Book Review: Life's Edge

by Janie
 

Life's Edge

The Search for What It Means to Be Alive

By Carl Zimmer

 

Ask biologists what they study and the answers will quick­ly home in on living things, on parti­cular life­forms that they've spent count­less hours think­ing, scru­tiniz­ing, ana­lyz­ing, and toil­ing over. Yet one further ques­tion – what exactly is a living thing? – is a sure-fire ticket to hesi­ta­tion.
 

Figure 1. American book cover. Source. Fron­­­tis­piece.

It's a good ques­tion, and it's tackled by science writer Carl Zimmer in Life's Edge: The Search for What It Means to Be Alive. The book compels readers to con­tem­plate how pos­sibly to define what makes some­thing alive by meld­ing scien­tific snip­pets on di­verse life­forms, his­tori­cal tales, per­sonal anec­dotes, and a bit of philo­sophy. From the begin­ning we are intro­duced to a mena­gerie that perches in the gray area bet­ween alive and not-alive: creatures like tardi­grades and nema­todes that can re­emerge from crypto­biosis with the touch of water, pythons whose basal meta­bolic rates can grind almost to a halt, slime molds that display a brain­less kind of mem­ory and problem-solving abil­ity, and a girl named Jahi McMath, who was dec­lared brain-dead yet had a beat­ing heart and con­tinued to grow before dy­ing (again) five years later. SARS-CoV-2 makes an ap­pear­ance, since a book on the def­ini­tion of liv­ing would not be com­plete with­out a look at viruses. We are intro­duced to var­ious def­ini­tions of life, sourced from sci­entists to phil­osoph­ers, and we find that these tele­scope down to five special hall­marks: meta­bolism, infor­ma­tion gath­er­ing, homeo­stasis, re­pro­duc­tion, and evol­ution. It's through biz­arre and won­drous flora and fauna that the sheer diver­sity with­in these traits is shown, and the elu­sive­ly com­plex nature of defin­ing life made pal­pable. As quoted in Life's Edge, biol­ogy is indeed a "sci­ence in which the most impor­tant object has no defin­ition."
 

Bizarre creatures have long been invol­ved in defin­ing the fron­tiers of life, as we see with the book's turn towards the his­tor­ical. In the 1700s, Swiss nat­uralist Abraham Trembley dis­covered the regen­era­tive ability of Hydra as he sliced and diced and regrew whole organ­isms from those little "polyp" pieces. We are intro­duced to the mech­anical vis­ion of life propel­led by Descartes' writings, and to the vitalist move­ment, which op­posed the for­mer and believed that all liv­ing things pos­sess a special life force. We learn of red her­rings, like the 1800s dis­covery of a "living jelly" from the ocean, Bathybius, which turned out to be gyp­sum reac­ting with alco­hol to form a gelat­inous prod­uct, and the 1900s dis­covery of "micro­scopic crea­tures" dub­bed radiobes, which turned out to be com­pounds formed when radium encoun­ters bouillon. We meet a multi­discip­linary cast of sci­entist prota­gonists who have tried to bottle up a def­ini­tion of life, from a physio­logist moon­lighting as a spy, to phy­sicists like Bohr, Delbrück, and Schrödinger tack­ling biol­ogy through the phy­sicist's lens, and all the while, the NASA defin­ition of life – "life is a self-sustained chem­ical sys­tem cap­able of under­going Dar­winian evol­ution" – grows increas­ingly flimsy.
 

I esp­ecially enjoyed the high­lighted con­nec­tion bet­ween biol­ogy and crea­tive writing. We are intro­duced to the grand­father of Charles Darwin, Erasmus Darwin, whose poetry propel­led the idea of evol­ution into the public eye (ideas later to be ex­pounded upon by his grand­son). The poet's prop­osal that simple life-forms arose from or­ganic mat­ter inspired a bevy of writers, includ­ing none other than Mary Wollstonecraft Shelley. From this inter­est in life­forms and the 1800s notion that elec­tricity was inti­mately linked to life arose the novel Frankenstein, in which the titu­lar sci­entist brings his mon­ster to life using elec­tricity. This snip­pet was a fascin­ating illus­tra­tion of the synergy bet­ween sci­ence com­muni­cation, sci­ence fic­tion, and sci­entific research, at work since one of the earliest sci­ence fic­tion novels.
 

Frankenstein's fic­tional tech­niques were a har­binger of the spark essen­tial to the 1952 Miller-Urey exper­iment, that land­mark in origins-of-life res­earch immor­talized in liter­ature and text­books. Life's Edge con­tains a con­densed sur­vey of histor­ical origins-of-life res­earch, and here it tran­sitions from a nar­rative of scien­tific snip­pets and his­tory into one com­posed more of per­sonal vig­nettes. Unlike Michael Marshall's The Genesis Quest (a com­prehen­sive read on Origins res­earch that we prev­iously cov­ered on the blog), Life's Edge con­tains a more per­sonal take with anec­dotes and Zimmer's encoun­ters with scien­tists. Feat­ured prom­inently is David Deamer, a major prop­onent of the hypo­thesis that the ori­gins of life lie in lipo­somes and vol­canic hot spring pools, and a multi­discip­linary bunch of sci­entists whose collab­orative work rev­olves around proto­cells, simple lipid-membrane ves­icles remin­iscent of prim­itive cells.
 

I enjoyed the book. It was a thought-provoking pop-sci read that brought the lab environ­ment alive and painted a switch­back path of inquiry, mis­takes, and dis­coveries. Zimmer's wri­ting is enjoy­able and acces­sible: at times sus­pense­ful, at times lyrical, always car­rying an under­current of wonder­ment with the nat­ural world.
 

The book evokes a pal­pable excite­ment in learning about the div­erse attempts at defin­ing life. It rem­inded me of the enjoy­ment found in reading old lib­rary books marked up by prev­ious readers: in the under­lining of cer­tain sen­tences, or in the brief thoughts scrib­bled along page margins, the next reader can observe a com­munal effort to find mean­ing. To some, it's off-putting van­dal­ism; to others, it's a peek into other people's minds and his­tory. The value in these mark-ups – and in the quest to delin­eate what is alive – may not be in which exact words are high­lighted or circled, but rather in the pro­cess of dis­covery.
 

I hap­pened to read Life's Edge around the same time I read The Book of Disquiet by the Portuguese writer Fernando Pessoa. The two books syner­gized. They both read to me as appre­cia­tions of the uncer­tainty of all things and the creat­ivity that arises as a result. In the words of the prota­gonist in the lat­ter book, "the oracles who said 'Know thyself' prop­osed a task greater than all of Hercules' labours and an enigma even more obs­cure than that of the Sphinx.'" Undoubt­edly an apt des­crip­tion.
 

The answer to what is life? has under­gone a kind of evol­ution itself, and Life's Edge is an adept tour guide to that convol­uted path.