The Knowledge: How to Rebuild Our World From Scratch

by Lewis Dartnell

  Such a barometer can be built out of any glass tube—and the elegance of such an arrangement is that it is naturally invariant in relation to the diameter of the tube used (as long as the diameter is constant along its length). The thicker the mercury column the more weight is pulling it down, but this is perfectly balanced by the increased force of atmospheric pressure pushing it back up—any mercury-column barometer will immediately give you the same answer, regardless of the details of its construction.

  Once a novel instrument becomes available, it offers an unprecedented means for investigating the world and often leads to a rapid burst of new discoveries. For example, try hiking your new barometer up a mountain to explore how atmospheric pressure changes with altitude, or look for patterns and correlations between the finely fluctuating air pressure at your location and the weather. Medics today still quote blood pressure in units of the height of a corresponding mercury column: around 80 mmHg is the normal value between heartbeats.

  Measuring temperature demands a little more cunning. The temperature of different objects is revealed to us by our own senses—we can feel whether something is hot or cold. But how do you build a device to precisely measure that subjective experience, to put a number on something’s hotness? The trick is to look for physical effects that correlate with your personal sensation: you’ll notice that as substances get hotter they also often expand. The next step then is to build a device designed to exploit this physical phenomenon for an objective expression of temperature. A simple heat-sensing device can be constructed with a long thin tube of glass, partially filled with liquid, and then sealed at both ends—such an arrangement maximizes the visible effect of expansion. Strap the tube to a ruler, and the height of the top of the fluid column provides a proxy for the temperature encountered. You can now measure the temperature of objects relative to each other, independent of your subjective perception.

  But the fluid column height seen at different temperatures in a particular instrument, and thus the measurement you get, will be entirely dependent on the dimensions and other idiosyncrasies of its construction (unlike the simple barometer we already looked at): you won’t be able to compare your results against anyone else’s. What you need is a standardized scale that anyone can derive and mark on their own instrument. And for that you need a way of determining fixed points: events or states of matter that always occur at exactly the same temperature and so can serve as a thermometric benchmark. It seems natural to base a temperature scale on water, as the changes in state of this substance occur over a range relevant to everyday life—from an icy winter’s morning to a steaming saucepan. Once you’ve got an upper and lower fixed point nailed down, it’s then a simple matter of regularly subdividing the range in between into a convenient round number of graduations to give a meaningful temperature scale. The Celsius scale is based on the freezing and boiling of water* as fixed points, defined to occur at 0 and 100 degrees, respectively. But rather than using water itself as the fluid, you’ll realize that mercury expands far more uniformly for an accurate thermometer. For thermometers capable of operating at temperatures beyond the boiling point of mercury, for use in a kiln or furnace, for example, you will need to exploit other physical phenomena. Your investigations of electricity, for instance, will reveal that the resistance of a wire often increases with temperature.

  THE SCIENTIFIC METHOD—CONTINUED

  This, then, is the fundamental process for devising reliable means for measurement of any attribute. As the recovering civilization discovers strange new phenomena of nature, new fields of scientific research emerge. Means of isolating the properties of these phenomena and translating them into something that can be reliably measured must be devised before they can begin to be understood and exploited for technological applications. For example, when electricity was first stumbled upon, investigators struggled to quantify the properties of this new phenomenon, resorting to subjectively rating the intensity of the shock they received. But as the phenomenon was investigated, some of its repeatable effects were noticed and could then be employed for measurement—using the motor effect to deflect a needle around an ammeter dial, for example. And these scientific instruments aren’t just gizmos for the laboratory: they are also the thermometer that reveals your child’s fever, the meter monitoring the flow of electricity into your home, the seismometer serving as a sentinel for foreshocks presaging a larger earthquake, or the spectrometer detecting trace indicators in your hospital blood test.

  These devices for measuring the world, and the standardized units they count in, are the basic tools of science. Knowledge of the world can be gleaned only by attentively inspecting it, or even better, by carefully arranging contrived circumstances to investigate a particular aspect in detail. This is the essence of the experiment.

  An experiment is a way of artificially constraining a situation, to attempt to remove other distracting or complicating factors so you can focus tightly on how just a few features behave. An experiment is asking a clearly worded question of the universe and eagerly watching how it responds. Experimentation addresses the dissatisfaction with what nature happens to display for you, and forces it to reveal tightly defined facets of itself as you poke in different ways. Once you have controlled all the complicating factors and pinned down just one, you’ll then move on to the next, and so on, systematically interrogating the system until you understand how all the parts fit together.

  As well as your instruments to extend the human senses and to measure the results of different tests—a thermometer, a microscope, or a magnetometer—the meticulously constrained scenario demanded by a particular experiment often requires new contraptions: specially constructed scientific equipment designed to create specific conditions for you to study. Just as important, observations and results of your experiments need to be recorded numerically—adorning qualitative descriptions of what happened with measured, quantitative precision. But far beyond merely using enumeration to accurately compare different outcomes, the language of mathematics can be adopted as a powerful tool for precisely describing the behavior and patterns of nature, and the interrelationships between her parts. An equation summarizes a complex reality into its condensed essence. The upshot is that you can calculate the expected outcome in new, unobserved situations—you can make precise predictions.*

  But for all of its careful observations, intricate experiments, and condensed equations, the absolute essence of science is that it offers a mechanism for you to decide which explanation is most likely to be the right one. Anyone with imagination can construct a tale that neatly accounts for the ways of the world—where rain comes from, what happens when something burns, or how the leopard got its spots. But these are no more than entertaining diversions—etiological Just So stories—unless you have a reliable way of selecting which one is more likely to be correct.

  Scientists construct a best-guess story based on their prior knowledge and what’s already been established, called a hypothesis, and design particular experiments targeted to test different predictions of this story—systematically poking and prodding the hypothesis to check how well it works, or to inform the choice between competing proposals. And if this account withstands the tests of experiments or observations many times, and is not found wanting, then it becomes a well-founded theory and we can have confidence in using it to explain other unknown aspects. But even then, no theory is ever inviolate: it could itself be torn down later, undermined perhaps by new observations that it cannot account for, and replaced by an explanation that offers a better fit to the data. The essence of science lies in repeatedly admitting you were wrong and accepting a new, more inclusive model, and so, unlike other belief systems, the practice of science ensures that our stories become steadily more accurate over time.

  In this way, science isn’t listing what you know: it’s about how you can come to know. It’s not a product but a process, a never-ending conversation rebounding back and forth between
observation and theory, the most effective way of deciding which explanations are right and which are wrong. This is what makes science such a useful system for understanding the workings of the world—a powerful knowledge-generating machine. And this is why it is the scientific method itself that is the greatest invention of all.

  But in the hardships of a post-apocalyptic world, you’ll not be immediately concerned with accruing knowledge for its own sake—you’re going to want to apply that understanding to helping improve your situation.

  SCIENCE AND TECHNOLOGY

  The practical application of scientific understanding is the basis of technology. The operating principle of any technology exploits a particular natural phenomenon. Clocks, for example, utilize the discovery that a pendulum of a particular length always swings with the same rhythm, and this reliable regularity can be used to meter time. The incandescent light bulb capitalizes on the fact that electrical resistance causes wires to get hot, and that very hot objects emit light. In fact, anything but the simplest technology exploits a whole collection of different phenomena, controlling and orchestrating the various effects to achieve a designed purpose. New technology invariably builds on older ones, borrowing previously developed solutions for providing particular functions, like off-the-shelf components. It is often only the ingenious new combination of established parts that is novel in an invention, and we’ve looked closely at two examples: the printing press and the internal combustion engine. Each new technology offers a novel function or advantage, which can in turn itself be incorporated into further innovation—tech begets more tech.

  As we have seen throughout this book, history has witnessed the intimate interaction of science and technology. Researchers discover an unknown phenomenon, principally by demonstrating that an observation cannot be explained by any known phenomena, and then explore its different effects and learn how to maximize and control them. Harnessing these extra principles allows the creation of tools or other inventions to ease human toil or enrich everyday life—the process of turning oddity into commodity. Exploiting novel principles also allows the building of new scientific instruments and experiments, to scrutinize and measure nature in fresh ways, and so drive yet more fundamental discovery and the unearthing of further natural phenomena. Science and technology are in a close symbiotic relationship—scientific discovery drives technological advance, which in turn enables further knowledge-generation.

  Not all innovations draw directly on recent discoveries, of course—the spinning wheel is a product of pragmatic problem solving—and even the celebrated poster boy of the Industrial Revolution, the steam engine, was initially developed predominantly through empirical know-how and the practical intuition of the engineers rather than theoretical considerations. And indeed, there are examples in our history when inventors didn’t correctly understand the operating principle behind their creation, but it worked nonetheless. The practice of canning food for preservation, for example, was developed long before the acceptance of germ theory and the discovery of spoilage by microorganisms.

  Even with the correct scientific understanding of the phenomena involved, producing a working invention demands far more than a single leap of imaginative creativity. Any successful innovation requires a long gestation period of tinkering and debugging the design before it works reliably enough to be adopted widely—this is the 99 percent perspiration that the American inventor Thomas Edison described as following the 1 percent inspiration. The same process of rigorous, methodical investigation that drives science is applied here as well, analyzing in this case not the natural world but our own artificial constructs—experimenting with nascent technology to understand its shortcomings and improve its effectiveness.

  Survivors of the Fall will appreciate the importance of scientific understanding and critical analysis, which will be crucial in maintaining relic technology as long as possible. But over the generations the post-apocalyptic society must protect itself against slipping into a rationality coma of superstition and magic, and must nurture an inquisitive, analytical, evidence-based mind-set for the rapid attainment of their own technological capability. This is the flame that the survivors must keep burning. It is by thinking rationally that we have been able to vastly improve our productivity in growing food, to master materials beyond sticks and flint, to harness power sources beyond our own muscles, and to build transportation to convey us much farther than our own feet ever could. It is science that built our modern world, and it is science that will be needed to rebuild again.

  FINALE

  THIS BOOK CAN OFFER only glimpses of the vast architecture of current understanding and technology. But the areas we explored will be the most critical for nurturing a nascent culture through an accelerated reboot and enabling it to relearn all else. My hope is that by seeing just how civilization actually gathers and makes all the fundamentals we need, you’ll come to appreciate, just as I have during the research for this book, the things we take for granted in modern life: bountiful and varied food, spectacularly effective medicines, effortless and comfortable travel, and abundant energy.

  Homo sapiens first had a marked effect on the planet around ten thousand years ago, with the sudden disappearance of around half of the world’s large mammal species—we are the prime suspect for driving this extinction with our teamwork and improved hunting technology of stone axes and tipped spears. Over the next ten thousand years there was a steady deforestation around the Mediterranean Sea and northern Europe as people settled and cleared the surrounding land. Three hundred years ago the human population began to grow rapidly, and gradually every scrap of land that was suitable for agriculture became cultivated. There were also profound changes not just to the landscape, but to the chemistry of the entire planet, as hundreds of millions of years of accumulated carbon was dug out of the ground and pumped into the atmosphere with mounting fervor. The rising carbon dioxide levels in the atmosphere pushed the very climate of the world, driving global warming, rising sea levels, and acidification of the oceans. Dotted towns and cities swelled and coalesced with each other like bacterial colonies, as roads were draped like ribbons across the rolling landscape, looped into rings around large urbanizations, and tangled up in gloriously complex overpasses at major interchanges. A growing swarm of metallic craft hurried back and forth over the land and seas of the world, crisscrossing the skies, and some even piercing out of the atmosphere. At night this ceaseless fervent activity was apparent from space, with the continents marked out in webs of artificial lights, networks of glowing nodes and lines.

  And then silence.

  The worldwide network of traffic abruptly halts, the web of light fades and dies, cities rust and crumble.

  How long will it take to rebuild? How quickly can technological society recover after a global cataclysm? The keys to rebooting civilization may well be within this book.

  THE-KNOWLEDGE.ORG

  Explore the book’s website for further material, recommendations, and videos, and continue the debate on the community page:

  What knowledge would you preserve?

  @KnowledgeCiv

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  FURTHER READING AND REFERENCES

  A small selection of books discussing the historical development of science and technology have proved absolutely indispensable through many of the chapters of this book, and I would recommend these as excellent texts for reading around the themes of The Knowledge:

  W. Brian Arthur, The Nature of Technology: What It Is and How It Evolves.

  George Basalla, The Evolution of Technology.

  Peter J. Bowler and Iwan Rhys Morus, Making Modern Science: A Historical Survey.

  Thomas Crump, A Brief History of Science: As Seen through the Development of Scientific Instruments.

  Patricia Fara, Science: A Four Thousand Year History.

  John Gribbin, Science: A History: 1543-2001. />
  John Henry, The Scientific Revolution and the Origins of Modern Science.

  Richard Holmes, The Age of Wonder: How the Romantic Generation Discovered the Beauty and Terror of Science.

  Steven Johnson, Where Good Ideas Come From: The Natural History of Innovation.

  Joel Mokyr, The Lever of Riches: Technological Creativity and Economic Progress.

  Abbott Payson Usher, A History of Mechanical Inventions.

  Many of the themes of this book, including the conditions of the post-apocalyptic world and recovering from rudimentary means, have also been explored in novels, and here are a few that are well worth recommending. Both Daniel Defoe’s Robinson Crusoe and Johann David Wyss’s The Swiss Family Robinson tell stories of ingenious survival after being knocked back to basics after a shipwreck. Mark Twain’s A Connecticut Yankee in King Arthur’s Court recounts the efforts of an accidental time traveler, and Island in the Sea of Time by S. M. Stirling describes how the whole population of an island thrives after being transported back to the Bronze Age by an unexplained event. George R. Stewart’s Earth Abides follows a community recovering from an apocalypse delivered by plague, whereas John Christopher’s The Death of Grass covers the catastrophe wrought by disease that doesn’t affect humanity directly, but kills all grass species. Cormac McCarthy’s The Road is a brutal tale of father and son struggling for their lives in the lawless aftermath of an unspecified cataclysm, and Algis Budrys’s Some Will Not Die and David Brin’s The Postman deal with the struggle for power after the collapse of civilization, whereas Richard Matheson’s I Am Legend tells the story of the last surviving human. Pat Frank’s Alas, Babylon and Nevil Shute’s On the Beach both describe the immediate aftermath of a nuclear war, whereas A Canticle for Leibowitz by Walter M. Miller Jr. considers the preservation of ancient knowledge centuries after a nuclear holocaust. Riddley Walker by Russell Hoban also looks at society generations after an apocalypse, but one that has regressed to a nomadic existence. Margaret Atwood’s two post-apocalyptic novels, Oryx and Crake and The Year of the Flood, as well as Jack McDevitt’s Eternity Road and Kim Stanley Robinson’s The Wild Shore, also present fascinating visions of life in a post-apocalyptic world. Also well worth reading are the anthologies of post-apocalyptic fiction: The Ruins of Earth (edited by Thomas M. Disch), Wastelands: Stories of the Apocalypse (ed. John Joseph Adams), and The Mammoth Book of Apocalyptic SF (ed. Mike Ashley).