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Editorial: Taking a pop at Popper: Should Karl Popper’s education assignment have been failed?

I recently read about the thesis that Sir Karl Popper presented in order to qualify to teach in secondary school (Gattei, 2009). Karl Popper was a school teacher for a while (he qualified first as an elementary teacher, and later as a secondary teacher of physics and maths), and so he did what we could consider the equivalent of the PGCE (Post-Graduate Certificate in Education) course that was required in early 20th Century Vienna. 

He became a world famous philosopher - some say the most influential of the 20th Century.  Popper is particularly known for his work in two areas, although he probably would have seen all his scholarship as addressing a continuous programme of research. Popper first became famous for his work in the philosophy of science, but then later was even more widely known for writing about political topics - former UK Prime Minister Margaret Thatcher (also someone known for shifting from science to politics during her career) is said to have considered him her favourite philosopher, although I am not sure whether he would have especially valued that endorsement.

Popper’s thinking about science, and society

Popper came to fame after writing the classic work Logik der Forschung, known in the English version as The Logic of Scientific Discovery (1934/1959) followed-up by other works such Objective Knowledge (1979) and Conjectures and Refutations (1989).These works contributed to the general adoption of a view of science that moved away from the assumption that science could somehow produce absolute general truths, to a view that scientific knowledge is always provisional and open to further testing (an approach sometimes referred to as falsificationism). 

However, Popper is probably even more widely known for later works such as The Poverty of Historicism (1957/2002) and, especially, The Open Society and its Enemies (1945/2011). In that book Popper offers detailed analyses, in particular, of three earlier philosophers: Plato, Hegel, and Marx. Popper clearly has very little time for Hegel (who is not a household name today, but was a highly influential thinker at the time Popper was writing). Popper, just as clearly, has a great admiration for Plato, even though he is very critical of those aspects of Plato’s political philosophy (i.e., in The Republic) which might be considered totalitarian and, indeed, racist. Plato tends to be a dictator, albeit an intending benevolent dictator (but do not all dictators claim what they do is for the good of the people; the health of the Volk; the advancement of the nation; the safeguarding of the revolution?)

Perhaps most surprisingly from Thatcher’s favourite philosopher, is Popper’s praise for Marx, even if this did not protect his work from Popper’s critique. Popper clearly appreciated Marx as a scholar and thinker (although Popper did become more critical of Marx after completing the manuscript). 

What is wrong with social experiments?

Popper argues very strongly that untested large scale social experiments are very dangerous. They are based on ideological theories which are not sufficiently supported by empirical evidence - so suddenly changing the structure of a society to meet some ideal notion of a better state will almost certainly have unforeseen circumstances and therefore much potential to go wrong.  (We might think of The Terror in France, or the terrible cost in human lives due to starvation associated with the different communist systems introduced in the Soviet Union and P. R. China.) 

To consider a less extreme, but still telling, example, the 1944 Education Act in England ensured free secondary education for all (surely a good), but attempted to provide different kinds of schools for different kinds of pupils: something that can be caricatured as based on an ideological assumption that different children are inherently destined to be professionals, or craftsmen, or only capable of menial tasks under supervision. Therefore this initiative which can be considered part of the construction of a socialist welfare state (alongside the National Health Service, old-age pensions, statutory sick pay, unemployment benefit, etc.) initialled a national system of testing that determined which children went to which schools (except where parents were wealthy enough to buy their children places at independent schools), and so which got to the minority of schools offering formal qualifications of the kind needed to enter higher education. Unintentionally this system insidiously reinforced social differences by categorising scholarly potential and economic worth of people based on what they had demonstrated by age eleven, without taking into account how much of this was due to the differential educational resources available to children in different circumstances.

Rejecting major dictated shifts in society, Popper argued instead for a social engineering approach through implementing small, modest, changes; and then evaluating their effects; and, only then, deciding on the next step. So, what is needed is evolution, rather than revolution. Some readers will recognise a strong analogy with the use of action research in the classroom (McNiff, 1992), or other iterative educational research approaches such as design-based research (Reeves, Herrington, & Oliver, 2005) or lesson study (Allen, Donham, & Tanner, 2004). Classrooms, like societies, are complex social phenomena, where there are a great many factors at work - often interacting in unpredictable ways - many of which cannot readily be measured, and some of which may not even be recognised. Sometimes, making things better requires patience, and a ‘softly-softly’ approach.  

Popper’s shift from academic philosophy of science to political thought, and his attack on historicism - the tendency to see history as being similar to sciences such as physics and chemistry, and looking for some inherent law of progress which suggests a pre-determined human destiny - can be understood as in part influenced by his experience of being exiled from his homeland, Austria, during the Nazi regime. However, Popper had always been interested in the ‘demarcation’ question: what counts as a science?

For Popper, an idea is scientific if the person proposing the idea also proposes tests that could reasonably refute it, if it is wrong. The bolder the conjecture (that is, the more it seems the idea is likely to fail the tests) the better! Ideology, by contrast, tends to be metaphysical in nature - it is assumed ahead of collecting empirical facts. The Nazis were not open to considering they were wrong about the superiority of the Aryan ‘race’ and so looking to test the idea. The Soviet Union politburo did not consider Leninism a working hypotheses to be rigorously examined, but more of a creed. When events do not meet expectations, we do not abandon our ideology, but seek a rationalisation to explain events that is consistent with our beliefs - and this may even involve finding a scapegoat to blame for what has gone wrong. By contrast, a scientific approach is supposed to actively seek negative evidence and alternative explanations, and to consider all knowledge provisional and open to further examination.

What is wrong with educational experiments?

Some people strongly associate scientific research with experiments, but a scientific approach to enquiry means adopting the most suitable approach to a particular problem (National Research Council Committee on Scientific Principles for Educational Research, 2002), and the experimental method requires certain assumptions and conditions that may not be relevant to educational contexts. When an experiment cannot be undertaken rigorously, another strategy that fits better is a more scientific approach than simply doing a bad experiment.

The experimental method requires identification and control of variables, comparable (indeed, where possible, identical) samples exposed to different conditions, and the ‘subjects’ of the experiment not behaving any differently than usual just because they are being observed and measured. This is seldom possible in classroom teaching, which is why so many of the experiments carried out in education are bad experiments, and so poor research (Taber, 2019).  

Would Popper fail to qualify as a school teacher today?

As I mentioned at the beginning of this essay, I was reading about Popper’s assignment that he had to submit before he could qualify as a teacher - an assignment that in general terms might be considered to parallel the studies reported in this very journal. However, in some ways, this is an assignment that would not pass the requirements of the PGCE course here in Cambridge. PGCE students today undertake research related to better understanding their classroom context and/or improving their professional practice. Popper’s qualifying assignment was quite different:

The [assignment] deals with the problem of the impact of non-Euclidian geometries on two groups of problems … those concerning the foundations of geometry (questions having to do with the axiomatic development of geometrical theories, such as the problem of the independence and necessity of the axioms, of the completeness and consistency of axiomatic systems, as well as definitions should be explicit or implicit) and those concerning the truth and falsity of geometrical assumptions…” (translation offered in Gattei, 2009, p. 15)

It seems slightly bizarre, to us today, that someone seeking to qualify to teach should be allowed to present as their qualifying assignment a thesis on the foundations of geometry - even if they intended to teach mathematics. In the English system, especially in regard to secondary level teaching, the post-graduate route is founded on a (risky!) assumption that teacher candidates have a degree and therefore already know enough about their subject, and so now just need to learn how to teach it.

Developing subject knowledge for teaching

Learning about pedagogy is certainly an important theme for teacher education. There is little point a teacher knowing about a subject if s/he does not have the strategies and skills to effectively teach it to others. There is also an established literature around pedagogic content knowledge or PCK (Kind, 2009), which might be seen as a kind of second order domain of knowledge that relates subject knowledge and pedagogic knowledge (Taber, 2018) and encompasses such matters as the best educational sequence for resenting the concepts in a topic area to support learning, or common areas of student difficulty and misconception, or selecting the most fruitful examples to develop learners’ understandings of a concept.  

Engaging in the scholarship of teaching also actually supports an understanding of the subject matter - thus the old adage that you only ever really understand a topic when you can teach it to someone else (Taber, 2009). So, inevitably, teaching a class of children about Hamlet, or thermodynamics, or glaciation, or Hinduism - and, more tellingly, preparing for, and responding to, their vast array of idiosyncratic questions (sometimes naive, sometimes insightful, but often left field and off beam) leads to developing a more nuanced, better integrated, understanding of the subject matter.

This is all widely recognised. There is however a subtlety different aspect of subject knowledge development, which is less discussed, and which can be labelled as subject knowledge for teaching:

effective teaching can modify the organisation of one’s subject knowledge. A teacher needs good canonical subject knowledge, but [that] is not enough. A good teacher needs to think about the subject matter in ways that best support teaching for student learning (Taber, 2020, p. 5)

So it is useful for teachers to use the PCK they acquire to think anew about the subject matter itself - to interrogate it not just in terms of the logical structure of the discipline (be that mathematics, history, or whatever - the axiomatic basis of geometry, say), but in terms of how it is best conceptualised to support teaching it to students at a particular stage of their learning journey. 

So although we might approve of young Karl’s commitment to thinking about the fundamental nature of geometry as an aspect of his subject knowledge, we might also think that he would have been better advised to explore the geometry in the school curriculum in terms of how it is most productively understood to support teaching and learning. Or, we might wonder whether Karl was always better suited to be a philosopher than a classroom teacher. Even if that suggestion reeks of hindsight, Popper certainly reminds us that teachers are not second class citizens when it come to scholarship and research: likely there are many in the teaching profession who could have built great academic careers like Popper, but actually preferred, and got more satisfaction from, applying their own intellectual skills to the work of developing the thinking and understanding of others.

Those who do make great breakthroughs in scholarship in an academic field may be rightly lauded, but without those who supported them on their educational journeys, and those who teach others about their work as it becomes part of our shared intellectual heritage, there would be little value in the work of great thinkers - it would literally only be of ‘academic interest’. After all, all good teachers need to be philosophers in a sense, for example in developing heir own subject knowledge for teaching, but not all philosophers make good classroom teachers.

Acknowledgement. I owe the title ‘taking a pop at Popper’ to my late wife Philippa who suggested I write something under this heading many years ago. I finally have.

Keith S. Taber, Cambridge, 2020


Allen, D., Donham, R., & Tanner, K. (2004). Approaches to Biology Teaching and Learning: Lesson Study—Building Communities of Learning Among Educators. Cell Biology Education, 3, 1–7. 

Gattei, S. (2009). Karl Popper's Philosophy of Science. Rationality without foundations. New York: Routledge.

Kind, V. (2009). Pedagogical content knowledge in science education: perspectives and potential for progress. Studies in Science Education, 45(2), 169-204. doi:10.1080/03057260903142285

McNiff, J. (1992). Action Research: Principles and practice. London: Routledge.

National Research Council Committee on Scientific Principles for Educational Research. (2002). Scientific Research in Education. Washington DC: National Academies Press.

Popper, K. (1957/2002). The Poverty of Historicism (Abingdon, Oxon.): Routledge.

Popper, K. R. (1934/1959). The Logic of Scientific Discovery. London: Hutchinson.

Popper, K. R. (1945/2011). The Open Society and Its Enemies. London: Routledge.

Popper, K. R. (1979). Objective Knowledge: An evolutionary approach (Revised ed.). Oxford: Oxford University Press.

Popper, K. R. (1989). Conjectures and Refutations: The growth of scientific knowledge, (5th ed.). London: Routledge.

Reeves, T. C., Herrington, J., & Oliver, R. (2005). Design Research: A Socially Responsible Approach to Instructional Technology Research in Higher Education. Journal of Computing in Higher Education, 16(2), 97-116. 

Taber, K. S. (2009). Learning from experience and teaching by example: reflecting upon personal learning experience to inform teaching practice. Journal of Cambridge Studies, 4(1), 82-91. 

Taber, K. S. (2018). Masterclass in Science Education: Transforming teaching and learning. London: Bloomsbury.

Taber, K. S. (2019). Experimental research into teaching innovations: responding to methodological and ethical challenges. Studies in Science Education, 55(1), 69-119. doi:10.1080/03057267.2019.1658058

Taber, K. S. (2020). Foundations for Teaching Chemistry: Chemical knowledge for teaching. Abingdon, Oxon.: Routledge.