Black swans and other deviations: like evolution, all scientific theories are a work in progress

EPA, CC BY-SA

Discussions about the nature of science and scientific theories are often confused by the outdated view that such theories are rendered false when anomalies arise. The notion of a scientific theory as a static object should be replaced with the more current view that it is part of a living research programme, which can broaden its scope into new areas.

For example, take the hypothesis that all swans are white, which seemed pretty good to Europeans until Dutch explorers found black swans in Australia in 1636. So what happens to our hypothesis? There are a number of options.

1) Redefine swan-ness to include whiteness. Then black swans aren’t really swans, and the hypothesis remains true by definition.

2) It’s been disproved. Discard it.

3) Compare different species of swan the world over, and see how well black swans fit in.

(1) is the least useful. Definitions can only tell us about how we are using words. They tell us nothing about the world that those words attempt to describe. (2) is based on the common-sense idea that hypotheses should be discarded when falsified by observation. This was the idea put forward by philosopher Karl Popper in the 1930s, to distinguish between science and pseudoscience.

In praise of fallibility; why science needs philosophy, with examples from astronomy and chemistry

[Adapted from 3 Quarks Daily] More recent strata lie on top of older strata, except when they lie beneath them. Radiometric dates obtained by different methods always agree, except when they differ.  And the planets in their courses obey Newton’s laws of gravity and motion, except when they depart from them.

As Isaac Asimov reportedly said, “The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ [I have found it], but ‘That’s funny …’ ” And there is nothing that distinguishes so clearly between the scientific and the dogmatic mindset as the response to anomalies. For the dogmatist, the anomaly is a “gotcha”, proof that the theory under consideration is, quite simply, wrong. For the scientist, it is an opportunity. If an idea is generally useful, but occasionally breaks down, something unusual is going on and it’s worth finding out what. The dogmatist wants to see questions closed, where the scientist wants to keep them open. This is perhaps why the creationist denial of science can often be found among those professions that seek decision and closure, such as law and theology.

The rights and wrongs of falsification

Karl Popper (LSE Library photo, 1980s)

Dogmatists regularly invoke the name of Karl Popper, and the work he did in the 1930s. Popper placed heavy emphasis on falsifiability, denouncing as unscientific any doctrine that could not be falsified. Freud’s theories, for example,

The “scientific method”, a needless stumbling block. With a note on falsification

Science does not have a separate special method for learning about the world, the “scientific method” as taught in schools is a damaging illusion, and the falsifiability criterion has itself been falsified

Below, R: How not to; “The Scientific Method”, as inflicted on Science Fair participants. Click to enlarge

Consider this, from a justly esteemed chemistry text:

Scientists are always on the lookout for patterns.… Once they have detected patterns, scientists develop hypotheses… After formulating a hypotheses, scientists design further experiments [emphasis in original]

Or this, from a very recent post to a popular website:

The scientific method in a nutshell:
1. Ask a question
2. Do background research
3. Construct a hypothesis
4. Test your hypothesis by doing experiments
5. Analyze your data and draw conclusions
6. Communicate your results [emphasis in original]

Then, if you find yourself nodding in agreement, consider this:

Since a scientific theory, by definition, must be testable by repeatable observations and must be capable of being falsified if indeed it were false, a scientific theory can only attempt to explain processes and events that are presently occurring repeatedly within our observations. Theories about history, although interesting and often fruitful, are not scientific theories, even though they may be related to other theories which do fulfill the criteria of a scientific theory.

If you are familiar with the creation-evolution “controversy”, you may well suspect that last example of being so much creationist waffle, intended to discredit the whole of present-day geology and evolutionary biology. And you would be right. This quotation is from Duane Gish, a major figure in the twentieth century revival of biblical literalist creationism, writing for the Institute of Creation Research.¹

L: Mike Pence, ” [N]ow that we have recognised evolution as a theory… can we also consider teaching other theories of the origin of species?”

Such nonsense isn’t funny any more, if it ever was. The man who may very soon find himself President of the United States is an eloquent spokesman for creationism.

And yet Gish’s remarks seem to follow from the view of science put forward in the first two excerpts. What has gone wrong here? Practically everything.