Realism and antirealism in secondary science education
Updated: Nov 8, 2019
The 'nature of science' has taken a back seat in science curricula with the GCSE reforms pushing for more emphasis on content, and less on skills, scientific literacy, and the methods of science. However, I think there is plenty of space to embed deep philosophical thinking into the new curricula, particularly in the realism vs antirealism debates.
At secondary level, the nature of science is generally thought to consist of the following ideas about scientific knowledge:
it is tentative;
it is empirically based;
it is subjective and/or theory laden;
it involves human inference, imagination, and creativity; and
it is socially and culturally embedded.
Furthermore, at secondary level, the nature of science is supposed to be sufficiently vague to be compatible with both realism and antirealism.
So what's scientific realism?
Basically scientific realism involves two key claims:
That the aim of science is to progress towards the 'truth', and our best scientific theories are at least approximately true.
That the theoretical terms, both observable and unobservable, that scientific theories refer to really exist.
This means that scientific realists think that our current theory of the atom is at least approximately true, and we know this because it is a very well confirmed theory. And also the scientific realist believes that atoms actually exist, and have the properties that our theories say they do.
This all sounds very reasonable, and I have a hunch that it probably rings true with most science teachers. I cannot count the number of times that I have walked through lessons and heard teachers saying things like, "it's really true".
And what antirealism then?
It turns out that realism is really difficult to defend. Antirealists attack realism on a number of key fronts. I have not included an exhaustive list, or attempted to defend any of the positions, but selected views which could form the basis for interesting conversation in a secondary science classroom.
Antirealists can deny that science aims at truth (because truths about science are unknowable), and say that science aims for empirical adequacy instead.
So, for example, we could say that we don't really know whether our best scientific theories are true, but we can know whether they work, by testing to see whether they give accurate predictions.
Newton's theory of gravity was empirically adequate, it explained people's observations and made accurate predictions. It has now been replaced by Einstein's theory of space-time which is more empirically adequate: it explains a greater range of observations and has made some wildly unpredictable predictions correctly. But (so says the antirealist) who are we to say that space-time is closer to the truth in the world-out-there?
Antirealists can deny that scientific theories are mind-independent, and say that they are subjective and/or socially constructed instead.
The full-blown version of this version of antirealism is a form of idealism which denies we can have any knowledge of the external world at all. But there are lots of softer versions of mind-independence too.
Firstly, different scientists, with different background knowledge, look at the same evidence, they might come to different conclusions. For example, the phlogiston adherent would have come to different conclusions to the oxygen believer from some of the same experiments.
And, secondly, science does not take place in a cultural vacuum: political views, the dominant religious and philosophical ideas, and the economy, all have a part to play in how scientific knowledge is constructed (often due to differences in funding provision) and interpreted (due to different background beliefs).
Antirealists can deny that theoretical terms refer to actual entities in the world, but are instruments for making our theories work in the observable domain.
This is similar to the first antirealist attack, but this suggests that we cannot know about any unobservable entities postulated by science, such as atoms, or, for some antirealists, anything that cannot be seen with the naked eye, such as cell structures or colourless gases.
Instead, according to the antirealist, postulating atoms, with the various properties we give them, helps to explain other observations we make, such as different flame colours, but that doesn't mean they exist. They are just a tool to make the maths work.
This form of antirealism has had many illustrious scientific proponents. In particular the Copenhagen interpretation of quantum mechanics, and its father Neils Bohr, is strongly associated with an antirealist outlook on the existence of unobservables in physics.
Antirealism in the classroom
Most of the time in secondary science classrooms, we offer a fairly robust realist position. And I think that's right: how can we expect students to design experiments to test how electrons travel through a circuit at different temperatures if they don't believe in electrons?
When students are learning conceptually challenging new theory, or carrying out complex problem-solving tasks (like scientific inquiry), it is time for realism. The last thing they need is layers of philosophy added on top. But there's still room to discuss some of the important questions that antirealism raises.
Here are some example questions to ask:
Is Newton's theory of motion true, approximately true, or does it not matter so long as it gives us the right predictions?
This makes quite a fun class discussion, with students working in small groups to come up with their ideas and reasons, then feeding back to the class. It doesn't need to take long, it's just good to give students a chance to realise that all of the positions can be defended.
If students start giving some really good ideas, then they could be asked to complete some extended writing arguing for a particular position for homework. (This occasional change of homework task to something which appears more effort-driven is a great way to make physics more gender neutral - see my blog for more.)
This could easily be applied to any new theories covered at GCSE, such as:
wave theory, and,
the big bang theory.
Why should people believe in atoms?
What I like about this one is that any answers students give can be given an antirealist response back. For example, a student might recall a picture of the surface of a metal taken from a scanning electron microscope earlier in the course, to which you can respond "do you think someone who doesn't believe in atoms will be convinced by a picture taken by electrons?" pushing students to think even more deeply.
This also works really well in biology for anything viewed under a microscope, as the antirealist can refuse to be convinced by how the microscope lenses affect light (and since we can't see the properties of light we postulate - either wave or photon - the antirealist has a strong position).
You can also ask students to order scientific entities, like the moon, far off planets, electrons, quarks, viruses, bacteria, acids, etc. into the order from most believable to least believable.
Probably best left until students are pretty convinced that atoms (or whatever you're using as an example) are real to avoid conceptual confusion later.
Deep thinking for deep learning
I would expect most students to leave school as scientific realists, but with some understanding of the tentativeness, subjectivity, and socially constructed nature of science. This is all facilitated by dialogue and debate on these questions.
But even more, in order to answer these kinds of questions, students need to express a deep understanding of the scientific content in a different perspective. Reformulating their knowledge of atoms into an argument about why we should believe in atoms, facilitates chunking of students' knowledge about atoms, deepening their content knowledge.
Given that there's a lot of content on the new GCSEs, we need to get the students thinking as much as possible, even if it means that we need to step out of our familiar 'realist' comfort zones to do it.