"Once your eyes were thus opened you saw confirmed instances everywhere: the world was full of verifications of the theory. Whatever happened always confirmed it. Thus its truth appeared manifest; and unbelievers were clearly people who did not want to see the manifest truth; who refuse to see it" (Karl Popper)
This is the first of four planned blog entries on climate change issues. In this entry, I focus on the aspects of the climate change debate that can be viewed from a philosophy of science perspective. The philosophy of science has become less prominent from its peak in the 1950s and 1960s, when Karl Popper, Paul Feyerabend, Thomas Kuhn, and Imre Lakatos were debating with each other. But I think some of the ideas that were raised then can help us explain some of the often vociferous debate about climate change.
Climate Change and the Philosophy of Science
"Do you believe in global warming?" The question itself is perplexing, because it suggests that what is at stake is as much a matter of belief as of fact. A war is raging between two camps, both of whom claim the scientific high ground, and both of whom pick apart the flaws in their opponent's cases without acknowledging the uncertainties of their own. In short, matters are becoming polarised, with some on both sides indulging in appalling name-calling, and presenting their own respective doomsday scenarios.
Back in the 1960s, Thomas Kuhn wrote "The Structure of Scientific Revolutions", in which he described how normative science worked within a conceptual framework, and that how scientists viewed the world could not be outside a framework, even though the framework intersected the real world.
The philosopher Imre Lakatos took this idea up, and came up with the idea of a "scientific research programme". This, he argued, had a "hard core" that could cope with "exceptions" or "outliers" because they were on the margins of the framework, and could be variously explained away; they were significant, but not crucially significant in overturning the entire paradigm. This was a considerably more sophisticated and historical way of approaching the subject, as it resolved the problem at the heart of Karl Popper's "Logic of Scientific Discovery".
According to Popper, a scientific theory is only the best at the time, and is potentially falsifiable. This is the demarcation between science and non-science. A trivial example would be the proposition "all swans are white", which could not be "proven" by the observations of thousands of white swans, but could be disproven by the observation of just a single black swan.
A more sophisticated, but still simple, example would be to take the proposition that water boils at 100 degrees centigrade. Experiments taking place up mountains would indicate a lower temperature as the altitude rises. This would, in the Popper schema, both refute the original hypothesis, and challenge scientists to come up with a more sophisticated unified theory, which both explained the original result, and the evidence which falsified it.
Popper was aware, however, that the process of refutation could not be as simple as just finding examples that contradicted the theory; this he termed "naïve falsification". There could be other reasons, such as experimental error, or the theory itself could give rise to predictions. Hence the anomaly in the orbit of Uranus, according to Newtonian dynamics, could be explained as a gravitational perturbation by an unknown planet. This led to the discovery of Neptune.
Problems with the orbit of Mercury, however, led to the French astronomer Urbain Le Verrie suggesting another smaller planet which he named Vulcan, and which lay between Mercury and the Sun, was the cause, but that the difficulties of observation can caused it to remain unseen. In fact, it was Einstein's Theory of General Relatively that explained the discrepancy without the need for another planet, yet the failure to observe any such planet did not cause astronomers to treat it as an exception, refuting Newtonian dynamics, but simply as a marginal problem, which they hoped would be resolved in time within that framework. This is an example of what Lakatos described so well in his more nuanced approach to science:
Is, then, Popper's falsifiability criterion the solution to the problem of demarcating science from pseudoscience? No. For Popper's criterion ignores the remarkable tenacity of scientific theories. Scientists have thick skins. They do not abandon a theory [merely] because facts contradict it. They normally either invent some rescue hypothesis to explain what they then call a mere anomaly and if they cannot explain the anomaly, they ignore it, and direct their attention to other problems. Note that scientists talk about anomalies, [recalcitrant instances,] and not refutations. History of science, of course, is full of accounts of how crucial experiments allegedly killed theories. But all such accounts are fabricated long after the theory has been abandoned. (1)
Now to bring the matter up to date - what I think we are seeing in the conflict over global warming is a clash of two paradigms. Both have explanations for data that doesn't fit, plausible explanations, but not explanations that seem to allow any measure of doubt or uncertainty. Part if this is understandable from the psychology of the clash. The two sides have become very polarised and extreme in their presentations. Any uncertainty in one camp will be sure to be pounced up and used as a stick by the other camp.
Some scientists are aware of this problem. Judith Curry, for example, as Scientific American reported, is alarmed as what she sees as a retreat from engagement between the two sides.
Although many of the sceptics recycle critiques that have long since been disproved, others, she believes, bring up valid points-and by lumping the good with the bad, climate researchers not only miss out on a chance to improve their science, they come across to the public as haughty. "Yes, there's a lot of crankology out there," Curry says. "But not all of it is. If only 1 percent of it or 10 percent of what the sceptics say is right, that is time well spent because we have just been too encumbered by groupthink."
Curry's saga began with a Science paper she co-authored in 2005, which linked an increase in powerful tropical cyclones to global warming. It earned her scathing attacks on skeptical climate blogs. They claimed there were serious problems with the hurricane statistics the paper relied on, particularly from before the 1970s, and that she and her co-authors had failed to take natural variability sufficiently into account. "We were generally aware of these problems when we wrote the paper," Curry says, "but the critics argued that these issues were much more significant than we had acknowledged." She did not necessarily agree with the criticisms, but rather than dismissing them, as many scientists might have done, she began to engage with the critics. It was here that Curry began to develop respect for climate outsiders-or at least, some of them. (2)
What we can see here with Curry's paper is a near perfect example of what Lakatos describes in a scientific research programme, that "all programmes grow in a permanent ocean of anomalies". It is this which makes the current situation so problematic, because there is a level of uncertainty in climate change and global warming predictions, and it is debatable whether exceptions can be discounted in favour of the broader picture, or whether they are significantly large to call into question the picture of climate change. Curry herself has acknowledged that the levels of uncertainly are not always made as clear as they should be.
The critics of global warming are drawing on a different scientific research programme, and their own position has anomalies all of its own, eagerly seized upon by their opponents. But within each paradigm, there is a hard core of belief that the underlying premise - global warming as a human effect or global warming as a natural event - is the best fit for their own data sets.
It is, however, quite unusual to have such a remarkable clash. In the normal course of events, one scientific paradigm falls away because it is not as powerful in its explanatory powers to explain and predict phenomena as its successor, but here we have two systems clashing with each other, like mighty empires doing battle, rather than an empire in decline being taken over by another. Part of the reason might be the failure of both programmes to actually provide specific consequences with sufficient predictive accuracy.
Lakatos maintained that competing research programs should be appraised by reference to their relative rates of progress. If one program is stagnant, having failed to generate new confirmed consequences over a period of time during which a second program has been fertile, then the second program is superior to the first. In cases where two programs both have been progressive, as certified by applications of the incorporation criterion, appraisal requires an assessment of the relative importance of these achievements. (3)
The most notable failure of climate change scientists is to come up with any exact and falsifiable predictions, except after events. Kevin E. Trenberth has stated that: "I have given many public talks on climate change, and I have always tried to emphasize the observational facts and their interpretation, rather than the less certain projections into the future." But without any more certain projections into the future, with predictive force, while the scientific research programme is not stagnant, it is not doing as well as it could.
Either statements are made of the kind that Trenberth himself is critical of as "murky" - "while this event is consistent with what we expect from climate change, no single event can be attributed to human induced global warming", or the association of extreme weather events with global warming is made after the event. Is it any wonder that the public at large are bemused? Is it any wonder that the scientific critics attack this kind of approach? Karl Popper himself, in "Conjectures and Refutations" noted that "It is a typical soothsayer's trick to predict things so vaguely that the predictions can hardly fail: that they become irrefutable."
Contrast climate change theory with the predictive ability of Newtonian physics, Einstein's Special and General Theories of Relativity, Quantum Mechanics, and the problem becomes apparent. Events are described as "consistent with climate change" or "consistent with the existing models".
Please note that is not to say the climate change science is not happening or that global warming is not occurring, or even that it is not caused, in part, by human beings. I am not saying that.
Rather I am saying that climate models present a much weaker theory in terms of its predictive power than other theories - as can be seen (for example) from the site Green House Gas Online (4), and this is part of the problem - when global warming theory clashes with an opposing paradigm, it is much harder to make its case than theories which have what might be termed a stronger ability to do so.
(3) Theories of Scientific Progress: An Introduction. Contributors: John Losee - author. Publisher: Routledge. Place of Publication: