What Is Life? Dropped Into a Tumultuous Time for Science As Well As for Sociopolitics

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lectures’ anniversary with a conference called Schrödinger at 75 — The Future of Biology.) Since the 1930s, biology had been turning from a largely descriptive science into one

concerned with mechanism. Thanks to BETTMANN/GETTY studies such as those by geneticist Thomas Hunt Morgan on fruit flies, researchers were starting to understand heredity in terms of the transmission of genes, envisaged as large molecules arranged on chromosomes. Many expected genes to be proteins. However, even as Schrödinger was preparing his lectures, the microbiologist Oswald Avery was finding evidence that they were nucleic acids. Thus, What Is Life? dropped into a tumultuous time for science as well as for sociopolitics. Schrödinger steps into these cross- disciplinary waters cautiously. He declares himself a “naive physicist”, pondering how life sustains itself and transmits genetic mutations stably across generations. His work on quantum mechanics had earned him a Nobel prize in 1933, but that was hardly qualifica- tion for commenting on biology, in which Schrödinger had previously shown little interest beyond forays into the physiology of vision. Arguably, that naivety is the source of the book’s strengths as well as its weaknesses. The puzzle in the title stemmed from how physicists and chemists then thought of the molecular world, as wholly governed by statistical behaviour. In the classical molecular physics of James Clerk Maxwell and Ludwig Boltzmann, atomic motions are random (see E. Schrödinger Nature 153, Physicist Erwin Schrödinger also probed questions of molecular biology. 704–705; 1944). Precise, robust physical laws, such as those linking the temperature, pressure and volume of a gas, emerge from the average behaviour of countless atoms. IN RETROSPECT How, in that case, can a specific macro scopic outcome — a phenotype, an organism’s observable inherited traits — arise from an individual genetic mutation at the What Is Life? molecular level? Here, perhaps, is a ghost of Schrödinger’s cat, formulated in 1935, Philip Ball revisits Erwin Schrödinger’s influential book, whose macroscopic life or death hinges on a single quantum event. (Mathematician Roger which crystallized key concepts in modern biology. Penrose has said of the thought experiment that “it would not surprise me if Schrödinger had something of this issue partly in mind” n What Is Life? (1944), Austrian physicist What Is Life? The Watson’s discovery in when he wrote What Is Life?.) Looking at an and Nobel laureate Erwin Schrödinger Physical Aspect of 1953 of how DNA’s inherited characteristic (such as the protrud- used that (still-unresolved) question to the Living Cell double helix encodes ing lower jaw common among members of Iframe a more specific but equally provoca- ERWIN SCHRÖDINGER genes. As Crick wrote Europe’s Habsburg dynasty), Schrödinger Cambridge University tive one. What is it about living systems, he Press (1944) to Schrödinger that asks how the allele responsible remained asked, that seems to put them at odds with year, he and Watson “unperturbed by the disordering tendency of the known laws of physics? The answer had “both been influ- the heat motion for centuries?”. he offered looks prescient now: life is dis- enced by your little book”. Here, he cites experiments by another tinguished by a “code-script” that directs Elegant and accessible, What Is Life? grew former quantum physicist, Max Delbrück, cellular organization and heredity, while from a series of enormously popular public whose use of high-energy radiation to apparently enabling organisms to suspend lectures that Schrödinger gave at Trinity Col- induce genetic mutations allowed him to the second law of thermodynamics. lege Dublin in 1943, in the depths of the Sec- estimate a gene’s size at around 1,000 atoms. These ideas inspired the public and a ond World War. Exiled from Austria when it Schrödinger claims that this seems too number of scientific luminaries, but exas- was annexed by Nazi Germany, Schrödinger small for “lawful activity” — durable inher- perated others. Although their elements had been invited to Ireland to help establish itance — to persist in the face of statistical were not original, the formulation bril- the Dublin Institute for Advanced Stud- fluctuations. But he asserts that quantum liantly anticipated Francis Crick and James ies. (This September, Trinity will mark the mechanics can explain the matter. Atoms

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in molecules can typically be arranged in many stable ways, and each configura- tion has an associated energy; this is how Books in brief Schrödinger envisages different gene alleles. But “quantum jumps” between them are Timefulness generally inhibited by high energy barriers. Marcia Bjornerud Princeton University Press (2018) He goes on to propose that such gene- As a geologist, Marcia Bjornerud works in many time frames: the encoding molecules (he was among those 4.5-billion-year history of Earth, the academic year, the daily grind. who suspected that they were large pro- That layered perspective has made her aware of the short-term teins) have enough potential variety in their thinking common in a society wedded to political terms of office configurations to encode huge amounts and the news cycle — all of which has, she argues, contributed to our of information, and that this variety can inadequate, sometimes wrongheaded response to climate change. furnish a cell’s “code-script”. The position In this trenchant study, Bjornerud calls for a new geological literacy of each atom matters, but the pattern does to instil deeper knowledge of planetary rhythms and processes — not repeat — hence his description of the “thinking like a mountain”, as ecologist Aldo Leopold put it. molecules as being “What Is Life? like an aperiodic dropped into (irregular) solid. It Farsighted a tumultuous wasn’t an entirely Steven Johnson Riverhead (2018) new idea; Del- Many researchers (notably psychologist Daniel Kahneman) have time for science wrestled with the subtle mechanics of decision-making. Now, science as well as for brück had sug- gested something writer Steven Johnson has his decisive moment, looking at the deep sociopolitics.” of the kind in 1935. deliberations — mapping of variables, predictions of outcomes and And biologists balancing of aims and possibilities — that underpin life-changing Hermann Muller and J. B. S. Haldane had choices. He draws on research and compelling examples, from George independently proposed that chromosomes Eliot’s 1871 novel Middlemarch (which examines the “threadlike might act as templates for their own replica- pressure” on the deciding mind) to the supercomputer-based climate tion, in the same way that new crystal layers models now influencing climate-relevant decisions across the globe. build up on pre-existing ones. None of this, Schrödinger admits, answers the deeper question of “how the hereditary Birds in the Ancient World substance works” — that is, how it is used Jeremy Mynott Oxford University Press (2018) in development and metabolism, enabling From nightingales trilling in ancient Rome’s suburbs to the migrating an organism to build and sustain itself from cranes minutely observed by Aristotle in his fourth-century-bc moment to moment in what Schrödinger History of Animals, birds pervaded early Mediterranean civilizations. calls its “four-dimensional pattern” in space Jeremy Mynott’s masterful cultural and scientific history tours their and time. But he makes a start on that issue by roles as timepieces, soundscapes, pets, messaging services — even posing the question in thermodynamic terms. intermediaries with the supernatural. The vivid artworks and literary This isn’t a matter of energy (organisms’ passages give this wings: here is the Greek poet Aratus on finches energy intake and output must be balanced, “chirruping shrilly at dawn” before a storm; there, a surreal Roman or they’d burn up), but of entropy, the meas- recipe for flamingo stewed with coriander. ure of atomic disorder. The second law of thermodynamics states that entropy must increase in all processes of change. But Power Button organisms somehow stave off entropic dis- Rachel Plotnick MIT Press (2018) solution. As Schrödinger put it, they feed Push buttons pop up on everything from blenders to aeroplanes. on “negative entropy”, using it to sustain the Yet, as Rachel Plotnick reveals in this unusual technological history, organization apparent in the structures and the mechanism had an explosive impact on culture from its debut in functions of cells, while paying their thermo the 1880s to the 1920s and beyond. The idea that huge machines dynamic dues by heating the environment. or even bombs could be activated by a finger became a metaphor for How they mine negative entropy, he could human hegemony, and a source of fear and wonder. And, as Plotnick not say. He was forced to suggest that, in living notes, some ‘buttonized’ inventions (such as the electrified tie pin) systems, “we must be prepared to find a new may be defunct, but in an era of nuclear weaponry and disruptive type of physical law”. Today, no such drastic leadership, one-touch technology still has the power to shock. solution seems to be needed. The concept missing from his analysis is information. The information theory Bits to Bitcoin of Claude Shannon and the cybernetics Mark Stuart Day MIT Press (2018) of Norbert Wiener in the 1940s and 1950s In this methodical primer, technologist Mark Day examines the began to fill that lacuna, although only more computational infrastructure — the elements that underlie the recently have researchers begun to under- workings of digital devices and networks. He unpicks operating stand how information truly features in systems, examines processes, explains esoteric defensive biology. As Schrödinger’s talk of negative techniques such as cryptography and reveals Bitcoin to be entropy hinted, life is a pocket of out-of- an “intriguing combination of self-interest and mathematics”. equilibrium order in an open system, and the If you want to know why data streams turn lumpy when DNA code is just part of what sustains it. It’s compressed, or yearn to get inside the cloud, a handy a shame that Schrödinger didn’t touch on reference awaits. Barbara Kiser

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fellow physicist Leo Szilard’s work on SECURITY Maxwell’s demon, a thought experiment that revealed how entropic disorder could be undone by making use of molecular- level information that looks like mere How smart connectivity statistical noise at the macroscopic level. What’s more, Schrödinger gave his code-script too much agency by imagin- is stupider by design ing that its readout was mapped directly onto the phenotype. This isn’t how it Steven Aftergood assesses a warning about the future works: you can’t read the arrangement of the Internet. of the body’s organs in the genome. The information functions as a resource, not a step-by-step guide. To acquire meaning, ardly a day now passes without in proposing what it must have context: a cell’s history and reports of a massive breach of should (but probably environment. Tracing how the phenotype computer security and the theft won’t) be done about emerges from interactions of genes with Hor compromise of confidential data. them. each other and with their environment is That digital nightmare is about to get As he notes, the key puzzle of modern genomics. much worse, asserts security technolo- security was not a What is Life? helped to make influen- gist Bruce Schneier in Click Here to Kill primary concern in tial biologists out of several physicists: Everybody, his critique of government the early design of Crick, Seymour Benzer and Maurice inertia on Internet security. the Internet in the Wilkins, among others. But there’s no The burgeoning threat, writes Schneier, mid to late twentieth Click Here to indication from contemporary reviews arises from the rapid expansion of online Kill Everybody: century. Develop- that many biologists grasped the real sig- connectivity to billions of unsecured nodes. Security and ers of early efforts, nificance of Schrödinger’s code-script as The Internet of Things, in which physical Survival in a from the US Depart- a kind of active program for the organ- objects and devices are networked together, Hyper-connected ment of Defense’s ism. Some in the emerging science of is well on its way to becoming an Internet World ARPANET onwards, molecular biology were critical. Linus of Everything. Over the past decade or so, BRUCE SCHNEIER did not anticipate the W. W. Norton (2018) Pauling and Max Perutz were both a growing number of products have been Internet’s explosive damning about the book in 1987, on the sold with embedded software and commu- growth or coming centenary of Schrödinger’s birth. Pauling nications capacity: household appliances, role in global commerce and communica- considered negative entropy a “negative cars, medical instruments and even cloth- tion. Even today, there is little incentive to contribution” to biology, and castigated ing can now be monitored and controlled prioritize security above other concerns — Schrödinger for a “vague and superficial” from afar. More of the same is on the way, so, for example, e-mails may or may not be treatment of life’s thermodynamics. as smart homes yield to smart cities and from the sender named. Perutz grumbled that “what was true in automated systems assume a larger role in his book was not original, and most of the management of critical infrastructure. SURVEILLANCE CAPITALISM what was original was known not to be The Stuxnet computer worm used to attack Surprisingly to some, much of the business true even when the book was written”. Iran’s uranium-enrichment programme of the Internet is predicated on insecurity. Although these judgements are remotely in 2010 was an early, audacious ‘Surveillance capitalism’ — the collection uncharitable, they are not without sub- indicator of the threat. of user data and its sale to advertisers and stance. Why, then, was the book so influ- Enhanced global connectivity has others — depends on vulnerable Internet ential? Rhetorical theorist Leah Ceccarelli many advantages for knowledge sharing, practices, as does intelligence collection argues that it was down to Schrödinger’s commerce and convenience. Securing it, for national security and law enforcement. writing style: he managed to bridge phys- however, is a daunting prospect. The all- Governments act as if their need to monitor ics and biology without privileging either. too-familiar vulnerability of computer the Internet can be satisfied without any But today, we can find more than that. networks — their larger compromise of security. That, writes Schrödinger’s thoughts on the entropic susceptibility to “When the Schneier, is not so. balance of life can be regarded as precur- failure, disrup- Internet starts In principle, he explains, securing the sors to studies of how biological preroga- tion and interfer- killing people Internet is straightforward, but it would tives such as replication, memory, ageing, ence by malware, it will be demand concerted government action at epigenetic modification and self-regula- viruses and other regulated.” each step. Financial incentives should be tion must be understood as processes of factors — is ampli- realigned to promote security and penalize non-equilibrium complexity that cannot fied as practically everything becomes failure by mandating that manufacturers dis- ignore the environment. It is intriguing computerized. That relentless expansion close defects in commercial software, mak- that similar considerations of environ- of cyberspace into the physical domain ing them legally liable for defects. Security ment and contingency are now seen to be brings with it new threats to power sys- should be required in new devices, and central in quantum mechanics, with its tems, mass transportation, public health rewarded through subsidies and tax breaks. ideas of entanglement, decoherence and and safety, and even political institutions, Data should be encrypted to secure them contextuality. Whether this is more than as effectively demonstrated by the Russian against unwanted collection. Critical infra- coincidence, we can’t yet say. ■ information operations that targeted the structure — power grids, communications 2016 US presidential election. and transportation — should be protected by Philip Ball is a writer based in London. Despite its lurid title, Schneier’s book bolstering network security or disconnect- His latest book, on quantum physics, is is sober, lucid and often wise in diagnos- ing them from the network altogether. Beyond Weird. ing how the security challenges posed by Government agencies are fully aware e-mail: [email protected] the expanding Internet came about, and that the expanding Internet “will create