a widening spectrum of medical and legal issues, fail to hold up under scientific scrutiny.

The concern here is not just what is life, but how can we tell when something actually is alive? He looks at how humans perceive life and react to it. We have a sense of life being present or absent, an intuition that is not unique to our species. Ravens hold what can only be seen as funerals for dead flock members. Chimps engage in group laments for late members, as do many other creatures.

"To be alive is to not be dead…Humanity did not come to this realization through logic and deduction. Our understanding of death is not like Darwin’s theory of evolution or Thompson’s discovery of the electron. It has its origins in ancient intuitions. "

Zimmer looks at metabolic rate. In the 17th century, there was a widespread fear of being afflicted with a death-like state that might leave its victims without detectable breath or heartbeat, thus generating a rampant terror of being buried alive. This concern inspired a well-known short story.

"The boundaries which divide Life from Death are at best shadowy and vague. - Edgar Allan Poe, The Premature Burial"

Zimmer reports on a woman who was pronounced dead, twice. Where is the line between brain death and true, no backsies, total death? Can a person meet the criteria for brain death one day, and later not meet it?

But what constitutes life? How about adding some ingredients to agar, leaving it alone for a few hours and then finding a thriving slime mold, one with remarkable survival skills. What about spores, some of which can survive in space? Are spores alive? Or only potentially alive, or an ingredient in a recipe for making life?

"Scientists have been arguing over whether viruses are alive for about a century, ever since the pathogens came to light. Writing last month in the journal Frontiers in Microbiology, two microbiologists at University College Cork named Hugh Harris and Colin Hill took stock of the debate. They could see no end to it. 'The scientific community will never fully agree on the living nature of viruses,' they declared. - from Zimmer’s Secret Life piece in the NY Times"

Whether you prefer your undead to be of the vampiric, zombie, or reanimated sort, or are more inclined to unicellular spore candidates, or maybe pre-conscious organoids, there are plenty of candidates for entities on the fringes of life.

In addition to providing readers with a better handle on the attempt to delineate the line between life and not-life, there are plenty of interesting questions raised and fun facts to be gleaned. We learn, for example, that Erwin Schrödinger was set up by the governmental at Trinity College. (But he may have simultaneously both been there and not, depending on whether any students saw him give a lecture.) We also learn that when Vitamin C was discovered, the discoverer wanted to name it “Godnose.” And how about meteorites as a possible source of Terran life? Or maybe they contributed one or more of the ingredients necessary for the recipe? I particularly enjoy when science writers imbue their work with a sense of humor. That is mostly lacking here, which is disappointing. But there is plenty of material to keep your brain cells flashing on and off.

Who decides on a definition of life? In an ideal world, science should lead on matters that are subject to physical investigation and repeatable experimentation. And yet…

It may be enough for you to align with Supreme Court Justice Potter Stewart who, when it came time to issue a ruling pertaining to pornography, said that he knows it when he sees it. We as a species tend to think that we know life when we see it. But it would be a good thing to recognize that all extant definitions of life are squishy, relying on philosophy or religion for their support. So I would appreciate it if no one would use their definition to tell me or anyone who does not share their perspective what they can or cannot do. Because when it comes to folks twisting science to political ends, I know it when I see it.

Life’s Edge may not provide a definitive guide to the line between living and nonliving. Such a line does not really exist in biology. But it does point out where the arguments lie about where those lines might be drawn, or, at least, where they might be investigated. It raises the larger question, though, of whether that line can, at least from a scientific perspective, be drawn at all.

"Life is what the scientific establishment (probably after some healthy disagreement) will accept as life."


Review posted – March 19, 2021

Publication date – March 9, 2021

I received an e-book ARE if Life’s Edge from Dutton through NetGalley in exchange for an honest review, and some of those interesting things that have been growing, unasked, in my basement. Thanks, all.

For the full review, with images and links ,please see my review on Goodreads - https://www.goodreads.com/review/show/3854903242

In the past year alone, humans have landed multiple devices on Mars, retrieved samples from the Moon and not one but two asteroids, delved ever deeper into the Earth, and shattered records for the recovery of DNA from ever-older specimens. Meanwhile, plans are being hatched to zip a helicopter around Titan to examine its pools of liquid hydrocarbons, fly a probe through the geysers of Enceladus to collect samples, scoop surface ice off Europa, and use the next generation of space telescope to examine the atmospheres of exoplanets light-years away. All in the search for life.

Given all that time, effort, and money, one could be forgiven for assuming that we know what we’re looking for. But, as Carl Zimmer makes explicitly clear in his newest popular science work, Life’s Edge: Searching for What It Means to be Alive 2(021), that’s not even close to reality. Turns out we not only don’t know the meaning of life (OK, 42); we don’t even know what it means to be alive.

To try and circle around the question, if not arrive at an actual answer, Zimmer has penned a series of linked essays that explore various aspects of the mystery and the many attempts, historical and contemporary, to solve it through various means: chemistry, biology, physics, philosophy, astronomy. He travels to a mine in the Adirondack Mountains of NY to count hibernating bats, to laboratories to watch slime molds find the shortest path to food, to a New England Arboretum to learn how maples reproduce, to the Jet Propulsion Lab to interview astrobiologists about NASA’s search for life. He explores the long-running medical problem of when to declare someone dead — is it when the heart stops? The lungs? Brain activity? — as well as the just as long debate between vitalists, who believed in a “vital force that endowed matter with self-directed motion [and] purpose, and Cartesians and their “machine-centered view of life … seeing themselves in league with clock repairman.” And finally he ends just where one might expect in a book that begins with questions of how life began — in several labs trying to create life anew.

Along the way we get some familiar definitional parameters: life has to reproduce, life has to metabolize (eat and turn that food into energy), life has to evolve, and others. And just as quickly as Zimmer offers up these requirements, he shows us the exceptions or at least the boundary-blurrers, such as computer programs that evolve in self-directed manner and tardigrades that enter a weird no-person’s land between life and death (here you might ponder the thought that tardigrades might even now be living on the Moon thanks to a crashed probe).

It’s all endlessly fascinating, not in spite of life’s ambiguities and contradictions, but because of them. Zimmer doesn’t appear to have any leanings one way or the other on the various theories, at least not one that shows, but what shines throughout is his curiosity and his desire to explore all nooks and crannies, including not just scientists but also writers and philosophers. Nor does he highlight only the “successes”, since science advances as much via what some might call its “failures” (or at least errors), which Zimmer treats with the same respect as he does those theories that have better withstood the test of time. Meanwhile, his prose is always clear and smooth, and his explanations never get bogged down in too much detail or complexity. Sometimes a few of the sections feel like they end a bit abruptly, or the linkages could be a little smoother, but these were niggling issues in an otherwise informative and fascinating work. In the end, you won’t have an answer to, “What is Life,” but you’ll be exhilarated at the journey to find out.

“The boundaries which divide Life from Death are at best shadowy and vague.” Poe wrote. “Who shall say where the one ends, and where the other begins?”

In his latest book, popular science writer Carl Zimmer undertakes the monumental task of looking at how the quality of being alive is defined. This is trickier than it may first appear.

He tells stories both from scientists working now on various undertakings that touch on what it means for something to live — from snakes to bacteria and all manner of life in between — and looks at people and moments from biology’s history. Although he does tell parts of well-known stories, like Watson, Crick, and Rosalind Franklin (who deserves more credit than she’s usually given), there were so many stories here of people who were wrong, mistaken or off track in some way, and others whose contributions, like White’s, have been largely lost to history.

Querying biologists, Zimmer says we can pick out a set of hallmarks that reappear: metabolism, information gathering, homeostasis, reproduction, and evolution. Beyond that, it gets complicated quick.

This book had one of the best arguments for pro-choice as a matter of inarguable logic I’ve ever read. He even shows how the definition of life varies across cultures, citing a rural Ivory Coast village where babies aren’t considered as “truly belong[ing] to this world” until they lose the stump of the umbilical cord. If it dies before that falls off, “there is no death to observe.”

Here’s my favorite bit of that, and an example of why Zimmer is such an exceptional writer, as he describes how the fusion of egg and sperm isn’t at all a straightforward beginning of life:

The flow of life arrives unbroken from the previous generation, and from generations back through the ages. You’d have to canoe up life’s river for billions of years before reaching its headwaters.

“Life begins at conception” is a simple slogan, easy to remember, easy to shout. Taken literally, though, it’s false on its face.

He also has a sense of humor that makes this eminently readable and at times really delightful. Zimmer’s storytelling in general is wonderful — easy to see why he’s such a popular and accessible writer in this field. This is actually one of those books I’d gladly read again, as despite being approachable for the layperson, it’s almost deceptively information-packed and I know I didn’t get everything on a first pass.

Plus sometimes I was just distracted by how much I liked traveling with him, as it were, and reading his often-lyrical writing. A chapter addressing viruses, those notoriously not-dead-but-not-really-alive things, includes this vivid imagery: “It’s strange that people can push viruses out of the house of life and leave them hanging around the doorstep.”

There was so much more to these ideas than I’d naively imagined. Zimmer is the ideal companion explore such a complex topic with, as he breaks concepts down understandably, compellingly, even kind of thrillingly.