On the Nature of Science

written by Karen Street for the workshop, Friends Process: Responding to Climate Change
co-led by Gretchen Reinhardt and Karen Street at Friends General Conference, 2013

What is Science?

Most natural scientists share Karl Popper’s picture of a discipline where ideas cannot be proved, but they can be disproved. As ideas are challenged time and again, as they survive the challenges, they gain credibility. Potential challenges are often proposed along with the ideas. With the introduction of the Standard Model of Fundamental Particles and Interactions (quarks and stuff), scientists identified one kind of particle as a possible weakness in the model, and testing began there. Many in science consider ideas which are not falsifiable (string theory, as of today) as falling outside science.

In order to be falsifiable, a model must make predictions. A simple example: new satellites, and not just the ones Newton could see, would follow the same laws of motion. Explanations of dark matter predict the size and mass of particles.

Science is unique in my experience in punishing fraud (chances are you lose your funding forever). Making mistakes in your field is allowed, if you confess to it and are polite (in public anyway), but if you say things in your own field that have been shown to be false, you pretty much lose the respect of the science community. Linus Pauling, often presented as an example of what happens when a great man speaks outside his field of expertise, shows that scientists, like everyone, are allowed to talk trash about Vitamin C and the dangers of atmospheric testing of nuclear weapons if those are not their fields of research. Factual errors disappear relatively quickly from scientific conversations, most rapidly within the field, but relatively soon among other scientists as well. I remember one FB friend, a prominent science writer, taking down a posting he learned was wrong; that behavior is so unusual among non-scientists, I remember it.

For our time together, we will use the narrowest definition of science, that it is about the physical world and can be tested in the physical world. As a result, references to science in this handout exclude much of economics and other social sciences and psychology.

Scientific Consensus

Consensus in popular use: Kerry wants to order Chinese and Bob wants Italian and they reach consensus on hamburgers. Scientific consensus is different. It might help to consider scientific consensus a purer form of Friends Unity: 100% agreement is not required, but challenges ARE—no important idea is considered part of scientific consensus unless it has survived challenge.

Sometimes people with non-mainstream ideas (CO2 might not be to blame for global warming; T-cells have nothing to do with AIDS) complain that scientists aren’t as open-minded as they are. In fact, science is very receptive to ideas that challenge conventional thinking; these ideas are more likely to get Nobel Prizes. This leads to publishing bias, the tendency to publish what challenges rather than confirms and thus gives a distorted idea of what scientists are finding in the lab. Scientists recognize this as a problem, but since they are most interested in what challenges their thinking, it goes to a lower priority.

Scientific consensus is reached when scientists lose interest in exploring an idea, because it has been challenged unsuccessfully in so many ways, so many times, that the idea looks pretty solid, especially basic ideas like evolution and the effect of greenhouse gases. Consensus generally is not used to describe what everyone believes unless those beliefs have been challenged and survived (eg, the belief was once common that ulcers are never caused by bacteria, but in the absence of challenge, it would not be considered consensus). Scientists no longer explore whether evolution occurs, but there are many aspects of evolution considered exciting and open. Many parts of climate change science discussed often among the public (Is Earth warming? Is CO2 definitely a factor? Could it be the sun?) are not interesting questions to scientists, as they were settled long ago. If information does emerge that indicates that the consensus is wrong, the consensus is reconsidered, eg, Newton’s laws do not work outside the universe we see of medium-sized masses and low speeds.

On the other hand, there are fields where expert guesses may coalesce around certain values, yet no consensus exists. Mainstream predictions for sea level rise this century range from 80 cm to 2 meters (2.5 to 6.5 feet) but there is no consensus because there are too many questions and challenges. The contribution from ice sheet melt, which may (or may not) contribute the largest portion of sea level rise this century, was omitted from the 2007 Intergovernmental Panel on Climate Change report for that reason.

A frequent argument from outside science is that scientists use consensus instead of data. There is no consensus without data. Others argue that consensus requires 100% of scientists (or even the public) to agree. There were still scientists disagreeing with a sun-centered solar system more than a century after Galileo, but Newton, born the year that Galileo died, assumed the Earth went around the sun in his work. Heliocentrism was established as fact among scientists by the time Newton became aware of the issue, yet at his death, scientists could still be found clinging to the old view. See Steven Sherwood’s article in Physics Today, Science controversies past and present, for parallels between how long it takes to get 100% of scientists to accept climate change and other major ideas in science.

Media coverage of medicine, social science and psychology often reports first results breathlessly, long before there is consensus, making it sound like scientists are always changing their minds.

How Scientists Communicate Results

Scientists consider peer-reviewed (reviewed first by equals, other scientists in the field) publication necessary but not sufficient to be included in the scientific discussion. If you don’t submit your work to peer review, you aren’t asking anyone in science to consider your ideas. After initial peer review, some papers are given closer scrutiny by experts in the field. During that second level of review, some fields of medicine and the life sciences are notorious for how much published work is found to have inadequate information and analysis to support conclusions. Further research is done on some ideas (repeating the tests or doing different tests).

Government agencies such as NASA and Nuclear Regulatory Commission are counted on to provide higher levels of review, and rare disagreements among agencies are covered in Science and Nature, two top general journals. Even higher levels of review are provided by National Academy of Sciences, International Atomic Energy Agency, Intergovernmental Panel on Climate Change, and the like. And they are subject to complaints from the science community published in magazines like Science. Scientists devoted pages to finding every error in a 900-page report from IPCC, including the use of one “very likely” instead of the more accurate “likely”. Especially at the highest level, but often from the first article, scientists routinely make clear what is known, and how well, what is not known, and promising paths to expand on or challenge the thinking.

Yale Forum on Climate Change posted an analysis of all English-language climate contrarian books published through 2010, 108 in all. Their points about zombie arguments (arguments that don’t die no matter that they are refuted), unqualified authors and such apply to a number of discussions about the solutions to climate change as well.

When we bring up scientific ideas in discussions, consider where they fit in this continuum.

Scientists find it more difficult to communicate with the public than among themselves for obvious reasons. The subject is hard, and some words have very different meanings in science and the public discourse. Eg, “uncertainty” in science refers to a range of estimates, and “positive feedback” is not good. (See the table in Physics Today and the excellent source Climate Communication.) Or when International Energy Agency says that keeping temperature increases below 2°C is extremely challenging, what does the public hear?

In addition to the inherent conservatism of scientists, who don’t want to say what they don’t actually know, scientists in general, and IPCC in particular, almost always err on the side of “no drama”, as Naomi Oreskes has pointed out. This “no drama” approach has led to scientific estimates of the rate of climate change over the last couple of decades that more often underestimates, rather than overestimates, the rate of change.

“But Scientists Are Always Changing Their Minds!”

Isaac Asimov received a letter from a non-scientist explaining that scientists often think they get things right, but succeeding centuries show them they were wrong. His response, “The basic trouble, you see, is that people think that "right" and "wrong" are absolute; that everything that isn't perfectly and completely right is totally and equally wrong.” Instead scientists see knowledge as being refined. Asimov’s example is Earth shifting from flat to a sphere (350 BCE) to not quite a sphere because it rotated (Newton) to… , while the non-scientist described a process by which Earth is a sphere this century and a doughnut next.

“What actually happens is that once scientists get hold of a good concept they gradually refine and extend it with greater and greater subtlety as their instruments of measurement improve. Theories are not so much wrong as incomplete.

“This can be pointed out in many cases other than just the shape of the earth. Even when a new theory seems to represent a revolution, it usually arises out of small refinements. If something more than a small refinement were needed, then the old theory would never have endured.”