Summary of Popper’s lectures at the LSE

For many years Popper delivered a series of 15 lectures as an introduction to the philosophy of science. They were designed for undergraduates but many other people attended.

While Popper was alive Mark Notturno started work on a reconstruction of the lectures based on transcripts of tape recordings.  Work stopped with 12 of the 15 completed.

When I look at the unsatisfactory books on the philosophy of science, I often wonder what a good book would look like. What would I write myself?  Of course Popper was not writing a book, he lectured without notes and the theme of each lecture was the same each year but he talked about what was on his mind at the time.

  1. Values

Welcome to the lecture. Do not expect too much because I am a very bad lecturer and the important part of learning is what you do yourself. Be free to interrupt and to criticize.

Degrees of understanding and levels of criticism.

The distinction between tentative criticism and serious criticism that is based on good understanding of the issue (but understanding can always be improved).

The wrong reason to go to university, to learn to speak impressively.

The proper reason is to find out how little we can ever know.

The overwhelming importance of simplicity and clarity.

We should try to educate people to tell the difference between a charlatan and an expert.

Confusing clarity with precision. Clarity and simplicity are ends in themselves but precision is context-dependent.

Second point for the day, on fast and slow reading. Not enough people recognize the difference between skimming and reading. And the first part of scientific method is the method of reading a book.

Don’t believe me, but do try to understand me and be prepared to argue, to criticize me and force me to clarify my views.

2. Scientific Method

No such thing. On the non-existence of subjects (just problems) and no such thing as a “scientific method” that can reliably deliver the goods. Demonstrated by Planck, a great scientist with only one great discovery, and Einstein failed to achieve his next great break for 40 years after his initial achievements.

The Webbs (founders of the London School of Economics), Mill and the idea that we start by collecting material.

Observe!  Observe what?

First thesis, science starts from problems, not from observations.

The problem with textbooks, lack of historical background and context.

The mythical origin of geometry – measuring fields on the Nile

Plato’s cosmology and the disaster of Euclid’s textbook, regarded as an authority rather than a report on work in progress at the time.

Revealing Popper’s secrets, the four-step schema.

Problem -> Tentative Solutions -> Error Elimination by Criticism and Testing -> New Problems

  1. Problems

Repeating the basic message of the course – starting with problems.

Finding problems: known problems, problems that you find, the problem of starting with problems that are too hard.

Solving a problem should create more problems.

How to find solutions? No recipe (see Planck and Einstein above).

The historical approach (among others) but what about finding good ideas?

Still no recipe, just have ideas and criticize them.

The search for ideas by observation and the bucket theory of the mind.

Exams as a dipstick to find the level of knowledge in the brain.

Inborn knowledge, expectations and the active role of trial and error.

Preliminary criticism of induction, inductivism and the sunrise, refuted millennia ago by the discovery of the land of the midnight sun!

The resort to probability in place of certainty to prop up induction.

Inductivists like Carnap die frustrated but still calling for more work…

4. Diarrhesis

Why he does not believe in definitions.

How diarrhesis is different from the usual obsession with definitions.

He challenges the idea that useful discussion has to start with shared assumptions or presuppositions.

He argues that the more disagreement on assumptions, the better, citing 5th century BC Greeks vs Egyptians and other eastern cultures.

The corrosive effect of Marxism and Mannheim’s sociology of knowledge.

Culture clash and the piecemeal elimination of prejudices.

Aristotle, essences and the origin of the obsession with definitions (with reference to the handbook on good driving by the Commissioner of the Metropolitan Police).

The alternative approach, clarification, which he calls diarrhesis.

Two points, diarrhesis is only used when necessary and it is used for clarity, not precision.

The myth of the framework, people who stop learning, who think they have nothing to learn from people who have conflicting opinions.

5. Understanding

Breaking out of frameworks.

Killing bad ideas before they kill us.

Understanding and the four-stage problem-solving schema.

Start with problems rather than theories because the theory cannot be understood apart from the problem and this raises the question of understanding.

There is a school in social science which sees understanding as the unique feature of the social sciences.

Some quantum physicists deny that you can ever really understand.

The danger of teaching maths and science with no history of the problem situation – hence no real understanding.

The discovery of spectral lines in 1913 created the need for a statistical theory to account for probabilistic events at the quantum level: the need cannot be understood without a grasp of the evolving problem situation.

How do we understand the problem? By trying (and failing) to solve it.

The importance of making many mistakes in order to understand better.

The role of education to permit people to identify charlatans from experts .

The importance of serious testing and the history of science as refutations which created new problems and hence new science.

6. Cosmology

The lead up to Newton’s theory shows how science advances by the criticism and refutation of theories to explain the origin and structure of the universe (cosmologies and cosmogonies).

Our success in science is amazing considering how close we are to the ants and how far they are from having science and understanding of their situation.

Myths are the starting point, like the Maori myth of NZ being pulled out of the sea by a fisherman.

The first problem of critical (scientific) cosmology was to account for the stability of the fixed stars and the eccentric movements of some others, the wanderers, the planets.

The concentric crystal spheres led to the Ptolomaic system, then the heliocentric suggestion of Copernicus, then the equations of Kepler.

In the neo-Platonic religious background light had great significance: for cosmology that put the sun in the centre: for religion it meant letting light (God) into the churches, hence the gothic design with big windows replacing the Norman and Roman designs.

The geocentric and the heliocentric theories are completely equivalent with regard to observation.

What is wrong with armchairs for scientists?

7. Explanation

Science was inspired by curiosity and explanation can be seen as the historical aim of science.

Explanation is always deductive.

Other views on the aim of science – prediction and practical application (the American pragmatists).

The logic of deductive explanation from the explicans (the cause) which consists of a universal law plus initial conditions, to the explicandum (what was to be explained).

Explanations can be circular or ad hoc and science advanced as the demand for non-circular explanations became more strict.

Better ideas about explanation emerged to avoid charges of circularity and ad hoc explanations.

Aristotle founded the essentialist school of explanation, using “essences” which are supposed to represent the rock bottom of explanation, leaving no more questions.

Modern opponents of essentialism are usually instrumentalists or pragmatists.

Instrumentalists nowadays defend science but originally instrumentalism was a weapon used by the Church against science (Cardinal Bellarmino vs Giadorno Bruno and Galileo) against science! Similarly Berkeley used instrumentalism to criticize Newton’s science and also the calculus.

According to modern instrumentalists we make theories for prediction, in contrast, according to Popper we make predictions to test our theories.

8. Scientific Knowledge

Science begins and ends with problems.

P -> TS -> EE -> New P

This runs contrary to the expectation that science should end with less problems and more knowledge.

For standard epistemology real knowledge means justified true beliefs, that is knowledge which is (a) true and (b) which we have sufficient reasons to believe to be true.

Scientific knowledge never satisfies the most severe conditions and so we never know for certain, and we never know how long may be required to find that it is false.

Scientific knowledge has no authority, even though it is the best knowledge that we have.

The quest for authority became a quest for sources or criteria of truth, for knowledge with a pedigree.

Historically, there came a great desire to escape from dogmatism and rely on something other than Aristotle, instead to rely on senses and reason, however these became authorities in their turn.

Popper is in favour of reason and also in favour of evidence from the senses but neither can be regarded as authorities.

He is not concerned with sources or pedigrees. Science begins when a theory is presented for discussion and criticism.

He is happy for scientists to disagree, for problems to be open and the contest between theories to be undecided.

It is not a healthy situation where scientists are unanimous, that is most likely due to lack of imagination and criticism to generate new problems and rival theories.

In contrast Kuhn regards unanimity (the shared paradigm) as healthy and normal.

Science is revolution in permanence and criticism is the lifeblood of science.

9. Truth

Criticism or error elimination in the four-step schema is an attempt to eliminate what is false to strive to arrive at the truth.

Omniscience is not a practical aim of science, instead truth should be regarded as a REGULATIVE PRINCIPLE (following Kant).

Given the model of proof from maths and logic, epistemologists have been very keen to find a proof for the truth of scientific theories.

That led the search for a CRITERION – Descartes (clear and distinct ideas), Bacon (clarity and directness of perception).

The over-optimistic “manifest theory” of truth and its counterpart, the conspiracy theory of error. Failures of criterion theories of truth led to relativism, the corrosive form of skepticism – there is no such thing as truth.

Between the optimists and the pessimists, the pragmatists sought a middle ground in the success of theories.

Two other “middle ways” between optimism and pessimism, the COHERENCE and CONVENTION theories of truth.

Viennese efforts to get clear on various correspondence theories – Schlick and Wittgenstein.

Tarski’s solution, and the rehabilitation of the correspondence theory, using modern logic, to maintain the regulative idea of truth.

10. Falsity

More discussion of truth, Tarski and metalanguages.

The law of the excluded middle: unambiguously formulated statements are either true or false, no middle ground (proved by Tarski).

This is signaled as a preliminary statement in advance of the discussion of theories in economics and the social sciences in the next lecture, where we have to operate with theories that we know are false.

Same applies in astronomy where all our models are over-simplifications; the sun and planets treated as “masspoints”; the sun is not really an ellipsoid (it has craters and bulges); light exerts pressure on planets which is practically always neglected in calculations.

Reality is too rich to depict in a model, we abstract and select according to our problem and purpose at the time, and according to our theoretical knowledge at the time.

Our picture of the world is always defective, always false and over-simplified and always contains real mistakes in addition to the over-simplifications.

11. Social Science

A story: a critic of Popper’s views on Plato first stated that Popper was wrong to identify Plato as a forerunner of totalitarianism, then later he wrote that Plato was indeed a forerunner of totalitarianism and Popper’s criticism was misguided because totalitarianism is inevitable due to its strength and efficiency. Between the two criticisms the Russians launched sputnik into space, which triggered something like hysteria in the free world with a panic about the state of western education and science.

Speculations on things that could kill science: too much money, the publication explosion (good buried under bad), angling for money at the expense of good science, hostility of the mediocre to the producers because the unproductive fear they will miss out on the big money.

Hopeful signs (in those days of the 1950s) that many students and scientists were still more interested in learning than money.

Serious concern about the split in the social scientists between factfinders and theoreticians. The factfinders were dominant and made fun of the theorists but they had no theories worth testing and many became part of the advertising industry.

Moving on to the methods of the social sciences, first of all, is there a difference from the natural sciences, perhaps due to the “Oedipus effect” of predictions which become self-fulfilling?

He found that a similar effect could occur in the natural sciences using calculating machines.

He rejected the idea that the natural sciences are intrinsically more objective, the rationality of science depends on the free exchange of criticism (and is undermined when that is reduced).

“Objectivity consists in the clash of biases, not their elimination”.

Beware of anything that appears to be intuitively self-evident.

Another story: a scientist was investigating why the leaves of a plant twist to the left in New Zealand as opposed to the right in England. After working for a year on the problem he attended a Popper lecture, then he checked and found they twisted to the right. No problem!

Bacon on “confirmation bias”, seeing what our theories (prejudices) tell us to find. Bacon’s solution was the empty mind (no assumptions), Popper’s solution is to subject all assumptions to critical analysis, use observations as criticisms, not confirmations.

On the differences between natural and social sciences, for the most part the difference are not what people think they are, but there is a difference, and that is the use of the rationality principle.

12. The Rationality Principle (RP)

Hume, Rousseau and Freud on human irrationality.

Freud as a rationalist: we act rationally within the limits of our knowledge at the time AND understanding the cause of neurosis should result in a cure.

Popper’s rationality principle means explaining actions in terms of the situation (situational analysis).

Not a hypothesis to be tested, but a principle of method (a “rule of the game” of social science):

The rule: Try to explain things rationally.

The RP is the functional equivalent of a law of nature in a deductive explanation which starts with a situation (laws and initial conditions, the situation) and produces an effect, the action.

The RP “animates” the model that we make to explain the actions that generate social phenomena of all kinds (war, inflation, unemployment etc).

We know it is false because it is over-simplified, abstracted from the full complexity of the world, like our models and theories in the natural sciences.

The RP should not be confused with personal rationality which is the willingness to correct our ideas.

The RP is a principle of explanation and a heuristic, a guide on what to look for in social situations.

The next major point in the lecture is the nature and function of institutions – social, political, cultural.

Study of institutions raises all the most interesting and important questions in the social sciences. Among the institutions are traditions.

Traditions have an almost biological basis.

The various ways we learn – trial and error, imitation, systematic research.


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2 Responses to Summary of Popper’s lectures at the LSE

  1. Zoltan Sostai says:

    Are the full transcripts of these lectures available somewhere?

  2. Rafe says:

    Unfortunately they are not Zoltan, but two are on line here

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