Karl Popper and Antarctic Ice
The Climate Debate and Its Problems
By Peter Borah, Class of 2012
The John Crerar Foundation Science Writing Prize for College Students, first awarded in 2004, is given to a paper “on a scientific topic, which is thorough in its arguments but accessible to a broad readership.” Two prizes are awarded each year.
The second-place winner this year was “The Oceanic Acid Trip: Why CO2 impacts the oceans so drastically,” by Michael Roytburd, AB’10. Below is the full text of the first-place paper, by Peter Borah, Class of 2012. (This version differs slightly from the winning essay; a small factual error has been corrected.)
The importance of science and technology to everyday life in the twenty-first century has led to highly public and controversial debates on a number of important scientific issues. One key example is global climate change. No longer a mere technical question to be resolved through the ordinary methods of scientific research and peer-reviewed papers, “global warming” has become a political issue, with laypeople from all parts of the political spectrum holding strong opinions on the issue. The debate, however, often reflects a basic lack of understanding of the scientific process. The neat, cut-and-dried talking points from either side cannot do justice to the tremendously complex body of research that ultimately forms the basis for scientific consensus. In this paper I examine one such talking point, the growth of Antarctic ice, and attempt to show that we as a public need a far more nuanced account of science before we can properly analyze global climate change; or, for that matter, any scientific question at all.
Perhaps the best place to start is with a brief excursion into my own field, the philosophy of science. In 1934, Karl Popper published his highly influential book, The Logic of Scientific Discovery. Popper's insight is both simple and highly persuasive. It is a reaction to the well-known “problem of induction,” which simply states that observation can never provide enough evidence to prove universal statements (such as scientific laws). This problem dates back to the eighteenth-century philosopher David Hume, and is well illustrated by an anecdote attributed to Bertrand Russell. Imagine a turkey who is trying to determine how humans deal with his kind. He reasons to himself, “Every day, a human comes and gives me food. This has happened so many times that it must always be true. Tomorrow I will again be fed.” Unfortunately, the next day is Thanksgiving, and our poor misguided poultry is killed and eaten instead. This general problem was a big issue for the dominant philosophical school of the time, Logical Positivism, which believed that you actually could get from observation to universal statements.
Popper thought that we ought to turn this whole thing on its head. Instead of trying to prove theories correct, he suggested that a scientist's job is to try to prove them incorrect. The best theories are ones that make lots of predictions which can be checked against the facts. Throwing out theories which made incorrect predictions and creating new ones to take their place is, in this view, the driving force of science. There is a lot to like about this account. It is simple, doesn't suffer from the problem of induction, and seems to capture a lot about the self-criticizing nature of science. It was so persuasive, in fact, that it made its way out of the philosophy of science and into the consciousness of the general public. Whenever you hear someone talk about whether a theory is “testable” or “falsifiable,” they are implicitly referencing Popper.
However, 1934 was a long time ago, and philosophers of science have found that things are not nearly as straightforward as all that. One influential strand of critique was launched by Thomas Kuhn in 1962, with The Structure of Scientific Revolutions. Kuhn relied on the history of science to show that matters were far more complicated than Popper believed. Determining exactly what predictions a theory makes is not always straightforward, and even the facts that these predictions are tested against may often be in question. In addition, a single “anomaly” is almost never sufficient to disprove an entire scientific theory. Rather, it takes a large number of problem to bring scientists to the point where they have to scrap their theory and build a new one. Like Popper, Kuhn's work also had an impact outside of academia. The phrase “paradigm shift,” for instance, comes directly from Kuhn. However, it was far from being enough to displace the importance of Popper. To this day, you can ask any working scientist what the scientific method is, and he or she is likely to give you a very Popperian account.
The discussion so far may seem unnecessarily theoretical. However, the philosophical background is crucial because the debate over global warming involves exactly these issues, and understanding them allows us to criticize the talking points and see how they differ from the actual practice of science. Enough philosophy, then. On to the science!