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Popper Book Summary – Bryan Magee

What you will learn from reading Popper:

– Why only through criticism can knowledge advance.

– Why there is asymmetry between verification and falsification.

– Why being proved wrong is a sign of progress.

Popper Book Summary



The Importance of Criticism: All of Popper’s work reflects his belief which will be made fully clear later, that only through criticism can knowledge advance.

Why you should care about philosophy:

Karl Popper argues that philosophy is a crucial pursuit because we tend to take numerous assumptions for granted in all aspects of our lives, from personal to professional. While some of these assumptions may be accurate, many may be false or even harmful. Therefore, engaging in critical scrutiny of our presuppositions, which is a philosophical endeavour, is not only intellectually but also morally significant.

Popper views philosophy as a practical and essential part of everyone’s life, rather than an academic discipline or a specialised field, and not merely confined to studying the works of professional philosophers.

What this book is about:

This book is give a bold, clear outline of Popper’s thought which exhibits its systematic unity. This involves, for reasons which will become obvious, starting with the theory of knowledge and the philosophy of science.


2 – Scientific Method – the Traditional View and Popper’s View

What are laws of nature:

The term “law” can be ambiguous, and individuals who refer to a natural or scientific law being “broken” are conflating the two primary meanings of the word. A societal law prescribes what actions are permissible or impermissible, and it can be violated. In fact, it would be unnecessary to have a law if it could not be broken. For example, there is no legislation against a person being in two places at once.

In contrast, a law of nature is not prescriptive but descriptive. It explains what occurs, such as water boiling at 100°C. It is a statement of what happens given certain initial conditions, such as the presence of water and heat. It is neither true nor false but rather a description of a natural phenomenon that cannot be “broken” since it is not a command.

Today, it is widely accepted that natural laws are not directives that must be “obeyed” or “broken.” Instead, they are explanatory statements of a general nature that aim to be factual and must be adjusted or discarded if found to be inaccurate.

The formulation of science:

The scientific approach formulated by Francis Bacon has influenced individuals with scientific inclinations from the 17th century until the 20th century. It follows a particular sequence: the scientist initiates experiments with the intention of making precise and controlled observations on the boundary between what is known and unknown. The findings are meticulously recorded and published, and over time, a shared and reliable dataset accumulates.

From this data, general characteristics begin to emerge, leading researchers to form hypotheses that explain the causal relationships between known facts in a law-like manner. The scientist then seeks evidence to support their hypothesis, and if it is confirmed, a new scientific law is discovered, unlocking further insights into nature. The discovery is applied in all relevant areas to gain new information, adding to the existing stock of scientific knowledge and pushing the frontier of our ignorance.

The problem of this scientific method – induction:

The scientific method, which involves making general statements based on accumulated observations of specific instances, is commonly referred to as induction and is regarded as the defining characteristic of science. Scientific statements are distinguished from other types of statements because they are based on empirical evidence, i.e., observations and experiments, and are therefore deemed to provide reliable and certain knowledge. Science continues to grow as new certainties are added to the existing body of knowledge.

However, Hume raised some challenging questions regarding the validity of inductive reasoning. He pointed out that no matter how many observations we make, they cannot logically entail an unrestrictedly general statement. While science assumes that the future will be like the past, there is no way to establish this assumption through observation or logical argument. Hume concluded that we are psychologically predisposed to thinking in terms of induction, despite the lack of a secure foundation for it.

The problem of induction, also known as “Hume’s problem,” has puzzled philosophers since Hume’s time and is often described as the “skeleton in the cupboard of philosophy,” as C. D. Broad put it.

Saving the foundation of science:

It is a unique and embarrassing situation that the foundations of all science rely on principles that cannot be proven valid. This has caused many empirical philosophers to become sceptics, irrationalists, mystics or even turn to religion. Almost all of them have acknowledged that scientific laws cannot be strictly be proven and are therefore uncertain.

However, the probability of these laws is increased with each confirming instance and every moment of the world’s existence brings countless billions of confirming instances with no counter-examples. Therefore, although not certain, they are probable to the highest degree imaginable, which in practice is indistinguishable from certainty, if not in theory.

The asymmetry between verification and falsification:

Popper’s significant contribution has been to propose a solution to the problem of induction that is widely accepted. He rejects the conventional view of scientific method outlined in this chapter and substitutes it with a new approach.

Popper’s solution starts by pointing out a logical asymmetry between verification and falsification. To explain it in terms of statement logic: even though a series of observation statements that report white swan observations cannot logically deduce the universal statement ‘All swans are white,’ a single observation statement of a black swan allows us to logically deduce the statement ‘Not all swans are white.’

Empirical generalisations are falsifiable in this important logical sense, even if they are not verifiable. This implies that scientific laws are testable despite being unprovable. They can be tested through systematic efforts to disprove them.

The logic of falsification:

From the beginning Popper drew the distinction between the logic of this situation and the implied methodology. The logic is utterly simple: if a single black swan has been observed then it cannot be the case that all swans are white. In logic, therefore that is, if we look at the relation between statements a scientific law is conclusively falsifiable although it is not conclusively verifiable.

Popper therefore proposes, as an article of method, that we do not systematically evade refutation, whether by introducing ad hoc hypotheses, or ad hoc definitions, or by always refusing to accept the reliability of inconvenient experimental results, or by any other such device; and that we formulate our theories as unambiguously as we can, so as to expose them as clearly as possible to refutation.

Practical example: Suppose we start by believing, as most of us are taught at school, that it is a scientific law that water boils at 100° Centigrade. No number of confirming instances will prove this, but we can nevertheless test it by searching for circumstances in which it does not hold. This alone challenges us to think of things or ways that this theory may not hold true. With a little bit of imagination and maybe luck we discover that water does not boil at 100° Centigrade in closed vessels. So what we thought was a scientific law turns out not to be one.

Now at this point we could take a wrong turning. We could salvage our original statement by narrowing its empirical content to Water boils at 100° Centigrade in open vessels.’ And we could then look systematically for a refutation of our second statement. And if we were rather more imaginative than before we should find it at high altitudes: so that to salvage our second statement we would have to narrow its empirical content to Water boils at 100° Centigrade in open vessels at sea-level atmospheric pressure.’ And we could then begin a systematic attempt to refute our third statement. And so on. In this way we might regard ourselves as pinning down ever more and more precisely our knowledge about the boiling point of water. But to proceed in this way, through a series of statements with vanishing empirical content, would be to miss the most important features of the situation.

For when we discovered that water did not boil at 100° Centigrade in closed vessels we had our foot on the threshold of the most important kind of discovery of all, namely the discovery of a new problem:  ‘Why not?’ We are challenged now to produce a hypothesis altogether richer than our original, simple statement, a hypothesis which explains both why water boils at 100° Centigrade in open vessels and also why it does not in closed ones; and the richer the hypothesis is the more it will tell us about the relationship between the two situations.

In other words we will now have a second formulation which has not less empirical content than our first but very considerably more. And we should proceed to look systematically for a refutation of that. And if, say, we were to find that although it gave us results in both open and closed vessels at sea-level atmospheric pressure it broke down at high altitudes we should have to search for a third hypothesis, richer still, which would explain why each of our first two hypotheses worked, up to the point it did, but then broke down at that point; and also enable us to account for the new situation as well. And then we should test that.

The advancement of knowledge:

This, in a nutshell, is Popper’s view of the way knowledge advances.

If we had set out to ‘verify’ our original statement that water boils at 100° Centigrade by accumulating confirming instances of it we should have found no difficulty whatever in accumulating any number of confirming instances we liked. But this would not have proved the truth of the statement, nor would it have increased the probability of its being true.

Worst of all, our accumulation of confirming instances would never have given us reason to doubt, let alone replace, our original statement, and we would never have progressed beyond it. Our knowledge would not have grown as it has – unless in our search for confirming instances we accidentally hit upon a counter-instance. Such an accident would have been the best thing that could have happened to us.

All knowledge is provisional:

For the growth of our knowledge proceeds from problems and our attempts to solve them. These attempts involve the propounding of theories which, if they are to provide possible solutions at all, must go beyond our existing knowledge, and which therefore require a leap of the imagination.

The bolder the theory the more it tells us, and also the more daring the act of imagination. (At the same time, though, the greater is the probability that what the theory tells us is wrong; and we should use rigorous tests to discover whether it is.)

We are now in a position to see why it is inherent in Popper’s view that what we call our knowledge is of its nature provisional, and permanently so. At no stage are we able to prove that what we now know’ is true, and it is always possible that it will turn out to be false. Indeed, it is an elementary fact about the intellectual history of mankind that most of what has been ‘known’ at one time or another has eventually turned out to be not the case.

This is the characteristic situation in any of the sciences at any given time. The popular notion that the sciences are bodies of established fact is entirely mistaken. Nothing in science is permanently established, nothing unalterable, and indeed science is quite clearly changing all the time, and not through the accretion of new certainties.

If we are rational we shall always base our decisions and expectations on the best of our knowledge’, as the popular phrase so rightly has it, and provisionally assume the ‘truth’ of that knowledge for practical purposes, because it is the least insecure foundation available; but we shall never lose sight of the fact that at any time experience may show it to be wrong and require us to revise it.

How the ‘accuracy’ of measurement and truth are related:

According to Popper, the truth of a statement, meaning its correspondence to the facts, is a regulatory concept. To illustrate this idea, an analogy can be made with the concept of “accuracy.” All measurements, whether of time or space, have a certain degree of accuracy. For instance, if you order a steel piece that is precisely six millimetres long, it can be manufactured with the utmost accuracy to within the smallest possible margin, which is now fractions of a millionth of a millimetre.

However, we can never know the exact point of six millimetres within that margin. It is possible that the steel piece is precisely six millimetres long, but we can’t be certain. All we know is that the length is accurate within a certain fraction of a millimetre.

Popper’s idea of “the truth” is akin to this concept of accuracy. Our aim in the pursuit of knowledge is to get as close to the truth as possible, and we may even recognise that we have made progress, but we can never know if we have reached our ultimate goal.

Poppers revelation:

It was Einstein’s challenge to Newton’s theory that made Popper realise the inherently conjectural nature of scientific knowledge. Newtonian physics had been the most successful and significant scientific theory to have ever been put forth and accepted. All empirical evidence seemed to support it, with countless billions of observations and experiments having inductively verified scientific laws as laws of nature. For generations, it had been taught as an incontrovertible fact.

But at the turn of the century, Einstein proposed a theory that differed from Newton’s. The world had been wrong to believe that all that evidence proved Newton’s theory. Yet, an entire civilisation’s era had been founded on it, leading to unparalleled material success. If this extensive verification and inductive support did not prove the truth of a theory, then what could? Popper realised that nothing could. He recognised that no theory could ever be relied upon to be the final truth.

The most we can ever say is that a theory is supported by every observation thus far and yields more precise predictions than any known alternative. Nonetheless, it is still subject to being replaced by a superior theory.

Creating Theories:

There are three important points to consider regarding Theory Generation. Firstly, the way in which the theory was developed does not affect its scientific or logical status. Secondly, the observations and experiments used to test the theory are not the sole basis for its creation, but rather are derived in part from the theory itself. Finally, the concept of induction is not relevant to theory formation.

According to Popper, the traditional view of scientific method led to the problem of induction, but this can be replaced by a more accurate view that does not require induction. In fact, Popper argues that induction is a myth and does not exist.

However, a critic may argue that Popper overlooks the process of theory formation, in which induction plays a role. While it is true that singular observations cannot prove a general theory, they may suggest one, especially to a scientist with insight and imagination. The process of generalizing from observed instances may involve a logical progression, and this is what we call induction, despite the inherent jump from singular to general.

You can’t observe without a theory:

Furthermore, according to Popper, observation cannot be considered independent of theory because any observation requires some theory to make sense of it. The failure to acknowledge this, in his view, is a fundamental flaw in the empirical tradition. Despite this, many people still hold on to the belief that science begins with pure observations without any theoretical framework, which Popper finds absurd.

To illustrate this point to a group of physics students in Vienna, Popper started a lecture by instructing them to observe and write down what they observed. However, the students immediately asked what they were supposed to observe. The instruction “Observe!” was clearly nonsensical.

Observation is always selective and requires a specific object, task, interest, viewpoint, and problem. Additionally, its description relies on a descriptive language with property words and presupposes similarity and classification, which, in turn, presupposes interests, viewpoints, and problems. This means that observations, observation statements, and statements of experimental results are always interpretations of the observed facts, and they are interpreted in the light of theories. In sum, at every level, our knowledge can only consist of our theories, which are products of our minds.

Any hypothesis we formulate must be based on observations, such as those that require explanation. However, these observations themselves rely on a framework of reference, expectations, and theories that came before them.

The observations that demand an explanation and motivate the invention of a hypothesis do so precisely because they cannot be accounted for within the existing theoretical framework or horizon of expectations. Therefore, any hypothesis is an attempt to extend the boundaries of our current understanding by offering a new explanation that goes beyond the limitations of our current theories.


3 – The Criterion of Demarcation between what is and what is not Science

The criterion of demarcation between science and non-science is falsifiability. The crux of the matter is that if a theory can accommodate all possible states of affairs, then no empirical evidence or experimental results can be considered as supporting evidence for it. In other words, there is no observable difference between the theory being true or false, and it does not provide any scientific information. The theory can only be considered scientific if it is testable, which means that there is a conceivable observation that could refute it.

The bolder the theory the more chances it is wrong:

The traditional view, known as inductivism, holds that scientists seek statements about the world that have a high degree of probability based on the evidence. Popper, however, disagrees with this perspective. He notes that it is easy to produce predictions with high probabilities, like “it will rain,” which are practically guaranteed to be true but cannot be proven false.

Even if we restrict such statements to a specific time and place, they still offer little useful information. Instead, Popper argues that what we want are statements with high informative content, containing non-tautological propositions that can be deduced from them. However, the higher the informative content, the lower the probability, since more information increases the potential ways in which a statement can be false. Thus, it is possible for anyone to create statements with high informative content, but only at the risk of being false.

Scientists are interested in statements that are highly falsifiable and therefore highly testable. The more informative a statement is, the more easily it can be tested. A full, specific, and accurate description of the world would have the highest possible informative content, but also the highest possible number of ways in which it could be false. Therefore, every possible observation or experience would constitute a test, or a potential falsification, of it. The probability of such a statement being true would be unimaginably close to zero.

Being proved wrong as progress:

Popper observed that if scientists always opt for the most probable explanation, they will end up with an ad hoc explanation that goes no further than the existing evidence, resulting in limited progress. On the other hand, bold theorising can lead to significant breakthroughs, but is also more likely to be proven wrong. However, this possibility of being proven wrong should not be feared. The erroneous view of science is manifested in the desire to be right at all times.

Accepting the inevitability of falsification can have a positive impact on scientists, as Sir John Eccles pointed out. The mistaken belief that science leads to an ultimate and certain explanation implies that publishing a hypothesis that is eventually proven false is a serious scientific offense. Therefore, scientists often hesitate to admit the falsification of their hypotheses and end up wasting their time defending them. According to Popper, falsification is the expected outcome of all hypotheses, and scientists should even welcome the falsification of a cherished hypothesis as a step towards scientific progress.

It should always be anticipated that your hypothesis may be falsified and that it will be replaced in whole or in part by another hypothesis of greater explanatory power.

The man who welcomes and acts on criticism will prize it almost above friendship: the man who fights it out of concern to maintain his position is clinging to non-growth.

Choosing between rival theories (Corroboration):

To begin with, a theory should offer a solution to a relevant problem. Additionally, it should be consistent with all known observations and incorporate the previous theories as initial approximations, though it should refute them where they fall short and account for their shortcomings. When multiple theories are proposed to solve a problem, we must choose between them. If all things are equal, we prefer a theory with higher informative content, as it provides more information and is better tested, making it more useful and better corroborated.

Reformulating theories or evidence:

Popper’s advice is to formulate theories in a clear and concise manner, exposing them to refutation as much as possible. Additionally, he suggests that we should not evade refutation by continuously modifying either the theory or evidence to align the two. This behaviour is common among Marxists and psychoanalysts, who are substituting dogmatism for science despite claiming to be scientific.

A scientific theory does not attempt to explain everything that could possibly happen. Rather, it rules out most of what could occur, and as such, is at risk of being disproven if what it excludes actually occurs. In this way, a truly scientific theory is permanently vulnerable to refutation.

The allure of unfalsifiable theories that explain everything:

Popper often pointed out that the secret of the enormous psychological appeal of these various theories lay in  their ability to explain everything. To know in advance that whatever happens you will be able to understand it gives you not only a sense of intellectual mastery but, even more important, an emotional sense of secure orientation in the world.

Acceptance of one of these theories had, he observed, ‘the effect of an intellectual conversion or revelation, opening your eyes to a new truth hidden from those not yet initiated. Once your eyes were thus opened you saw confirming instances everywhere: the world was full of verifications of the theory. Whatever happened always confirmed it. Thus its truth appeared manifest; and unbelievers were clearly people who did not want to see the manifest truth; who refused to see it, either because it was against their class interest, or because of their repressions which were still “unanalysed” and crying aloud for treatment.

Popper has never and this cannot be too strongly emphasised – dismissed such theories as valueless, still less as nonsense This does not mean that Freud and Adler were not seeing certain things correctly: I personally do not doubt that much of what they say is of considerable importance, and may well play its part one day in a psychological science which is testable. But it does mean that those “clinical observations” which analysts naïvely believe confirm their theory cannot do this any more than the daily confirmations which astrologers find in their practice.

I thus felt that if a theory is found to be non-scientific, or “metaphysical” (as we might say), it is not thereby found to be unimportant, or insignificant, or “meaningless”, or “nonsensical”. But it cannot claim to be backed by empirical evidence in the scientific sense-although it may easily be, in some genetic sense, the “result of observation”.”

Verification and Meaning:

Popper’s work has been widely misunderstood and propagated in print as advancing falsifiability as the criterion of demarcation not between science and non-science, but between sense and nonsense. This misunderstanding is based on the belief that what is not science is nonsense, and Popper’s response to this protest was that it ultimately comes down to the same thing.

Popper himself attacked this view on several grounds. First, he argued that while singular statements may be empirically verifiable, universal statements such as scientific laws certainly are not. Therefore, the verification principle eliminates not only metaphysics but the whole of natural science.

Second, the verification principle pronounces all metaphysics to be meaningless, yet it is out of metaphysics that science has historically emerged. Ideas that are untestable and therefore metaphysical may become testable and scientific with changing circumstances.

Contrary to regarding metaphysics as nonsense, Popper held metaphysical beliefs such as the existence of regularities in nature. Finally, Popper made a devastating point against the logical positivists that if only verifiable and tautologous assertions are considered meaningful, any debate about the concept of ‘meaning’ must contain meaningless statements.

On arguments around definitions:

According to Popper, discussions on the meanings of words are not only tedious but also detrimental. Such discussions can never reach a conclusion because they require never-ending preliminaries. Popper argued that discussions must use undefined terms, and precise knowledge does not necessarily require precise definition. Physicists, for example, employ terms such as “energy” and “light” without precise definitions, yet they have the most extensive and accurate knowledge.

The belief that scientific language’s precision depends on its terms’ accuracy is merely a prejudice, in Popper’s view. Instead, scientific language’s precision lies in not overburdening its terms with the task of being precise. For instance, the terms “sand-dune” or “wind” may be imprecise, but for many purposes, they are accurate enough. If a higher degree of differentiation is necessary, the geologist can use more precise language. Similarly, in physical measurements, there is always an error range to consider, and precision does not lie in reducing this range to zero, but in acknowledging it explicitly.

To make a bold statement, it could be argued that the value of knowledge derived from any field of study (excluding language studies) is inversely proportional to the extent of discussions regarding word meanings. Contrary to popular belief, such debates only hinder clear and precise thinking, and inevitably result in endless arguments over terminology, rather than meaningful substance.

The crucial aspect of language is its function as a tool for formulating and discussing theories about the world. Therefore, a philosopher who spends their time preoccupied with the tool itself, rather than its use, is akin to a carpenter who spends their entire working day sharpening their tools but never actually using them for their intended purpose. While it’s important for philosophers to communicate their ideas clearly, they should follow the lead of physicists and ensure that their work doesn’t depend on the precise manner in which they use language.


4 – Popper’s Evolutionism and his theory of World 3

Poppers Scientific Method:

The traditional view of scientific method had the following stages in the following order, each giving rise to the next:

1, observation and experiment;

2, inductive generalisation;

3. hypothesis;

4, attempted verification of hypothesis;

5, proof or disproof;

6, knowledge.

Popper replaced this with:

1, problem (usually rebuff to existing theory or expectation);

2, proposed solution, in other words a new theory;

3, deduction of testable propositions from the new theory;

4, tests, i.e. attempted refutations by, among other things (but only among other things), observation and experiment;

5. preference established between competing theories.

Where do our first theories come from?

If we ask of Popper’s schema: where did the theory or expectation in stage 1 come from whose breakdown constituted our problem, the short answer usually is: from stage 5 of a prior process. And if we follow successive processes back, we come to expectations that are inborn, not only in human beings but in animals. The theory of inborn ideas is absurd, but every organism has inborn reactions or responses; and among them, responses adapted to impending events. These responses we may describe as “expectations” without implying that these “expectations” are conscious.

How Poppers work links to Evolution:

So Popper’s theory of knowledge is coterminous with a theory of evolution. Problem-solving is the primal activity: and the primal problem is survival. ‘All organisms are constantly, day and night, engaged in problem-solving; and so are all those evolutionary sequences of organisms – the phyla which begin with the most primitive forms and of which the now living organisms are the latest members.

In organisms and animals below the human level trial solutions to problems exhibit themselves in the form of new reactions, new expectations, new modes of behaviour, which, if they persistently triumph over the trials to which they are subjected, may eventually modify the creature itself in one of its organs or one of its forms and thus become (by selection) incorporated in its anatomy.

Error elimination may consist either in so-called natural selection which is the failure to survive of an organism that has failed to make a necessary change, or has made an inappropriate one or in the development within the organism of controls which modify or suppress inappropriate changes.

Like Darwin’s, Popper’s theory offers no explanation of the genesis of life but relates only to its development.

The emergence of the new:

According to Popper, the origin of life, theories, and works of art cannot be rationally explained. He argues in The Poverty of Historicism that in the world of physics, nothing can happen that is truly and intrinsically new, as even new inventions can be analysed as a re-arrangement of existing elements. Biological newness, on the other hand, is an intrinsic type of newness that cannot be causally or rationally explained, but only intuitively grasped. The problem of emergence and the appearance of genuinely new things are important subjects that preoccupy him, and he may have important contributions to make on this topic in the future.

According to Popper, many things in the world are not intentionally created. For instance, he poses the question: “How does an animal path in the jungle come about?” The answer, according to him, is that it is an unintended consequence of the need for easy or swift movement. One animal may break through the undergrowth to get to a drinking place, and other animals may follow the same track, widening and improving it over time.

Popper believes that language and other useful institutions can also arise in this way, owing their existence and development to their usefulness rather than to any intentional planning. Although they were not planned or intended, they may create new needs or aims. Popper suggests that the aim-structure of animals and humans is not predetermined but instead develops through some sort of feedback mechanism based on earlier aims and results that were either intended or not.

Worlds 1, 2 and 3

Popper posits the existence of three worlds in his account of the evolution of life and the development of civilisation: World 1, the objective world of material things; World 2, the subjective world of minds; and World 3, the world of objective structures that are products of minds or living creatures, but once produced, exist independently of them. This third world includes highly complex structures built by animals, such as nests, honeycombs, and dams, which become central to the animal’s environment and behaviour.

In human society, World 3 encompasses ideas, art, science, language, ethics, and institutions encoded and preserved in World 1 objects such as books, machines, and records. These creations have a central importance in the environment and shape the individual’s adaptation to them. The objective existence of these structures allows for evaluation, criticism, exploration, extension, revision, and unexpected discoveries.

The most significant development in the history of World 3 has been the emergence of criticism and the acceptability of criticism. In primitive societies, questioning the truth of the interpretation of the world articulated in myths or religion is punishable by death. Institutions such as mysteries, priesthoods, and schools develop to preserve the truth unsullied. Schools, however, do not admit new ideas, and heretics who attempt to change the doctrine are expelled. Even the inventor believes they are returning to the true orthodoxy that has been perverted.

Popper’s philosophy offers a promising growth point in the concept of a third world, which is both man-made and autonomous. This idea is the subject of one of his unpublished books, which explores how interaction with World 3 contributes to the development of the self. Popper’s theory provides a rational explanation for evolutionary processes without requiring an overall plan or plot, as Marx believed, or an internal spirit or vital force, as Hegel believed. This illuminating idea has the potential to be highly productive in various applications.

Killing our ideas:

Popper argues that the pre-Socratic philosophers of ancient Greece, starting with Thales and his pupils Anaximander and Anaximenes, were the first schools in history to not only allow criticism but also encourage and welcome it. This marked the end of the dogmatic tradition of blindly passing on an unblemished truth and the beginning of a new rational tradition of subjecting ideas to critical discussion. This was the inauguration of scientific method.

In the prescientific era, a person’s theories were a matter of life or death, just like animals and lower organisms. “We perish with our false theories.” In contrast, in the scientific era, we systematically attempt to eliminate our false theories and allow them to die in our place. When humans no longer faced the death of their theories, they became emboldened to explore. Previously, the entire weight of intellectual tradition was defensive and served to preserve existing doctrines. But now, for the first time, it supported a questioning attitude and became a force for change.

When man no longer shared the death of his theories he was emboldened to venture. Whereas, before, the entire weight of intellectual tradition had been defensive and had served to preserve existing doctrines, now, for the first time, it was put behind a questioning attitude and became a force for change.”


5 – Objective Knowledge

All life is problem solving:

Throughout the story of the evolution from the amoeba to Einstein, a consistent pattern emerges. The provisional solutions that are incorporated into the anatomy and behaviour of animals and plants are analogous to biological theories, while theories and exosomatic products like honeycombs and tools like spiders’ webs correspond to endosomatic organs and their modes of operation.

Organs and their functions, like theories, are tentative adaptations to the environment. As with theories and tools, new organs, functions, and behaviours also have an impact on the first world, which they may help to transform.

Popper has characterised the underlying pattern of this continuous development in the formula

P₁→TS -> EE -> P₂

where P₁ is the initial problem, TS the trial solution proposed, EE the process of error elimination applied to the trial solution and P, the resulting situation, with new problems. It is essentially a feedback process. It is not cyclic, for P₂ is always different from P₁: even complete failure to solve a problem teaches us something new about where its difficulties lie, and what the minimum conditions are which any solution for it must meet and therefore alters the problem situation.

All learning process can be looked at in this way, even the process by which human beings get to know each other. The psychiatrist Anthony Storr, without having read Popper, arrived at the following conclusion: “When we enter a new situation in life and are confronted by a new person, we bring with us the prejudices of the past and our previous experiences of people. These prejudices we project upon the new person. Indeed, getting to know a person is largely a matter of withdrawing projections; of dispelling the smoke-screen of what we imagine he is like and replacing it with the reality of what he is actually like.”

Practical applications of this idea:

The adoption of this approach has certain natural consequences. Firstly, it directs attention towards problems, not only for oneself, but also in the appreciation of the efforts of others. The task begins with the problem itself and the reasons for its existence, rather than attempting to solve it. One learns to spend considerable effort and time formulating problems before turning attention to the search for potential solutions. Success in the latter is often determined by success in the former.

In studying the work of a philosopher, for example, the initial question one should ask is: “What problem is he trying to solve?” This question is often overlooked, and instead, individuals ask, “What is he trying to say?” Consequently, individuals may believe they understand what the philosopher is saying, but fail to see the point behind it. Understanding the problem-situation is crucial for comprehension.

Another consequence, which is essential to Popper’s philosophy, is the realisation that complex structures, whether intellectual, artistic, social, administrative or otherwise, are created and changed through successive stages of critical feedback and adjustments.

This evolutionary perspective inevitably leads to a concern with developments over time. Rather than being a record of past errors, the history of science or philosophy is seen as a continuous argument, a series of interconnected problems and their tentative solutions. As we move forward in the present, we hold one end of this chain.

We are inevitably shaped by our past, both as individuals and as a society, and it is impossible to completely detach ourselves from it. As a result, tradition holds a crucial significance in our lives, as it is the foundation upon which we build, whether by following it or rebelling against it. Progress is often made by challenging tradition and effecting changes, using it as a starting point to move forward.

One should pay attention to disagreements and identify where difficulties arise. These are the questions that one should tackle. This means studying the current problem situation by continuing a line of inquiry that has the entire history of science behind it and aligning with the scientific tradition.

We do not know where or how to start our analysis of this world. There is no wisdom to tell us. Even the scientific tradition does not tell us. It only tells us where and how other people started and where they got to.


6 – The Open Society

The Problem Solving Society:

Most major political philosophies, such as those of Plato and Marx, are deeply rooted in their views on social and historical development, logic, science, and epistemology. Similarly, Popper’s philosophy also draws from these areas. Popper believes that life is primarily a process of problem-solving, and he desires societies that are conducive to this process. To facilitate problem-solving, he advocates for the free expression of diverse ideas, followed by rigorous criticism and error elimination, allowing for the possibility of change. Therefore, Popper’s political philosophy aligns with his view on problem-solving, valuing the ability to propose and critique ideas freely in the pursuit of progress.

Policies as Hypothesises:

Empirical predictions are integral to all executive and administrative decisions, including government policies. Such predictions are formulated as hypotheses like “If we do X, Y will follow,” or “To achieve B, we must do A.” However, these predictions are prone to error and often require modification as they are put into practice. Policies must be tested against reality and corrected based on experience, much like hypotheses. A more rational approach involves critical examination and discussion beforehand to detect mistakes and inherent dangers. This approach is generally less wasteful of resources, people, and time   waiting for mistakes to reveal themselves in practice.

Merely having clear policies or goals is insufficient for anyone in a position of power, whether in government or a smaller organisation. The means to achieve those policies or goals must also exist, and if they do not, they must be established. Consequently, organisations and institutions must be viewed as machines for implementing policies in one regard.

To determine if a policy is successful, its implementation must be evaluated by searching for evidence that it is not working, rather than looking for proof that one’s efforts are having the desired effects. In practice, testing in this sense is often inexpensive and straightforward, as precise accuracy is rarely required.

Large amounts of money and effort are frequently expended on misguided policies without any consideration given to the small sums and efforts required to check if undesired outcomes are arising. People in organisations frequently disregard evidence that contradicts their desired outcomes, despite the fact that this is exactly what they should be searching for. Additionally, in authoritarian structures, the constant quest for and recognition of errors, even at the organisational level, is particularly challenging. This irrationality extends into the very mechanisms that they employ.

Unintended Consequences:

The implications of the simple point that any action we take is likely to have unintended consequences are highly charged for politics, administration, and any form of planning. For example, if I want to buy a house, my very appearance in the market as a buyer will tend to raise the price, which is a direct consequence of my action but not an intended one. Similarly, if I take out an insurance policy to raise a mortgage, this will tend to raise the value of the insurance company’s shares, which again has no connection with my intentions. Therefore, decision making and the creation of organisational structures must take into account the inescapable fact that things are all the time happening which nobody planned or wants, as failing to do so will be a permanent source of distortion.

Poppers idea of Democracy:

The idea that rationality, logic, and a scientific approach require a centrally organised, planned, and ordered society has been widely held, especially in our century. However, Popper has shown that this notion is both authoritarian and based on an outdated understanding of science.

Instead, a rational, logical, and scientific approach points towards an “open” and pluralistic society where conflicting views and goals are expressed and pursued. In such a society, everyone is free to investigate problem situations and propose solutions, while also being free to criticise the proposed solutions of others, including the government’s policies. Most importantly, the government should be willing to change its policies in response to criticism.

In order to bring about significant changes in policies, it is often necessary to replace the people who advocate and oversee their implementation. Thus, for an open society to exist, it is crucial that those in power can be removed and replaced by others with differing policies without resorting to violence, and at regular intervals.

To achieve this, individuals with opposing policies must be allowed to form an alternative government and have the freedom to organise, express their opinions through speech, writing, publishing, broadcasting and teaching, and be guaranteed constitutionally protected access to a means of replacing the current government, such as through regularly held free elections.

Popper refers to such a society as “democracy,” although he does not place any particular emphasis on the term.

Paradox of Tolerance:

Popper identifies additional paradoxes that his approach sidesteps. One of these paradoxes is the paradox of tolerance, which has already been implied. According to this paradox, if a society grants unlimited tolerance, it is likely to be annihilated along with tolerance. Therefore, a tolerant society must be willing, in certain situations, to quell the adversaries of tolerance. However, it should not do so unless they pose a real threat. Otherwise, it may result in a witch-hunt. Moreover, the society must endeavour to engage in rational argumentation with such individuals before resorting to suppression.

The paradox of Freedom:

The paradox of freedom, first implicitly stated by Plato, is well-known. Unrestricted freedom, just like absolute tolerance, is not only self-destructive but also likely to create its opposite. If all limitations were removed, there would be nothing to prevent the strong from enslaving the weak. Complete freedom would result in the end of freedom, making the advocates of such freedom, regardless of their motives, the adversaries of freedom.

This brings us back to the inevitability of control, which must entail the removability of the government by the governed, as an essential condition for democracy. However, this alone is insufficient to ensure the preservation of freedom, for nothing can guarantee it. The cost of freedom is eternal vigilance. As Popper observed, institutions are like fortresses, requiring not only proper construction but also proper staffing to be effective.

The fundamental question is not ‘Who should rule?’ but ‘How can we minimise misrule, both in terms of the likelihood of its occurrence and its consequences when it does happen?’

Poppers guiding principles:

The core principle of public policy outlined in The Open Society is to “minimise avoidable suffering”, which has the immediate effect of highlighting social problems. This approach, rooted in Popperian philosophy, is a practical and change-oriented one that focuses on addressing specific social issues that cause human suffering, rather than pursuing an unattainable Utopian ideal. It is grounded in a concern for human beings and a constant willingness to reform institutions.

Another formulation of this principle is to “maximise the freedom of individuals to live as they wish”. This requires substantial public investment in education, the arts, housing, healthcare, and other social domains, with the goal of expanding the range of choices and opportunities available to individuals and thus increasing their freedom.


7 – The Enemies of the Open Society

While the philosophy of social democracy is highly relevant today, it was not the primary reason why Popper wrote The Open Society and Its Enemies. At the time he was working on the book, Hitler was rapidly conquering Europe and Western civilisation was faced with the threat of a new Dark Age. Popper was driven to understand the appeal of totalitarian ideas and to undermine them, while also promoting the value and significance of liberty in its broadest sense. His aim was to combat the immediate danger posed by the rise of totalitarianism and preserve the ideals of freedom and democracy.

Poppers ideas around totalitarianism:

At the core of Popper’s analysis of the appeal of totalitarianism lies a socio-psychological idea which he refers to as the ‘strain of civilisation’ – a notion related to the one Freud presented in his book, Civilisation and Its Discontents. It is often said that most people do not truly desire freedom, as it entails responsibility and most people are afraid of it. While it may not apply to everyone, there is certainly a significant element of truth in this assertion. Being accountable for our own lives means we have to face difficult choices and decisions continually, and bear the consequences when we make mistakes, which can be daunting and burdensome.

However, as our primary instinct is survival, our greatest need is likely security, which means we are willing to transfer responsibility to someone or something that we have more faith in than ourselves. This is why people prefer their leaders to be superior to them, and why they adopt so many improbable beliefs that reinforce their confidence that this is the case, and why they are so seriously disturbed when they discover that it is not. We desire the tough decisions that shape our lives to be made by someone who is more robust than us but still has our best interests at heart, like a stern yet kind father. Alternatively, we want a practical system of thought that is wiser than us and makes fewer or no mistakes. Most importantly, we want to be free from fear.

As humanity moved away from tribalism and embraced critical thinking, new and unsettling expectations arose: individuals were called upon to question authority, challenge their assumptions, and take responsibility for themselves and others. This departure from traditional certainties threatened both society with disruption and individuals with disorientation. Hence, from the outset, there was a backlash against it, both in society as a whole and, as Freud pointed out, within each individual.

Freedom comes at the expense of security, equality at the cost of our self-esteem, and critical self-awareness at the expense of our peace of mind. The price is high, and few are happy to pay it, while many do not want to pay it at all.

Since the time of the pre-Socratics, the development of civilisation has been accompanied by a parallel tradition of reaction against the “strain of civilisation”. This tradition has produced philosophies advocating a return to the perceived security of pre-critical or tribal societies, or an advance towards a Utopian society. These reactionary and Utopian ideals share deep affinities, as they both reject existing society and proclaim the existence of a more perfect one in the future. Therefore, both tend to be violent yet romantic. The desire for a perfect society is not rooted in human wickedness, but in the opposite – the most horrific excesses have been committed by idealists with sincere moral convictions, such as those of the Spanish Inquisition. While the practical consequences of reactionary and Utopian theories can result in societies like those of Hitler and Stalin, the ultimate aim of both is to create an arrested society by halting the processes of change.

It is not only foolish individuals who are drawn towards the path of rejecting civilisation. In fact, those with intelligence and imagination are more likely to feel dissatisfied with existing society, whereas the unintelligent and unimaginative tend to accept things as they are and be more conservative. The rebellion against civilisation, which is essentially a rebellion against the realities of freedom and tolerance, with their attendant consequences of diversity, conflict, unpredictability, and insecurity, has been led by some of the greatest intellectual leaders in human history.

Popper and Historicism:

Popper coined the term ‘historicism’ to describe an approach to the social sciences that assumes historical prediction as its principal aim. Historicism assumes that this aim is achievable by discovering the underlying “rhythms,” “patterns,” “laws,” or “trends” that govern the evolution of history.

However, if historical inevitability is to be seriously argued, a limited number of explanations are possible. One is that history is being directed by some outside intelligence, usually God, in accordance with its own purposes. Another is that history is being driven forward by some inside intelligence, such as immanent spirit or life force, or the “destiny of man.” Both of these alternatives are metaphysical and not falsifiable, and therefore not scientific.

The third alternative is that entirely deterministic material processes are at work, but this rests on a conception of science that is no longer tenable. It is clear that human history has been strongly influenced by the growth of knowledge, but it is logically impossible to predict future knowledge. If the future contains any significant discoveries, it is impossible to predict it scientifically, even if it is determined independently of human wishes.

Moreover, if the future were scientifically predictable, it could not remain secret once discovered because it would be re-discoverable by anyone. Therefore, Popper argues that the notion of historical prediction is fundamentally flawed, and that history should be studied through the lens of critical rationalism, which emphasises the importance of conjectures and refutations rather than prediction.

The planned society:

The collapse of the idea that the future can be predicted scientifically also undermines the concept of a completely planned society. This highlights a flaw in the assumption made by Utopians, that any undesirable event in society, such as poverty, war, or unemployment, is the result of some malevolent intent, and that somebody profits from it. Popper calls this view the conspiracy theory of society.

Popper’s arguments against political approaches that begin with a fixed plan and attempt to actualize it must be confronted by any idealist who wants to maintain their idealism without illusions. First, any attempt at change must begin from the existing circumstances, and it is impossible to start from scratch. Utopians claim that the entire society must change before anything else can be changed, which is self-contradictory.

Secondly, any action we take will have unintended consequences that may conflict with our blueprint, and the more extensive the action, the more unintended consequences. To claim that sweeping plans to transform society as a whole are rational is to assert a degree of sociological knowledge that we do not possess.

Additionally, people hold different views on the kind of society they desire, and even traditional political groups like Conservatives, Liberals, and Socialists have divergent opinions. Any government that attempts to implement its blueprint for society as a whole will have to overcome opposition from others who disagree with it. A free society cannot impose common social purposes, but a government with utopian goals has to, and will become authoritarian as a result.

Attempting to eliminate everything at once would create chaos, and the notion that an ideal society would emerge from that chaos is absurd. Even if we could start over, we could never achieve a static, unchanging society because change is perpetual. Ideal societies are unattainable not only because they are ideal, but also because they would need to be unchanging, and no society can remain that way. The pace of social change seems to be accelerating, and there is no end to the process in sight.

The ideal society:

As society can never achieve perfection, discussing the “ideal” form of society is pointless, according to Popper. In fact, he rejects all “what is?” questions, including those about gravity, life, freedom, and justice, as they do not aid progress in science or politics. He also criticises disguised “what is?” questions, such as “Is Britain a democracy?”, which ultimately lead to the question of what democracy truly means. Popper calls the attempt to define reality through such questions “essentialism,” a quasi-magical approach that fails to capture the complexity of reality.

The essentialist approach in politics often leads to Utopianism and ideological conflicts. The more pertinent questions are those that ask “What should we do in these circumstances?” and “What are your proposals?” These questions allow for productive discussion and critique, and proposals that withstand scrutiny can be tested out. Only proposals that can be put into practice have any practical value. Thus, what counts in politics, just as in science, is not the analysis of concepts but the critical examination of theories and their testing against real-world experience.