Karl Popper vs. Thomas Kuhn — Jed Lea
Jed Lea-Henry
In conversation with Steve Fuller   &nbsp;  In 1935 a former-peasant farmer, Trofim Lysenko, was out to change the face of Soviet agriculture. Decades of clawing his way towards political power were paying off, and there he finally stood delivering a speech to a full session of the Politburo. An
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Jed Lea-Henry
In conversation with Steve Fuller

In 1935 a former-peasant farmer, Trofim Lysenko, was out to change the face of Soviet agriculture. Decades of clawing his way towards political power were paying off, and there he finally stood delivering a speech to a full session of the Politburo. And he had a theory about how to grow a higher yielding wheat.

The theory originally belonged to French zoologist Jean-Baptiste Lamarck, who believed that the traits acquired by one generation of an organism could be passed-on and inherited by the next. In the hands of Lysenko – as he looked-out from behind that lectern – it was transformed into Marxist Genetics. A theory that not only promised to radically transform the farming landscape, but which had the added benefit of being ideologically attractive to his fellow communists (seen as a way to breakdown peasant opposition by directly engaging them in an “agricultural revolution”).

The years of terror and purges and gulags were building momentum, and Lysenko seized the opportunity. He loudly attacked his critics in the audience, and across the Soviet Union, as being enemies of the revolution and against Marxist-Leninism. As he wound-down a single voice called back at him from the hall, “Bravo, Comrade Lysenko, Bravo.” It was Stalin!

By 1940 Lysenko was the director of the Institute of Genetics at the Soviet Academy of Sciences, and his detractors were either in prison or dead. The data was increasingly catching-up with Lysenko's extravagant claims, but with his model then being taught as “the only correct theory”, nearly every geneticist and biologist in the country was playing an understandable game of duplicity; falling over themselves to offer public support, while denouncing anyone not doing so with enough vigour.

Through failure after failure, Lysenkoism continued as state policy, with millions dying in famines across the Soviet Union. Even then it was still exported to Maoist China as a success story, where it contributed to the policies of the Great Leap Forward and another forty million deaths.

Just how you see and understand the mistakes here, will also define your sympathies with the greatest ever split in the philosophy of science!

For Thomas Kuhn, Lysenko’s blunder involved believing in an immature theory, one that wasn’t established within an existing paradigm. For Karl Popper, the problem was Lysenko’s inability to acknowledge the errors that were happening all around him, and accept that his theory had been falsified. At first glance it may not seem like that rich of a debate, both men were, after all, in agreement that Lysenko was wrong; they just had different reasons for thinking it. But this was no minor disagreement in the parochial corners of academia. The Popper vs. Kuhn debate shook the ground of epistemology as well as popular imagination and public attention. It was nothing less than “the struggle for the soul of science”.

The two men couldn’t have been more different. Kuhn started his career as a physicist, whose academic transition was forced upon him by colleagues who considered his research “too philosophical”. Despite his reputation as a radical theorist, Kuhn preferred to keep his own counsel, avoiding comments on the nature of contemporary science as well as the political climate unfolding around him. As Steve Fuller notes, ask anyone about Kuhn and “usually the response is positive, even enthusiastic”.

Popper by contrast began his academic life as a child psychologist, and came of age thinking about social progress and the role of science within it. Developing a reputation as a “grumpy autocrat”, he “thundered against virtually every dominant tendency in the physical, biological and social sciences.” A man who “rarely received the recognition he thought he deserved – and never tired of reminding everyone of it”… odd behaviour for someone who received a knighthood long before his retirement years.

Reputations aside, timing was also a factor here. Popper’s seminal work, The Logic of Scientific Discovery, was first published in 1934 in German. Never one to avoid the spotlight when offered, Popper spoke and lectured and argued and wrote and published constant addendums and clarifications as the decades went by. So known more by his “reputation than by readership”, when The Logic of Scientific Discovery was finally translated into English in 1959, the public response was muted, even “bemused”. Sure, they might not have already scrolled through its pages… but in another way, they had!

Everything that Popper wished for himself, fell neatly into Kuhn’s lap. The Structure of Scientific Revolutions is an expanded version of an encyclopaedia entry: sparsely referenced and written in non-technical language, the thirteen short chapters explain in simple detail how science has changed and what its phases are. Ending-up at just a little over 200 pages, it is also uncharacteristically short. And yet, again in the words of Fuller, it “was the most influential book on the nature of science in the second half of the 20th century – and arguably, the entire 20th century.”

For Kuhn science looks a little friendlier and a little less grand than Popper would have it. Everything begins with a paradigm, a slice of research that is considered so outstanding that it is adopted by the broader scientific community. This research provides a blueprint for future research, and this subsequently happens. Most scientists follow the pattern and the prevailing standards, tinkering in the lab to improve the technical details of the paradigm. This behaviour is what Kuhn calls normal science. Not trying to break new ground, not trying to change the world, but simply solving minor puzzles within a larger, unquestioned, theory.

But soon, something else bubbles to the surface. Not all of those puzzles are solved, and over time they accumulate one-upon-the-other, until a point of crisis is reached. It is only here, as a last desperate and unwelcome moment in the life cycle of science, that things fracture, people begin to ask difficult questions about the future direction of their research, and an irreversible revolution occurs. The changeover happens quickly, a new paradigm is agreed upon, and everyone happily moves back to the practice of normal science.

Kuhn’s understanding comes from a deep look into the history of science, and how it truly looks on the ground. Popper thought differently, and lamented as to why on earth someone would talk this way, why someone would try to extract prescriptive lessons from the history of science and encourage young minds to continue like this when, in his view, very few people had ever been any good at actually doing science.

For Popper the “core scientific ethic” was falsifiability – all knowledge, at all times, should be exposed to constant and deliberate criticism. It comes down to the problem of epistemology – that perpetual question of how knowledge forms. What all latter-century philosophers – including Kuhn – owed to Popper was his solution to this problem. Famously it was that of conjecture and refutation: we guess at truth, and then criticise those guesses. The theories that survive this are still never accepted as true, only not rejected as false. And if this is how we make progress, then the same must also fit for science.

So, for Popper, someone is being scientific only when they are aggressively testing the limits of existing science. There is no place in this picture for protective paradigms, and certainly none for the type of work that happens within those paradigms: trying to prove a theory correct (a harmful and impossible exercise) and trying to shield it from falsifiability.

Kuhn’s response was simple: he could see the value in what Popper was saying, but as he scoured the annals of history, he found very little evidence of falsifiability working away as a key ethic in science. Popper’s response to this was also simple: exactly!

But Kuhn did have a point here, he noticed something that many others would later also do. Something that Popper seemed a lot less tuned-in to. “Criticism is productive” writes Steve Fuller, “but only under certain conditions”. It is easy to see why in the very early stages of research that harsh and piercing criticism might not be all that useful. Better to wait, if only a little, until the person in question has a clearer understanding of their own theory, and the predictions that it makes. This is a line that Imre Lakatos tried to splice between both Popper and Kuhn, bridging the difference between them in some ways.

From early disagreements, the fight here gets personal, fast. There were two versions of history according to Popper, one in the legacy of Socrates and the other in the legacy of Plato. The Socratic version imagines progress struggling forward through a dialectic of trial and error and then failure, followed by more trial and error. And hopefully this brings us closer to where we want to be. The Platonic version is indifferent, it says that no matter what we do the outcome will always be the same. Already known for his short temper, this is where Popper starts to get really angry.

To be mistaken is the common state of things, we are always wrong in some way, but for Popper this Platonic vision was much more than that, it was historicism (the idea that history is completely determined by certain laws, and so the future can be accurately predicted by understanding those laws). Refusing to admit error is different to just making errors – it means that we never change course or accept our faults. We continue as we are, because it is all out of our control anyway. Popper saw the analogues of this type of thinking all around him, in the worst crimes and most oppressive tyrannies that the world had to offer.

Historicism was not just wrong, but immoral – and insofar as Popper and his followers saw historicism hugged-tight within the concept of normal science, Kuhn was also immoral.

As philosophical disagreements go, this one was excruciatingly personal. After reading through Kuhn’s arguments for the first time, Paul Feyerabend – then still a key disciple of Popper – called it nothing more than “ideology covered up as history”. Another person deep within Popper’s circle, John Watkins put it like this: “Kuhn sees the scientific community on the analogy of a religious community and sees science as the scientist’s religion.”

It looks the same from different angles, and comes down to a question of emphasis and language. The word Kuhn used to describe that pivotal moment in science, when everything was on the cliff edge of great change, was crisis. And it seemed much more than an aesthetic choice. Kuhn didn’t have the taste for upheaval and insecurity, nor debate and criticism. So when this happened in science, it was also unpleasant – a moment of “confusion and despair… a spiritual catastrophe”. That such catastrophes were also when science jumped forward and when rapid progress happened, was beside the point. It certainly wasn’t enough to make him embrace a Popperian type of permanent revolution. Instead Kuhn made an unimpressive choice, and elevated normal science over extraordinary science.

Life inside a Kuhnian paradigm stretches the religiosity a little further still. Here the community of researchers create science in their own image: setting the standards, recruiting people who will continue with those standards, and then hovering as divine judgement over how well they go about doing this. It is a mini-Vatican, a state unto itself where the only safeguards are those which they create. If you don’t like the religious analogy, then Fuller has a couple of others that fit: a “royal dynasty” or “the Mafia”. It is a horribly circular world, where no-one is ever accountable to anything, or anyone, outside of themselves: “a paradigm is simply an irrefutable theory that becomes the basis for an irreversible policy.”

It plays out in education as well, where perhaps Popper’s hope that students “learn to live with an unrelieved sense of insecurity” might seem a little questionable, but not when compared to Kuhn, who “reduced science education to an indoctrination strategy.” It also shows up in the details of what Kuhn considers to be his trump card: his own scholarship about the history of science. Across those famous pages are a few glaring omissions of fact. Kuhn chooses to end his study of chemistry for example way back in the 1850s, and also stops talking about physics after the 1920s. The reason for this? Fuller has an idea:

Given Kuhn’s exclusive interest in science as pure enquiry, it is reasonable to conclude that he believed that after those dates, those disciplines ceased to be relevant to his model.

There is still a purpose behind the madness here for Kuhn. He wanted something for science, something Popper also wanted: independence. And in a way normal science did this! Isolated within a self-enclosed paradigm, the field was protected from swings in policy and changes of government. Here scientists could get down to perfecting their craft without intrusions from the chaos and whims of the outside world.

This is certainly independence of a kind, but not the kind that Popper thought was important. Those high walls that Kuhn built around science unquestionably cleared a space where it could have autonomy, but it was only autonomy for the larger scientific community. What about the individual scientist? What about his ability to make his own decisions, even if that meant deciding that everyone else is wrong? Popper looked back at his colleague in obvious disbelief over this point, how could he not see the hypocrisy and the breakdown in his own values. Soon Popper would start calling Kuhn’s version of independence a “heads down approach” to science: a pejorative description that Kuhn would have seen as a complement.

More than just the damage it does to itself, a heads down approach to science comes at an unpleasant social and moral cost. To flesh this out Fuller makes an interesting analogy from the recent history of philosophy. Martin Heidegger was a hugely important figure in the 20th century whose work on phenomenology, hermeneutics, existentialism, and particularly his book Being and Time, is still taught in nearly every half-decent undergraduate philosophy course. He was also an unreformed, and unrepentant, Nazi.

It comes down to a question of social responsibility, and individual integrity. Kuhn’s moment of reckoning was the Cold War, and how his commitment to doing normal science played out over those years. At few prior times in history had the work of science and scientists ever reached such prominence, as well as national recognition. Yet however you might view the nuclear standoff and those terrifying decades, the important standard for most people was, and still is, that you act on, and speak about, what you believe to be true. Courage matters!

They can still be criticised for being wrong, but the people in Popper’s circle did just that – they took risks, they put their careers on the line in order to speak their minds. They upset a lot of people in positions of power: Imre Lakatos against the military industrial complex, Paul Feyerabend against government funding in science, and Popper himself against the Vietnam War.

Happy with his life in the lab, Kuhn did the opposite and kept conspicuously quiet… about nearly everything! He had his paradigm in place, his days were kept busy by normal science, and so he let the world outside float uncritically by. Even as his book, The Structure of Scientific Revolutions, was being used to justify the silencing of dissent and the control of science by government and the military. Rather than just letting cowardice overcome him, Kuhn saw this repression as a positive – a stabiliser behind which normal science could continue.

More than just a means to an end, it all sounds incredibly totalitarian, from top to bottom. And if nothing else, Kuhn surely had a responsibility to address the implications of his theory. Especially as they began to manifest in nuclear conflict. Feyerabend sums it up well:

The recipe [for a successful science], according to [Kuhn and his followers], is to restrict criticism, to reduce the number of comprehensive theories to one, and to create a normal science that has only this one theory as its paradigm. Students must be prevented from speculating along different lines and the more restless colleagues must be made to conform and ‘to do serious work’… Is it his intention to provide a historico-scientific justification for the ever growing need to identify with some group?

Over the years, Kuhn declined countless opportunities to speak publicly – to correct the record, to offer any sort of opinion – as well as opportunities to debate his academic colleagues; bringing Fuller to ask the necessary question: “Is Thomas Kuhn the American Heidegger?” But throughout his silence, there was one request he just couldn’t refuse, one instance that bucked the trend. In July 1965 Kuhn, then aged 43, turned up at Bedford College, University of London, for the International Colloquium in the Philosophy of Science. He had turned up to debate Karl Popper!

Organised by Imre Lakatos, it was delicately staged: the young vs. the old (Popper was 63 at the time), the authoritarian vs. the libertarian, the shy vs. the fiery. And yet, somehow, the rare importance of what they had before them was lost to the egos of the men involved. It began with Popper refusing to accept “equal billing with the upstart Kuhn.” After too much late night anger, he decided instead to chair the debate and leave the actual fighting to Lakatos and Feyerabend. Lakatos however saw this as an opportunity not to argue by proxy for his mentor, but to argue for himself and his middle-ground philosophy (between the extremes of Popper and Kuhn). And Feyerabend – “Popper’s most radical follower” – continued down that path, deciding to push his own branded philosophy (epistemological anarchism) to an audience that had come to listen to something else.

As it turned out, this came to little anyway, because both men, inexplicably, failed to finish their papers in time for the debate. Again things had to shift, and the hard Popperian lifting was assigned to Jagdish Hattiangadi. At which point it was Kuhn’s turn. His own sensibilities strained too far, and now flaring with white anger, he refused outright to share a stage with the younger man. So in near comic circumstances Hattiangadi’s advisor, John Watkins, literally picked up his student’s notes and delivered them on stage in his stead.

And that was it! The two greatest philosophers of science brought together for the most significant event ever staged – “a landmark in 20th century philosophy” – and it all ended in a soft and ignominious fizzle. In the aftermath you can almost see the figure of Thomas Kuhn on his slow and disappointing boat ride back to America. Staring out over the railings and into the sunset. Thinking aloud and struggling to make sense of what had just happened – the infighting, the childishness, the tardiness, the self-admiration, the lack of substance… And in that moment making a firm promise to himself never, ever, to do it again!