Nevertheless, there are regularities to factual change and growth: Facts will continue to grow and be overturned, albeit at a slower place, and we certainly do not seem to be leaving the exponential regime anytime soon.
But even if everything continues to grow rapidly, there might be certain limits to how we perceive this change and adapt to it.
• • •
WHEN Carl Linnaeus worked out his methodology for organizing all living things in the eighteenth century, his taxonomy had three kingdoms10—roughly translated as animal, vegetable, and mineral—and further divisions into classes, orders, genera, and species. Biologists now have five kingdoms, new subdivisions between kingdoms and classes called phyla (singular phylum), families between orders and genera, and even three larger overarching divisions above kingdoms known as domains. As our knowledge has grown from thousands of species to millions, so too has our system of classification.
Similarly, the way we categorize different diseases has grown rapidly. In 1893, the International List of Causes of Death was first adopted11 and contained about 150 different categories. As of 2012, we are up to the tenth revision12 of the International Statistical Classification of Diseases and Related Health Problems, known as ICD-10. It was released in 1990 and has 12,420 codes, which is nearly double that of the previous revision, ICD-9, which came out only a little more than ten years before ICD-10. As facts have proliferated, how we manage knowledge and think about it has also had to grow, with our classification systems ramifying in sophisticated and complex ways.
On the one hand, being exposed to more complexity, whether it be in the realm of categorization of diseases, living things, or the many other classification systems we use—from types of occupations to Internet domain names—could make us more intelligent. Just as being exposed13 to cognitively demanding television shows and video games seems to increase our ability to think critically, so too could more facts, and their attendant complex classification systems, make us smarter.
However, as humans, we seem to have certain cognitive limits on what we can know and what we can handle in our daily lives.
Our brains are only so big. And it seems that the sizes of our brains actually dictate how many social connections we can have and how many people we can regularly interact with and keep in our minds. Dubbed Dunbar’s Number, after its discoverer, Robin Dunbar, who examined the brain sizes of different primates, the number of people we can know and have meaningful social ties with seems to be limited to between about 150 and 200. This is about the number of soldiers14 that comprise a fighting unit—whether in ancient Rome or modern-day armies—and fits the size of a small village. Surprisingly, despite technological advancements in the social networking sphere, our number of Facebook friends still adheres to Dunbar’s Number and is about 190, as of 2011.15
Similarly, if we look at the number of close ties we each have, we discover another trade-off. While we know a lot of people, each of us really only has a handful of very close social ties, such as our spouse or best friend. For most people, this number is around four. In my own research I has found that as we increase the number of people we are close to,16 we lower how close we are to each of them, on average. So if I have five friends instead of four, I am less close to each of these five people than I would be if I eliminated one of them from my tight inner circle. There seems to be some sort of conservation of attention: As we increase who we pay attention to, we spread this amount of attention out evenly among these individuals.
Our brains have a certain capacity, at least when it comes to social ties. Is the same thing true for changing knowledge? Upon being confronted with his ignorance of the Copernican notion that the Earth orbits the Sun, Sherlock Holmes argued this very point:17
“You see,” he explained, “I consider that a man’s brain originally is like a little empty attic, and you have to stock it with such furniture as you choose. A fool takes in all the lumber of every sort that he comes across, so that the knowledge which might be useful to him gets crowded out, or at best is jumbled up with a lot of other things, so that he has a difficulty in laying his hands upon it. Now the skilful workman is very careful indeed as to what he takes into his brain-attic. He will have nothing but the tools which may help him in doing his work, but of these he has a large assortment, and all in the most perfect order. It is a mistake to think that that little room has elastic walls and can distend to any extent. Depend upon it there comes a time when for every addition of knowledge you forget something that you knew before. It is of the highest importance, therefore, not to have useless facts elbowing out the useful ones.”
We very likely can’t handle every piece of knowledge that comes our way, and while being exposed to more and more might help us to think better, we no doubt have our limits when it comes to dealing with rapidly changing facts. This sounds like bad news. Our brains simply won’t be able to handle all of this knowledge and information, and the rapidity at which it changes. There are workarounds, such as those mentioned in the last chapter, i.e., online search engines. But, happily, it turns out that even when rapid change happens, it’s not as overwhelming as we might think.
Many futurists are concerned with what are termed singularities, periods of such rapid and profound change due to technology that the state of the world is forever altered. Like some of the changes mentioned in chapter 7, these phase transitions happen so quickly that they can forever alter humanity’s relationship with its surroundings. The quintessential singularity that futurists dwell on is that of the potential creation of superhuman machine intelligence. While many scientists think this is either very far off or that it will never happen, how would singularities affect us? Would a singularity tax our cognitive limits or will we be able to cope?
Chris Magee, the MIT professor who studies the rapid technological change around us, and Tessaleno Devezas of the University of Beira Interior in Portugal, decided to use history as a guide.18 Focusing on two events that have already happened, Magee and Devezas decided to see how humanity has dealt with fast change. They first looked at how the Portuguese gained control over increasingly large portions of the Earth’s surface over the course of the fifteenth century, as their empire grew. They also looked at the progression of humanity’s increasingly accurate measurement of time over the last millennium or so. In both cases there were rapid shifts in certain facts, all according to exponentially fast growth and culminating in what many would argue was the crossing of some sort of singularity threshold. In the case of Portugal, the country established a nearly globe-encompassing maritime empire, and in the case of clocks, timepieces became so advanced that measurement of time was far more precise than human perceptions.
But humanity assimilated these changes quite well. When speaking about the innovation in timekeeping, Magee and Devezas wrote:
These large changes were absorbed over time apparently without major disruption; for example, no mention is made of “clock riots” even though there was resistance and adaptation was needed. In given communities, the large changes apparently happened within less than a generation.
So I think it is safe to assume a somewhat optimistic tone, recognizing that change, while it might be surprising to many of us, is not entirely destabilizing. Humans are very adaptable, and are capable of understanding how knowledge changes.
And, of course, that’s the message of this book itself.
As I hope I’ve shown, facts can change in a startlingly complex variety of ways. But far from the fluctuation in our knowledge being random, the changes are systematic and predictable. Whether about nature or about the man-made world, factual change due to measurement changes or even the identification of errors, facts change in recognizably regular ways.
In addition to looking up facts on the Internet, or to having glowing orbs on our desk that respond to changes in the market, another way to avoid the surprise of changes in knowledge is to simply rec
ognize that it’s not that surprising.
We are getting better at internalizing this. For example, many medical schools inform their students that within several years half of what they’ve been taught will be wrong, and the teachers just don’t know which half. But too often—whether because change is still too slow to notice or because of quirks in how we learn and observe our surroundings—we don’t really live our lives with the concept that facts are always changing.
In an interview, the novelist Jonathan Franzen noted: “Seriously, the world is changing so quickly19 that if you had any more than 80 years of change, I don’t see how you could stand it psychologically.” Many of us still maintain this attitude, unable to deal with change. But it doesn’t have to be this way. We have to begin actually educating ourselves and our children to recognize that knowledge will always be changing and showing the regularities behind how these changes can happen. More important than simply learning facts is learning how to adapt to changing facts. Until we begin to do that, we are going to continue to be caught flat-footed by new information.
Facts don’t change arbitrarily. Even though knowledge changes, the astounding thing is that it changes in a regular manner; facts have a half-life and obey mathematical rules. Once we recognize this, we’ll be ready to live in the rapidly changing world around us.
ACKNOWLEDGMENTS
An unbelievable number of people have been instrumental in making this book a reality. In the world of science I have had a great number of supporters and mentors. While it would be nearly impossible to list everyone, I would like to single out Steve Strogatz and Nicholas Christakis. Steve, my graduate school adviser, is a great mentor and friend, and a collaborator on numerous research projects. In addition, he encouraged me in writing and even provided me with my first opportunity to write for a large audience, at the New York Times. Nicholas Christakis, whose group I was a part of while a postdoctoral fellow, has also been a wonderful collaborator and friend, as well as acting as a mentor in both my research and writing. I have been privileged to work with such amazing scientists and writers, who nurtured the highly interdisciplinary and unorthodox path I have chosen for myself.
I have also had a number of supporters in the writing world. Gareth Cook, my former editor at the Ideas section of the Boston Globe, discovered my early writing and nurtured my skills. Both Gareth and Steve Heuser, the current editor of Ideas, also presided over the publication of my article about mesofacts that first got this whole book-writing process going. Thanks go to both the Boston Globe and The Atlantic, where I was given the opportunity to write several articles that have been adapted here. David Moldawer, who bought this book when it was a mildly coherent shell of what it hopefully has become, also deserves my thanks.
I have had the pleasure of having many supportive readers of early drafts, who also brought various concepts and articles to my attention. Thank you to Avi Gerstenblith, Paul Kedrosky, Jukka-Pekka Onnela, Jason Priem, Niels Rosenquist, and Josh Sunshine.
K. Brad Wray deserves thanks for introducing me to so many ideas in the philosophy of science, including the fallacy of Planck’s Principle, in addition to taking the time to read an entire draft of this book and providing incredible feedback. Ari Cohen Goldberg deserves my thanks for providing a great deal of expertise in the realm of language. Thanks to Brian Switek for talking with me about how our knowledge about dinosaurs has changed in the past several decades, making sure I didn’t get too much wrong about dinosaurs, and spending longer than anyone else I have spoken with reminiscing about the brontosaurus. In addition, both Brian and Ari were instrumental in shaping my thinking about the generational component of knowledge change, each independently bringing it to my attention. Sarah Gilbert and Rena Lauer were also instrumental in helping with my questions about medieval Europe.
Countless people have also pointed me to articles and ideas, and supported me in numerous other ways during this process. Thank you to everyone.
Of course, if you’ve gotten this far, you know that facts become out-of-date and errors propagate. Therefore, it’s only natural for me to inform the reader that any errors are, of course, my own. You have been so warned.
I owe a great deal of appreciation to Max Brockman, my agent, for having brought me into the world of book writing and providing advice throughout. Courtney Young, my editor, shepherded this book at every stage and has earned my perpetual gratitude. And Niki Papadopoulos, you joined the editing process at the very end but have been a great help in making sure that the book ended up being the best version possible, and actually got it out the door.
My parents have been supportive of this project all along, having read multiple drafts, for which I am incredibly appreciative. But more important, they instilled in me a love of learning. I have strived to live by their daily exhortation to me before heading off to elementary school: “Think, have fun, and be a mensch.”
My grandfather, Irwin Arbesman, in addition to allowing me to kick off the book with a great story, is an amazing sounding board for all of my ideas, and has provided wonderful feedback during this entire process. I owe him a great deal of thanks.
And, last, I’d like to thank my wife, Debra. She has been incredibly supportive and proud of me at every stage. She read so many drafts, giving comments on each, and has been willing to listen to me speak about the topics in this book over and over, ad nauseam (at least for her). Debra, you are truly an eishet chayil.
NOTES
CHAPTER 1: THE HALF-LIFE OF FACTS
1. “the diploid chromosome number of 48 in man”: Martin, Aryn. “Can’t Any Body Count? Counting as an Epistemic Theme in the History of Human Chromosomes.” Social Studies of Science 34, no. 6 (December 1, 2004): 923–48; Tjio, Joe Hin and Albert Levan. “The Chromosome Number of Man.” Hereditas 42, no. 1–2 (1956): 1–6.
2. But in 1956, Joe Hin Tjio and Albert Levan: Gartler, Stanley M. “The Chromosome Number in Humans: A Brief History.” Nature Reviews Genetics 7, no. 8 (August 2006): 655–60.
3. Certain fields use fact to mean an objective truth: Philosophers of science will no doubt view my definition of facts and knowledge as distinct from underlying truth as overly simplistic. However, I do not mean that they are separate from some objective scientific truth, simply that they are approaching this truth, as I make clear. In addition, I adhere to the perspective that such an objective scientific truth does exist independent of our minds, and I am quite optimistic that we can move toward it. But, as I discuss further, lots of different types of knowledge change in similar ways, and it is therefore a powerful technique to view them all jointly.
4. by bundling all of these types of facts together: A fact and how it changes is ultimately about people: we learn about it from others; we discover it, often by choosing what we wish to explore; and sometimes it is true only because of others.
So let’s classify the ways that knowledge changes into four rough categories:
1. What we, as a society, know about the world can be updated.
2. What is true of the world can itself change.
3. As an individual, we can update what we know.
4. As a smaller group of individuals, we can update what we know.
For example, the correction of the number of human chromosomes is an example of the first category. How many billions of people are on the planet is in the second category, as is which computer is the world’s most powerful. The third category is simply how we assimilate the first and second categories, sometimes with delays of years or decades, such as in the case of the existence (or not) of the brontosaurus. The fourth category is about how groups of people receive information as it spreads over time, such as when we learn something new, perhaps through the grapevine.
Of course, these are not particularly clear or distinct. Often they are intertwined. For example, the brontosaurus is a little bit of numbers one and three, and even some of fo
ur (paleontologists as a group changed faster than the general populace). Which areas of the world were infected with the Black Death involved numbers two and four. And my surprise at discovering that we will hit seven billion people on the planet by the end of 2011 is a combination of numbers two and three.
5. which I call mesofacts: Mesofacts make up what has been called the invisible present:
All of us can sense change—the reddening sky with dawn’s new light, the rising strength of lake waves during a thunderstorm, and the changing seasons of plant flowering as temperature and rain affect our landscapes. Some of us see longer-term events and remember that there was less snow last winter or the fishing was better a couple of years ago. But it is the unusual person who senses with any precision changes occurring over decades. At this timescale, we are inclined to think the world is static, and we typically underestimate the degree of change that does occur. Because we are unable directly to sense slow changes, and because we are even more limited in our abilities to interpret their cause-and-effect relations, processes acting over decades are hidden and reside in what I call “the invisible present.” (Magnuson, John J. “Long-term Ecological Research and the Invisible Present.” Bioscience 40 [1990]: 495–501.)
CHAPTER 2: THE PACE OF DISCOVERY
1. When Derek J. de Solla Price arrived: Garfield, Eugene. “A Tribute to Derek John de Solla Price: A Bold, Iconoclastic Historian of Science.” In Essays of an Information Scientist, ISI Press. Vol. 7, p. 213.
2. Price published his findings: Price, Derek J. de Solla. “Quantitative Measures of the Development of Science.” Archives Internationales d’Histoire des Sciences 4, no. 14 (1951): 85–93.
3. Little Science, Big Science: Price, Derek J. de Solla. Little Science, Big Science—and Beyond. New York: Columbia University Press, 1986.
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