One of the most important points that The Sixth Extinction makes is that humans only learned about natural selection, extinction, and environmental degradation very recently. (Only a few decades ago, for instance, scientists didn’t realize that fossil fuels could change the pH of the oceans, devastating marine life.) In addition to being a study of extinction, then, Kolbert’s book is about the way science changes over time. Interpreted in this way, environmental science is a particularly clear example of the general process by which a new idea or set of assumptions—a paradigm—is introduced into the scientific community, gradually accepted within the scientific community, and is then accepted by the general public.
Kolbert cites the ideas of the science historian Thomas Kuhn in order to characterize science as a constant process of evidence gathering and “paradigm-testing.” At any given time, Kuhn argued, a scientific community will coalesce around a theory that explains a complex, real-world phenomenon. This theory—a paradigm—may be correct or incorrect. For example, in the years leading up to the career of Georges Cuvier, the European scientific community believed that different kinds of animals never died out—the concept of “extinction” wasn’t a part of the discourse. The purpose of a paradigm is to explain evidence; therefore, every new piece of evidence acts as a “test” of the paradigm. Furthermore, if a paradigm is flawed, then further evidence will tend to challenge the paradigm and show its weaknesses. For example, the abundance of fossils discovered in the 18th century slowly showed the “no extinction paradigm” to be factually incorrect.
Following Kuhn, Kolbert argues that when a paradigm becomes conspicuously weak (i.e., when it fails to support the evidence), a scientist will eventually propose a new, stronger paradigm. For example, Georges Cuvier studied the evidence of fossil remains and developed a new biological paradigm: animals go extinct over time. If a new paradigm is strong, and supports all the existing evidence—as Cuvier’s did—then the scientific community will adopt it. The final step in the process is for scientists to introduce the new paradigm to the general public in a simple, understandable way. Within a few decades of Cuvier’s theory, for example, there was an international “fossil craze,” reflecting people’s new understanding of the theory of extinction. One could even argue that, by writing The Sixth Extinction, Kolbert is participating in “paradigm popularization”; while she was not involved in the scientific discoveries described in her book, she is introducing the lay-reader to complex, cutting-edge concepts of biology and ecology.
Kuhn’s theory of paradigms is important to The Sixth Extinction because it shows that science is constantly approximating the truth. As Kolbert acknowledges, current theories of environmental change are not perfect: there are some pieces of evidence that environmental scientists cannot yet explain, and there are many questions about the environment that scientists have been unable to answer. Put another way, the current environmental paradigms are strong, in the sense that they can explain a lot of the evidence, but they need to be stronger. Thus, Kuhn’s theory of science as a constant process of evidence gathering and paradigm refining encourages the reader to go out, learn more about the environment, and develop new ideas about how to respond to the unprecedented environmental changes in the 21st century.
Science and Paradigm Shifts ThemeTracker
Science and Paradigm Shifts Quotes in The Sixth Extinction
By the middle of the nineteenth century, many of [Georges Cuvier’s] ideas had been discredited. But the most recent discoveries have tended to support those very theories of his that were most thoroughly vilified, with the result that Cuvier's essentially tragic vision of earth history has come to seem prophetic.
… if there were four extinct species, Cuvier declared there must be others. The proposal was a daring one to make given the available evidence. On the basis of a few scattered bones, Cuvier had conceived of a whole new way of looking at life. Species died out. This was not an isolated but a widespread phenomenon.
Cuvier's essay was pointedly secular. He cited the Bible as one of many old (and not entirely reliable) works, alongside the Hindu Vedas and the Shujing. This sort of ecumenicalism was unacceptable to the Anglican clergy who made up the faculty at institutions like Oxford, and when the essay was translated into English, it was construed … as offering proof of Noah's flood.
The history of the science of extinction can be told as a series of paradigm shifts. Until the end of the eighteenth century, the very category of extinction didn't exist. The more strange bones were unearthed—mammoths, Megatherium, mosasaurs—the harder naturalists had to squint to fit them into a familiar framework. And squint they did. The giant bones belonged to elephants that had been washed north, or hippos that had wandered west, or whales with malevolent grins. When Cuvier arrived in Paris, he saw that the mastodon's molars could not be fit into the established framework, a "My God" moment that led him to propose a whole new way of seeing them.
"Because of these anthropogenic emissions" Crutzen wrote, the global climate is likely to "depart significantly from natural behavior for many millennia to come."
Crutzen published "Geology of Mankind" in 2002. Soon, the 'Anthropocene" began migrating out into other scientific journals.
If, on the other hand, people were to blame—and it seems increasingly likely that they were—then the import is almost more disturbing. It would mean that the current extinction event began all the way back in the middle of the last ice age. It would mean that man was a killer—to use the term of art an "overkiller"—pretty much right from the start.
It’s only fully modern humans who start this thing of venturing out on the ocean where you don't see land. Part of that is technology, of course; you have to have ships to do it. But there is also, I like to think or say, some madness there. You know? How many people must have sailed out and vanished on the Pacific before you found Easter Island? I mean, it's ridiculous. And why do you do that? Is it for the glory? For immortality? For curiosity? And now we go to Mars. We never stop.
The Neanderthals lived in Europe for more than a hundred thousand years and during that period they had no more impact on their surroundings than any other large vertebrate. There is every reason to believe that if humans had not arrived on the scene, the Neanderthals would be there still, along with the wild horses and the woolly rhinos. With the capacity to represent the world in signs and symbols comes the capacity to change it, which, as it happens is also the capacity to destroy it.
Certainly humans can be destructive and shortsighted; they can also be forward-thinking and altruistic. Time and time again, people have demonstrated that … they’re willing to make sacrifices on those creatures’ behalf.
Among the many lessons that emerge from the geologic record, perhaps the most sobering is that in life, as in mutual funds, past performance is no guarantee of future results.