Jul 31 2006

Global warming-5: The emergence of a paradigm

The need to take global warming seriously is not slam-dunk obvious to most people. In my own case, over time I have slowly became convinced that there was an emerging consensus among scientists studying the issue that planetary warming was a serious matter. Like most people, I do not have the time or the expertise to have studied the question in detail, but I have enough respect for the scientific process and the way that scientists make collective judgments as a community that when I see a scientific consensus emerging on anything, I tend to take it seriously. In fact the global warming issue is a great example of seeing, before our very eyes, a transition in science from a pre-paradigmatic state to a paradigmatic state.

In his book The Structure of Scientific Revolutions, Thomas Kuhn argued that during the early, pre-paradigmatic days of any scientific field, one has different schools of thought and different theories underlying them. These schools exist and function almost independently of one another. They investigate different problems, operate under different rules, and have different criteria for evaluating their successes and failures. Each develops along its own path and has its own adherents and practitioners. But at some stage, for a variety of reasons, the community of scientists coalesce around one school of thought and this becomes the dominant paradigm in that field, and all scientists start working within the framework of that paradigm.

This transition occurs at different times for different sciences. For optics, Newton’s corpuscular theory was the first paradigm. For electricity, it was Franklin’s theory. For geology, it was Lyell’s work. In biology, the Darwinian theory was the first paradigm in evolution. It should be noted that the adoption of a paradigm does not mean that the paradigms are true or that the problems in that field were solved once and for all. Newton’s optics paradigm and Franklin’s electricity paradigm were completely overthrown later, and the advent of molecular genetics resulted in the early Darwinian theory being modified to what is now called the neo-Darwinian synthesis. But the adoption of a paradigm significantly alters the way that the scientific community does its work.

Once a scientific community adopts a paradigm, the way its members work changes. Before the adoption of a paradigm, each school of thought challenges the basic premises of the others, examines different problems, uses different tools and methods, and uses different criteria for evaluation of problems. Once a paradigm is adopted however, there are no more controversies over such basics. The scientific community now tends to agree on what problems are worth focusing on, they tend to use the same terminology and tools, and they share a common understanding of what constitutes an acceptable solution to a problem. Scientists who do not adapt to the dominant paradigm in their field become marginalized and eventually disappear.

The conversion of the scientific community to a new paradigm is usually a long drawn out process with many scientists resisting the change and some never breaking free of the grip of the old paradigm. Historian of Science Naomi Oreskes gives an example:

In the 1920s, the distinguished Cambridge geophysicist Harold Jeffreys rejected the idea of continental drift on the grounds of physical impossibility. In the 1950s, geologists and geophysicists began to accumulate overwhelming evidence of the reality of continental motion, even though the physics of it was poorly understood. By the late 1960s, the theory of plate tectonics was on the road to near-universal acceptance.

Yet Jeffreys, by then Sir Harold, stubbornly refused to accept the new evidence, repeating his old arguments about the impossibility of the thing. He was a great man, but he had become a scientific mule. For a while, journals continued to publish Jeffreys’ arguments, but after a while he had nothing new to say. He died denying plate tectonics. The scientific debate was over.

So it is with climate change today. As American geologist Harry Hess said in the 1960s about plate tectonics, one can quibble about the details, but the overall picture is clear.

It should emphasized that adoption of a paradigm does not mean that scientists think that everything has been solved and that there are no more open questions. What it does mean, among other things, is that the methods used to investigate those questions are usually settled. For example, in evolution and geology, establishing the age of rocks and fossils and other things are important questions. Dating those items uses, among other methods, radioactivity. This field assumes that radioactive elements decay according to certain laws, that the decay parameters have not changed with time, and that the laws of physics and chemistry that we now work with have been the same for all time and all over the universe. This common agreement with the basic framework enables geologists and evolutionists to speak a common language and arrive at results that they can agree on and build upon.

Some creationists, in order to preserve their notion of the universe being 10,000 years old or less, have either rejected radioactive dating entirely or jettisoned parts of it, such as that the radioactive decay constants have stayed the same over time. In doing so, they have stepped outside the framework of the paradigm and this is partly why they are not considered scientists. Kuhn’s book discusses many other cases of this sort.

Kuhn argues that once a science has created its first paradigm, it never goes back to a pre-paradigm state where there is no single paradigm to guide research. Once a paradigm has been established, future changes are from thenceforth only from an old paradigm to a new one.

A key marker that a science has left a pre-paradigmatic state and entered a paradigmatic state can be seen in the way that scientists communicate with each other and with the general public. In the pre-paradigmatic stage, the book is the primary form of publication, and these books are aimed at the general public as well as other scientists, with an eye to gaining more support among both groups. As a result, the books are not too technical and there is an ongoing dialogue between scientists and the public.

But after a paradigm is adopted, scientists are freed from the need to explain and justify the basic premises of the field to a lay public, and no longer have to make a political case to justify what they are doing. They now tend to communicate only with each other. This results in them developing a more technical, insider, language and jargon that is opaque to nonscientists, and the chief means of communication becomes the technical paper addressed to similarly trained scientists and published in specialized journals. They start addressing their arguments to only those who work within their own narrow field of specialization. As a result of this increased efficiency in communication, science then tends to start making very rapid progress and the rules by which scientific theories get modified and changed become different. It now becomes much harder to overthrow an established paradigm, although it can and does still happen

But one consequence of this change in communication patterns is that, as in the global warming case, a disconnect can emerge between the consensus beliefs of scientists and the general public, and how to combat this is an interesting question.

Next: What happens to the public after a science becomes paradigmatic.

POST SCRIPT: Request for information

During the week of August 14, I will be driving with my daughter to San Francisco. Driving across the US is something I have always wanted to do to get a chance to personally experience the vastness of this country and some of its natural beauty.

We will be stopping near Denver to visit some friends on the way. I was wondering if people had any recommendations about the sights we should see between Denver and San Francisco. Here are some constraints:

1. I would like to see natural beauty as opposed to human creations. So suggestions about which national parks are worth a visit and what specific things should be seen in those parks would be most welcome.

2. We don’t have much time and I cannot hike, so the sights should be such that they are accessible using an ordinary car (not an SUV or other type of off-road vehicle).

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