The Half-Life of Facts (30 page)

While ongoing scientific inquiry is one solution to improving knowledge and rooting out error, the diffusion of accurate facts is far from instant or guaranteed. For example, many retracted scientific papers are still cited years after they have been retracted. The number of citations may drop quite rapidly once a finding is retracted, but it can still be cited long after the study has been discredited or otherwise rendered obsolete. I’d like to think we’re getting better. It’s easier than ever before to look things up online or to correspond with experts. But as knowledge continues to expand, it becomes harder to be keep track of all the changes.

Since
The
Half-
Life of Facts
was initially published, I’ve had the wonderful experience of corresponding and discussing the book with readers, from physicians, teachers, and academics to many others, including experts in opera and those interested in religious history. You’ve been instrumental in how I think about change, sharing similar stories with me about the difficulty in adapting to new knowledge, and allowing me to learn how the ideas in my book can be applied to a whole host of fields. And one of the most exciting experiences so far has been learning about new bits of knowledge related to what I discuss in my book. One intriguing case is related to my discussion of a somewhat less-than-pressing issue: the health benefits of spinach.

On
page 83
of the hardcover edition of this book, I discuss the measurement of the iron content of spinach. This measurement was taken back in the nineteenth century, but a crucial decimal point was transposed in its recording. Consequently, for decades people thought that spinach had ten times more iron than it actually did. In the early 1980s, an eminent physician published a paper in the
British Medical Journal
, aptly and tersely titled “Fake!,” in order to root out such errors:

After tracking down this paper, I shared this story in
The
Half-
Life of Facts
as one of many examples about how knowledge grows and changes. But, in a perfect illustration of how error works in real time, this story about correcting a scientific error itself is erroneous.

According to Mike Sutton, a reader in criminology at Nottingham Trent University with a keen interest in debunking error, confusion between iron oxide and iron, or perhaps some experimental contamination—rather than a typographical mistake—led to the error about the high iron content of spinach. Just like the DeLorean hoax, the error was discovered and corrected relatively rapidly, in this case by the early twentieth century. But just as the original error was still cited years later (so some of the claims about the error’s persistence seem to be true—the story is wonderfully complicated), the erroneous myth-busting in the medical journal was also cited for decades. The confusion of the iron content of spinach was finally unpacked and debunked in 2010—29 years later!—by Sutton and even later acknowledged by the original journal author. However, I didn’t find out about the error and its correction until after my book had already gone to press. If you happened to have read my book without knowing about this, you would have the wrong fact in your head.

Far from being disconcerting, however, the fact that this error was printed in my initial edition is exciting.

It would be so convenient and predictable if all knowledge stood the test of time. As it should be clear by now, if creating
everlasting knowledge were the measure of being a scientist, then no one would want to be a scientist. No one would explore or write or even be willing to read about our latest findings. Of course, we still have to be scrupulous, but the good news is that while knowledge is fickle and changing, the way it changes does obey rules and regularities. There is a method to the madness.

I have endeavored to correct the error of the spinach myth, as well as a number of other incorrect and outdated facts, for this paperback edition. My community of readers has been essential in pointing out my own gaps in knowledge: You’ve made this book the best version possible! From rooting out errors to updating what the scientific and scholarly community has learned, what we think we know is constantly changing.

It’s a certainty that facts in this book will eventually become outdated. Based on how information spreads, some of them already are. But thanks to the subject matter of my book, I can not only own up to these mistakes, but rejoice in them. Because, happily, even as information changes over time, as does certain knowledge in my book, the overall message—that knowledge can, should, and does change—remains ever accurate.

Ultimately, science is far from clearly linearly progressive—witness the switchbacks and wrong turns in every century.

I’m reminded of a story an ecology and evolutionary biology professor of mine once shared. On Tuesday, he gave a lecture on the size distribution of trees in forests. The following day, he read a paper that invalidated what he had just taught his students the day before. On Thursday, he once again faced those same students, showing them the new finding. “Remember what I told you on Tuesday?” he asked. “Well, it’s wrong. And if that worries you, you need to get out of science.”

I invite readers to continue the conversation and get in touch with me at http://halflifeoffacts.com. I welcome any and all corrections to this book. We live in this exciting world of changing knowledge, so let’s go exploring.

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. In addition, I’d like to acknowledge
Wired Opinion
, which published an article I wrote on the myth of iron in spinach that has been adapted here as part
of the Afterword. And, of course, I’d like to thank readers of the hardcover edition of this book for providing valuable feedback and updates. 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
.

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.

1      
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.

5      
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.

5
      
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:

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 four (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.

6      
which I call
mesofacts:
Mesofacts make up what has been called the
invisible present
: