critical rationalism blog

The bibliography prepared by Antoni Diller.

And another list of on-line papers by Bartley.

The Bartley page in the Rathouse.

A large fragment of the Popper biography by Bartley.

Adding a few words to the Guide to the LSD on Corroboration. The idea is to introduce the “check on the problem” to ask people to consider what they are trying to achieve with confirmation theory. The check on the problem is  a good way to focus a discussion that has drifted off into definitions, or just drifted off as so many committees and meetings tend to do.

Popper rejected the possibility of verification of theories, and also the fallback position of numerical probability of theories. So he had to answer the question – what is achieved when a hypothesis passes empirical tests? His answer is the theory of corroboration.

He adopted this term (suggested by the New Zealand soil chemist Hugh Parton) to distance himself from Carnap who wanted to talk about the “degree of confirmation”.

Most of this chapter is occupied with arguments against the idea of attaching numerical probability values to theories by means of inductive logic. One of the defences mounted by the inductivists is to appeal to the uniformity of nature as an “inductive principle” which we cannot live without. For Popper, the uniformity of nature has nothing to do with the logic of induction (attempting to put p values on theories) but,

“It expresses the metaphysical faith in the existence of regularities in our world (a faith which I share, and without which practical action is hardly conceivable). Yet the question before us – the question which makes the  non-verifiability of theories significant in the present context – is on an altogether different plane. (252-3)”

The plane that concerned Popper is the logic of testing and the way that the outcome of tests is inevitably uncertain due to the theory-dependence of observations, the Duhem problem and the like. And so the outcome for Popper is that corroboration is about reporting how well a hypothesis has “proved its mettle” by standing up to tests and solving whatever theoretical problem it was designed to address. It may help at this point to consider what Bartley called “the check on the problem”, that is to be clear about the problem that a theory of corroboration (or confirmation) is supposed to solve. Originally it was probably supposed to answer the question, “Is this theory true?” and later “Is this theory probable?”. For Popper, operating with the theory of conjectural knowledge and also considering what he called “the essential incompleteness of all science” (in an Addendum to the second volume of the <i>Postsript to The Logic of Scientific Discovery</i>), the purpose of testing depends on the situation: there may need to be a choice for a practical or technological application, or there may need to be a decision about the next steps of a research program. 

“We choose the theory which best holds its own in competition with other theories; the one which, by natural selection, proves itself the fittest to survive. This will be the one which no only has hitherto stood up to the severest tests, but the one that is testable in the most rigorous way. (108)”

This is a new chapter in the Guide to The Open Society to cover the 1962 addendum on Facts, Standards and Truth: A Further Critique of Relativism

This essay is the result of intensive discussion with William W. Bartley following Bartley’s efforts to improve on the “critical rationalism” of Chapter 24 which he thought allowed too much to the element of “faith” in reason. Bartley’s inspiration for this project was Popper’s lecture “On the Sources of Knowledge and of Ignorance” which he heard when Popper read it to the British Academy in 1960.  It was published as the Introduction to Conjectures and Refutations.

Popper considered that the main philosophical malady at the time was intellectual and moral relativism or scepticism in its corrosive form (as opposed to the  “critical rationalist” form of scepticism which is simple willingness to subject all ideas to criticism). He defined relativism as

(a)    the claim that the choice between competing theories is arbitrary, because

(b)   either there is no such thing as objective truth, or

(c)    even if there is, there is no way to make a rational choice between rival theories.

Popper thought that these objections could be overcome with the help of Tarski’s theory of truth and his own  non-authoritarian theory of knowledge. He briefly explained how Tarski retrieved the theory of truth as a regulative principle, not a terminus of inquiry based on a criterion of truth.

The problem of criteria and sources of knowledge

He argued that we do not need a criterion of truth, or the meaning of a word, in order to conduct our investigations and our arguments and he noted the insoluble problems that arise from the assumption that there is (or should be) a criterion of truth( in the final or foundational sense). He explained the importance of fallibillism in the quest for knowledge, the idea of getting nearer the truth and the importance of a  particular form of absolutism, that is, the idea of absolute error or falsehood.

He returned to the issue of sources of knowledge to emphasise that there are several  sources  (starting with tradition, the state of knowledge that we first encounter)  but none can be regarded as an authority. The critical approach to tradition and all forms of knowledge creates the problem of decisions that are required about the best or the most appropriate theory or policy proposal. The point is to maintain a tentative attitude towards decisions.

This line of thought applies to social and political problems. Popper considered that the intellectual climate at the time was corrupted by widespread relativism and nihilism, possibly related to the decline of authoritarian religion. He considered that the position adopted by many intellectuals was based on very poor reasoning, suggesting that they did not so much reject reason as much as they failed to use reason effectively. He was confident that the non-authoritarian theory of knowledge  and critical rationalism provided an antidote to their condition, even if it might appear at first sight too abstract and sophisticated to replace religion.

“that may be true . But we must not underrate the power of the intellect and the intellectuals. It was the intellectuals – the second-hand dealers in ideas as Hayek calls them – who spread relativism, nihilism and intellectual despair. There is no reason why some intellectuals should not eventually succeed in spreading the good news that the nihilistic ado was indeed about nothing.”

Propositions and proposals

He touched on the point made in the chapter on moral standards (“Nature and Convention”) to refer to the dualism of facts and decisions as a dualism of  propositions  and  standards or  proposals. The reason for the change was to remind us that both propositions and proposals are open to rational discussion.  At the same time an important difference remains:

“For the proposal to adopt a policy or standard, its discussion, and the decision to adopt it, may be said to create this policy or standard [such as a set of traffic rules]. On the other  hand, the proposal of a hypothesis, its discussion, and the decision to adopt it [as a tentative critical preference] does not, in the same sense, create a fact.”

That means that there is a decisive asymmetry between standards and facts and another asymmetry is that standards pertain to facts and facts are evaluated by standards; and these relation cannot be turned around.

“Whenever we are faced with a fact – and more especially, with a fact which we may be able to change – we can ask whether or not it complies with certain standards. It is important to realize that this is very far from being the same as asking whether we like it…Moreover, our likes and dislikes are facts which can be evaluated like any other facts”.

Powerful likes and dislikes for people, sporting teams, political parties and policies can persist for a long time after the original motive has been forgotten and the like or dislike has ceased to have any rhyme or reason.

Experience and Intuition as Sources of Knowledge

This is closely related to the issue of criteria and authorities for knowledge and moral insights.  We can appeal to experimental and observational evidence in discussion of theories and proposals but the data of experience are theory-based and do not provide any kind of foundation for beliefs. Evidence that supports well-tested theories may very well appear to be compelling and indeed much of our knowledge can be (indeed  has to be) regarded as unproblematic for the time being. Popper compared the situation in knowledge about moral and ethical standards where people have sought some basis that might be as sound and compelling as empirical evidence in science.

“Philosophers have looked for the authoritative sources of this knowledge, and they found in the main two: (1) feelings of pleasure and pain, or a moral sense or a moral intuition for what is right or wrong (analogous to perception in the epistemology of factual knowledge) or (2) a source called ‘practical reason’ (analogous to ‘pure reason’,  or to a faculty of ‘intellectual intuition’ in the epistemology of factual knowledge). And quarrels continually raged over the question whether all, or only some, of these authoritative sources of moral knowledge existed”.

Popper denied that there are moral authorities, any more than scientific authorities, and he denied that we need any such definite frame of reference for our critical deliberations on moral and ethical issues.

On the question of how we learn about standards? First by imitation, usually learning that they are fixed or given,  then my a  more deliberate process of trial and error as we try to learn from mistakes in our actions and our policies. Of course we have something like an intuition of right and wrong and there is a philosophical school of “intuitionism” which teaches that we have a faculty of intuition which enables us to  see the truth.

“Anti-intuitionists have usually denied the existence of this source of knowledge while asserting, as a rule the existence of some other source such as sense perception. My view is that both parties are mistaken, for two reasons. First, I assert that there exists something like an intellectual intuition wyich makes us feel, most convincingly, that we see the truth (a point denied by the opponents of intuitionism). Secondly, I assert that this intellectual intuition, though in a way indispensable, often leads us astray in the most dangerous manner”.

Of course the answer is to adopt a tentative view on standards and scientific theories, and to be prepared to reconsider them in the light of problems and objections.

Finally Popper addressed the objection that  his views, at the end of the day  are still relativist or subjectivist because they do not establish any absolute moral standards.  To which Popper replied that for practical purposes it would not help to have some absolute standard  to support our own position because opponents could simply refuse to accept out absolute standard in favour of their own.

“Only one who is prepared to take these things seriously and to learn about them will be impressed by ethical (or any other) arguments. You cannot force anybody by arguments to take arguments seriously, or to respect his own reason”.

The five Guides have been revised and when the new versions are on line I will advise Amazon so they can offer previous buyers the opportunity to update.

Preface to The Guide to The Logic of Scientific Discovery

In this revised edition there is discussion of six Popperian “themes” in place of the six “turns” in the first edition because some readers thought that these represented changes in Popper’s thinking. In fact from his first publications in 1934/5 Popper turned away from the traditional concerns with the justification of beliefs, subjective knowledge and the analysis of concepts. He also rehabilitated philosophy and metaphysics which were rendered meaningless by the standards of the Vienna circle and the logical positivists at the time.

Many angles could be adopted to provide a guide to Popper’s though. In his own words “It so happens that the real linchpin of my thought about human knowledge is fallibillism and the critical approach” (1983, xxxv).   In his lectures and the series of  papers in the 1960s that became Objective Knowledge  problem-solving is a central motif spelled out in the four-stage schema to demonstrate the all-important process of testing and critical appraisal which leads to the emergence of deeper problems which are the growing points of science. He always emphasised the importance of the historical approach and that leads to “situational analysis”  which is equally helpful  to explore  scientific or intellectual problems  and the explanation of human action and events in the social sciences.

There are two reasons to highlight the six themes. The first is to help students to get their bearings in Popper’s books because they may feel “lost” due to the lack of familiar “landmarks” such as  of justificationism,  subjectivism and conceptual analysis. His work can be seen as a program to explore the results when old problems are reformulated and addressed in new ways. Agassi provided a hint to this process with his paper on the novelty of Popper’s philosophy of science (Agassi, 1968) where he described how major advances can be achieved when a “known but unappreciated solution to a given  problem” is take seriously and the implications of the solution are unpacked.

One way to evaluate Popper’s achievement is to assess the progress that he made, given his own intentions and aspirations. Critics who understand the program of critical rationalism can then  do a “compare and contrast” exercise and make informed decisions about the direction to take their own research programs. If they decide to reject all or part of the  Popperian program that will be a rational  choice,  with reasons that can be discussed and subjected to criticism.

The second reason to describe the themes is to identify some shared concerns with other intellectual traditions and work in progress. Four of these are: (1) the fallibillism of C S Peirce and John Dewey, and currently Kitcher (2012), (2) the focus on ignorance (what we do not know) of Firestein (2012) and Schulz (2010),  (3) examination of  the social and institutional context of science by (Goldman, Kitcher)  and (4) the various ways that research programs have been discussed  by others, for example Lovejoy’s historical study of  key ideas, Collingwood’s alertness to metaphysical theories and more recently Kitcher’s concepts of “scientific practice” and “schemata” and Barry Smith’s work on the Austrian/Aristotelian metaphysical.

New material

The Appendix on The Progress of Popper contains additional commentary on the three volumes of the Postscript to The Logic of Scientific Discovery including summary statements about three interesting additions to the second volume The Open Universe.

These are “An Afterword” and two important addenda. “Indeterminism is not enough: An afterword” originally appeared in the monthly magazine Encounter in April 1973. It was the first introduction for the educated public to Popper’s new line of evolutionary thinking and the “three world” theory which he presented in a series of conference papers during the 1960s.

The first addendum  “Scientific reduction and the essential incompleteness of all science” is a rejoinder to all the over-optimistic scientists who have ever proclaimed that the “end of the road” is near, that science (usually physics) is on the verge of delivering The Final Theory About Everything. He pointed out that Godel’s incompleteness theorem of formal arithmetic provides a formal demolition of the “end of the road” aspiration, although he regarded that as “heavy argument against a comparatively weak position”. Popper’s world (of propensities) is a world of emergent evolution, emergent novelty, where problems may be solved but in the process deeper problems appear.

Nevertheless, the method of attempting reductions is most fruitful, not only because we learn a great deal by its partial successes, by partial reductions, but also because we learn from our partial failures, from the new problems which our failures reveal. (162)

The second addendum “Further remarks on reduction, 1981” begins with a fascinating account of the discovery of many new elements, starting with element 72, as a result of Bohr’s quantum theory of the periodic system of elements. This looked like an epic achievement in reducing chemistry to physics because the theory led to the discovery of new elements, and more than that, it led to the prediction of some of their optical properties and some properties of their chemical compounds. “It was a great moment in the history of matter. We felt, rightly, this was it: Bohr had hit rock bottom.” (164)

But soon the dream of reduction was dashed due to work by Soddy (1910), Thomson (1913), Aston (1919).

And then came Urey’s bombshell, the discovery of heavy water, which meant that all the basic measurements of chemistry, the measurement of the atomic weights, were slightly wrong and had to be revised. Thus the rock bottom suddenly gave way: somehow Niels Bohr had built on a morass. But his edifice still stood. (165)

The addendum finished with a reference to Prigogine ‘s (1980) work on thermodynamics which explored the way that open systems can defy the usual understanding of the law of increasing disorder in the universe, due to the increase of entropy. It seems that some systems can export entropy into their environment and increase rather than decrease their internal order.

Prigogine’s work may be looked upon as a piece of exciting physicalist reduction, at least in the sense that it takes the first steps towards a physical understanding of the evolution of higher structures, which seems to be a fairly obvious aspect of the evolution of life on earth. It may thus open the way to understanding the reason why the creativeness of life does not contradict the laws of physics. (174)

An additional appendix indicates how Jarvie identified the institutional theme in Popper’s work, another takes up the institutional theme with an examples from his political philosophy  and another indicates the wide-ranging program that he was pursuing during the 1950s in addition to translating Logik der Forschung and writing The Postscript to The Logic of Scientific Discovery (listed as an Appendix to Chapter 1 in Conjectures).

In the Guide to the Poverty the The Window of Opportunity – the parallel work of Parsons, von Mises and Popper is now an appendix instead of a part of the text of the guide.

No special changes in C&R apart from the turn from turns to themes and inclusion of the additional appendix on Jarvie and his book The Republic of Science (standard in all the guides).

In the  guide on Objective Knowledge there are the standard changes and also elimination of a lot of repetition in the supplementary material.

Minor mistakes keep turning up, especially when new material is added or passages are revised to be more readable.

Comments and criticism are welcome, at least in principle:) and the process of revision and improvement will never be complete.

NEXT STEPS

A collection of my papers on the work of Bill Bartley.

Back to work on “Misreading Popper” which is well advanced and will be done by Christmas, another task that could go on for ever but it will be brought to a close to keep the book under 50,000 words.

In part one, I defended Popper and his criterion of falsifiability from the Duhem-Quine thesis. I examined Popper’s position and revealed that not only was Popper aware of the Duhem-Quine problem before most of his critics, but that he also proposed a methodological solution to it. In part two, I will attempt to demonstrate that the Duhem-Quine thesis is either false, insofar as it’s interesting, or trivial, insofar as it’s true. In either case, the Duhem-Quine thesis no longer stands as a refutation of Popper’s criterion of falsifiability.

PART TWO

The positivists demanded that all meaningful propositions be empirically decidable–both verifiable and falsifiable. Difficulties arose, however, with respect to scientific hypotheses, because they couldn’t be verified. For example, scientific hypotheses aren’t just about the past but also the future, and it’s impossible to verify an event which hasn’t happened yet. Even putting aside doubts regarding the veracity of our observations, it’s seemed impossible to verify scientific hypotheses. Therefore, scientific hypotheses were apparently meaningless. The positivists attempted to solve this problem by using an alternate logic–induction. Supposedly, the mistake had been to presume that meaningful propositions must be deductively verifiable. If, instead, meaningful propositions need only be inductively verifiable (while remaining deductively falsifiable) then the meaningfulness of scientific hypotheses could be restored. However, problems arose with respect to the logic of induction–what justifies the use of induction? What exactly is inductive verification, and why is it epistemically valuable? How do we measure the strength of inductive inferences? What is the relationship between induction and parsimony? And more besides. The positivists had sought to reduce all meaningful discourse to the contents of, and logical derivations from, sense experience. But they encountered insurmountable difficulties that forced subsequent generations to abandon their programme. Continue reading →

Something I thought of today.

Suppose three logically possible worlds. Each world is identical except for the colour and shape of your gem.

World 1: The gem is blue and oval
World 2: The gem is not-blue and oval
World 3: The gem is not-blue and not-oval

Suppose that world 1 is the actual world while world 2 and world 3 are possible worlds.

Intuitively, it seems that world 2 is closer to world 1, the actual world, than world 3, because world 2 is different from world 1 only with respect to the colour of the gem, while world 3 is different from world 1 with respect to the colour and shape of the gem. In the space of logical possibilities, then, the proximity of world 1 and world 2 seems greater than world 1 and world 3. That is, world 1 and world 2 are closer or more alike than world 1 and world 3 … at least in English.

Suppose, instead, we spoke Inglish.

In Inglish, something is ‘bluval’ if it’s blue and oval or not-blue and not-oval; and something is ‘not-bluval’ if it’s not-blue and oval or blue and not-oval. After translating our three worlds into Inglish, we get:

World 1: The gem is blue and bluval
World 2: The gem is not-blue and not-bluval
World 3: The gem is not-blue and bluval

The words ‘blue’ and ‘not-blue’ exist in Inglish, but the words ‘oval’ and ‘not-oval’ don’t. In Inglish, something is ‘oval’ if it’s blue and bluval or not-blue and not-bluval, while something is ‘not-bluval’ if it’s not-blue and bluval or blue and bluval. Anything you can say in English can also be said in Inglish. To the English speaker, ‘bluval’ is derivative of ‘blue’ and ‘oval’, but to the Inglish speaker, ‘oval’ is derivative of ‘blue’ and ‘bluval’.

Now, by describing our three worlds in Inglish rather than English, world 3 is now closer to world 1, the actual world, than world 2. In the space of logical possibilities, the proximity of world 1 and world 3 seems greater than world 1 and world 2. That is, world 1 and world 3 now appear closer or more alike than world 1 and world 2 … at least in Inglish.

It seems to me this has important ramifications for possible world semantics: the proximity of possible worlds is a function of the ontological prejudices of each language. It would seem, then, that if we conceive of possible worlds as purely logical constructs, then there is no such thing as a possible world that is closer to the actual world than any other. All possible worlds, including the actual world, are equidistant from each other.

Anyone encountered this argument before? I admit, it’s not all that original, because I’m borrowing from arguments about verisimilitude that I read once (from Miller?), but I haven’t known them to be brought against the idea of close possible worlds.

Curently working on second editions of the guides, taking on board feedback and comments. People who have purchased copies of the guides will be able to obtain the new versions without extra charge.

A significant change in presentation is to refer to the “turns” as Popperian “themes” to eliminate the implication that he was the one who changed direction. There  are six themes  but  there are other ways to present to unity and coherence of the work and I want to find a way to  include them as well.

For example in Realism and the Aim of Science xxxv he wrote “It so happens that the real linchpin of my thought about human knowledge is fallibillism and the critical approach”.

In his lectures during the 1950s and the series of  papers in the 1960s that became Objective Knowledge it is clear that problem-solving is a central feature, in contrast with passive data collecting and the explication of concepts. That is spelled out in the four-stage schema, including the all-important process of testing and critical appraisal which leads to the emergence of deeper problems.

I want to mention the historical approach and also situational analysis which I see as the way to approach scientific and intellectual problems  as well as the explanation of human action in the social sciences.

I also want to note the contribution of colleagues, especially in relation to various of the themes:  Bartley and Miller on conjectural knowledge and non-justificationism, Jarvie on the institutional theme (the social turn), Agassi on metaphysics, Bartley, Munz, Radnitzky and Wachterhauser on the evolutionary approach, Shearmur on the institutional theme and his work on Popper’s classical liberalism (adjusting the picture of Popper as a social democrat).

Any other suggestions?   Gombrich on the institutional turn (his 1974 paper in the Schilpp volume), Watkins on indeterminism in the Schilpp volume?

This is some additional material on  Postscript to The Logic of Scientific Discovery for the Popper’s Progress appendix in a revised edition of the Popular Popper series of Guides.

While Logic der Forschung was being translated during the 1950s to become The Logic of Scientific Discovery (1959) Popper wrote a lot of new notes and appendices. These grew to the point where they became a whole book which was intended to appear in 1959, titled Postscript to The Logic of Scientific Discovery: After Twenty Years ( from 1934/5 to the mid 1950s).  Due to continuous revisions, other projects and a serious problem with Popper’s eyes, the publication date receded until in the late 1970s William W Bartley took on the final editing. In the meantime drafts, galley proofs and copies of the manuscript circulated among Popper’s students and colleagues at the London School of Economcs.

The Postscript finally emerged from Bartley’s editorial hands in three volumes during 1982 and 1983; Realism and the Aim of Science (Volume 1), The Open Universe: An Argument for Indeterminism (Volume 2) and Quantum Theory and the Schism in Physics (Volume 3). They contribute to Popper’s long campaign in support of realism, indeterminism and objectivism which in turn support human freedom, creativity and rationality.

The 1982 author’s Introduction to Realism and the Aim of Science responds briefly to two claims that have been frequently raised against Popper’s ideas in the three decades since the book was first written. The first is the idea that Kuhn provided a refutation or even a serious criticism of Popper’s ideas.  After the launch of The Structure of Scientific Revolutions Kuhn and a deal of forceful criticism he retracted most of  his interesting and radical views and adopted  a more realistic position, so Popper could write  “On the question of the significance of falsification for the history of science, Kuhn’s and my views coincide almost completely.” (xxxi) Kuhn himself wrote:

“Even in the developed sciences, there is an essential role for Sir Karl’s methodology. It is the strategy appropriate to those occasions when something goes wrong with normal science, when the discipline encounters crisis.” (Kuhn, 1970, 247).

A “crisis” is a situation where generally accepted theories are challenged, something that can happen at any time when scientists are alert, which is for more often than proponents of normal science realize as Firestein explained in How Ignorance Drives Science.

The second is the claim that Popper’s program was seriously undermined by the failure of his formal definition of verisimilitude. The answer is that it is often possible to demonstrate that one theory can be superior to another, that is to say nearer to the truth (in some sense, without claiming that there is some Terminus that can be eventually reached), and Popper provided two examples: the sequence of theories about the solar system  from Ptolemy to  Copernicus, to Kepler , to Newton and the  advances in ideas about heredity from  Darwin to Mendel to the double helix.

It seems that by the 1980s most philosophers had lost interest in Popper and they did not notice the decisive rejoinder to Kuhn at the start of  Realism and the Aim of Science and the theory of metaphysical research programs in Quantum Theory and the Schism in Physics.

Realism and the Aim of Science has two parts, the first treats inductivism, which Popper regarded as the basis of subjectivism and idealism , and the second attacks the subjective interpretation of the probability calculus.

Popper critically  reviewed  four aspects of inductivism;  the logical, methodological, epistemological and metaphysical.  In the course of that survey he explained how his theory of falsifiability responded to some central issues in epistemology and he restated the significance of falsifiability in demarcating scientific, non-scientific, pseudoscientific and metaphysical theories  from each other. He placed his ideas in the context of modern empiricism by engaging with the positions of Berkeley, Hume, Kant, Russell and Mach. He noted Bartley’s commentary on  “non-justificationism” and the way that Bartley placed this in the forefront of his exegesis of Popper’s “conjectural turn” from the mainstream focus on justificationism.

The second part of Realism demonstrates a significant development of his ideas about probability from The Logic of Scientific Discovery. The thrust is the same, to attack the subjectivist interpretation of the probability calculus and the belief that probability measures a subjective degree of ignorance. In The Logic he pursued his objective interpretation of the probability calculus using the frequency interpretation but in Realism he rejected the frequency interpretation and instead proposed his own propensity interpretation. This evolved from a theory of probability to become a whole cosmology – a world of propensities!

In his editor’s foreword Bartley pointed out the deep connection between the arguments in the first and second volumes “in their mutual concern with the freedom, creativity and rationality of man”.  The first addressed the way that non-justificationism (the conjectural theme) supports rationality refutes subjectivist and sceptical claims about the logical limits of criticism (hence the limits to rationality). The treatment of determinism in the second volume claims that our rationality is indeed limited with respect to the future growth of human knowledge  but this is a positive and not a negative because if this limit did not exist  then our exchange of arguments about our actions and policies would be meaningless (because what will be, will be, regardless of our arguments).

“Popper thus argues that human reason is unlimited with regard to criticism yet limited with regard to its powers of prediction; and shows that both the lack of limitation and the limitation are; in their respective places, necessary for  human rationality to exist at all”.

The Open Universe makes a distinction between two kinds of arguments for determinism, the scientific and the metaphysical. Contrary to those who make the case for indeterminism on the basis of modern physics,  Popper argues that classical physics need  not presuppose or imply determinism and more than quantum physics does. The systematic nature of his thinking comes through in the connection that can be traced between subjective interpretations of probability and the way that metaphysical determinism persists in quantum physics even while the physicist may resist the scientific form of determinism.

The four chapters are “Kinds of Determinism”, “’Scientific’ Determinism”, “TheCase for Indeterminism” and”Metaphysical Issues”.  The chapter on metaphysical issues describes the theory of propensities as a gain for science.

An Afterword and two especially interesting and important addenda are attached.  “Indeterminism is not enough: An afterword” originally appeared in the monthly magazine Encounter in April 1973. It was the first introduction for the educated public to Popper’s  new line of evolutionary thinking and the “three world” theory which he presented in a series of conference papers during the 1960s.

The first addendum is “Scientific reduction and the essential incompleteness of all science” is a rejoinder to all the over-optimistic scientists who have ever proclaimed that the “end  of  the road” is near, that science (usually physics) is on the verge of delivering  The Final Theory About Everything.  He pointed out that Godel’s incompleteness theorem of formal arithmetic provides a formal demolition of the “end of the road” aspiration, although he regarded that as “heavy argument against a comparatively weak position”.  Popper’s world (of propensities) is a world of emergent evolution, emergent novelty, where problems may be solved but in the process deeper problems appear.

“Nevertheless, the method of attempting reductions is most fruitful, not only because we learn a great deal by its partial successes, by partial reductions, but also because we learn from our partial failures, from the new problems which our failures reveal.” (162)

The second addendum  “Further remarks on reduction, 1981” begins with a fascinating account of the discovery of many new elements, starting with element 72, as a result of Bohr’s quantum theory of the periodic system of elements. This looked like an epic achievement in reducing chemistry to physics because the theory led to the discovery of new elements, and more than that, it led to the prediction of some of their optical properties and some properties of their chemical compounds.

“It was  a great moment in the history of matter. We felt, rightly, this was it: Bohr had hit rock bottom.” (164)

But soon the dream of reduction was dashed due to work by Soddy (1910), Thomson (1913), Aston (1919).

“And then came Urey’s bombshell, the discovery of heavy water, which meant that all the basic measurements of chemistry, the measurement of the atomic weights, were slightly wrong and had to be revised. Thus the rock bottom suddenly gave way: somehow Niels Bohr had built on a morass. But his edifice still stood.” (165)

The addendum finished with a reference to Prigogine ‘s (1980) work on thermodynamics which explored the way that open systems can defy the usual understanding of the law of increasing disorder in the universe, due to the increase of entropy. It seems that some systems can export entropy into their environment and increase rather than decrease their internal order.

“Prigogine’s work may be looked upon as a piece of exciting physicalist reduction, at least in the sense that it takes the first steps towards a physical understanding of the evolution of higher structures, which seems to be a fairly obvious aspect of the evolution of life on earth. It may thus open the way to understanding the reason why the creativeness of life does not contradict the laws of physics.” (174)

The theme of the third volume of the Postscript is the way that the Copenhagen interpretation of quantum physics has been influenced by unstated and uncriticised metaphysical assumptions, especially determinism, subjectivism and instrumentalism. Of course the Copenhagen people are scientific indeterminists but Popper argues that there is a metaphysical form of determinism that they have not eliminated from their thinking.

There are four chapters after a 1982 Preface and an Introduction. The Preface makes a case for a realistic and commonsense interpretation of quantum theory to overcome the crisis in physics which Popper attributes to two things, the intrusion of subjectivism and the “end of the road” idea that quantum theory has reached the complete and final truth. In the Introduction he argues for an interpretation of quantum physics without the observer and he sharply formulated thirteen thesis to challenge the Copenhagen interpretation of the observer as an integral part of the system.

In Chapter I, ‘Understanding quantum theory and its interpretations’ Popper updated his ideas from the formulations in The Logic of Scientific Discovery. He still maintained that the problem of interpreting quantum theory is bound up with the interpretation of probability theory, and he argued that the theory of propensities that he described in the first and second volumes of the Postscript should be applied to the interpretation of quantum theory, thus resolving the difficulties that arise in the Copenhagen interpretation.

Chapter II ‘The objectivity of quantum theory’ returned to the issue of the observer in the system and confronted the doctrine that experiments have to be interpreted with the observer, and especially the consciousness of the observer, as one of the variables. The discussion includes the nature of quantum jumps and the existence or non-existence of particles.

Chapter III attempts a resolution of the paradoxes of quantum theory, using the propensity interpretation of probability, applied to (1) the indeterminacy relations, (2) the expirement of Einstein, Podolsky and Rosen, and (3) the two-slit experiment.

The long fourth chapter is the Metaphysical Epilogue. This covers a lot of ground, starting with a brief statement of the theory of metaphysical research programs (below). He then ran through a series of ten research programs. First the block universe of Parmenides, then Atomism and Geometrization, followed by Essentialism and Potentialism (from Aristotle), then Renaissance Physics (Copernicus, Bruno, Kepler, Galileo), The Clockwork Theory (Hobbes, Descartes), Dynamism (Newton), Fields of Force (Faraday, Maxwell), Unified Field Theory (Riemann, Einstein, Schrodinger) and finally The Statistical Interpretation of Quantum Theory. After a discussion of schism, programs and metaphysical dreams he went on to indeterminism and the reduction of the wave packet and a model of a universe of propensities to account for the leading features of all the ten programs that he sketched previously. After touching on some open problems he concluded with some comments on the role of metaphysical systems and the possibility of a demarcation within metaphysics, between good and bad systems.

“The proper aspiration of a metaphysician…is to gather all the true aspects of the world (and not merely its scientific aspects) into a unifying picture which may enlighten him and others, and which may one day become part of a still more comprehensive picture, a better picture, a truer picture.”

Metaphysical Research Programs

Popper’s theory of MRPs flows from his theory that we should look at the history of a subject, and its current status, in terms of its problem situations.

“In science, problem situations are the result, as a rule, of three factors. One is the discovery of an inconsistency within the ruling theory. A second is the discovery of an inconsistency between theory and experiment – the experimental falsification of the theory. The third, and perhaps the most important one, is the relation between the theory and what may be called the “metaphysical research programme”.

“By raising the problems of explanation which the theory is designed to solve, the metaphysical research programme makes it possible to judge the success of the theory as an explanation. On the other hand, the critical discussion of the theory and its results may lead to a change in the research programme (usually an unconscious change, as the programme is often held unconsciously, and taken for granted), or to its replacement by another programme. These programmes are only occasionally discussed as such: more often, they are implicit in the theories and in the attitudes and judgements of the scientists.”

“I call these research programmes “metaphysical” also because they result from general views of the structure of the world and, at the same time, from general views of the problem situation in physical cosmology. I call them “research programmes” because they incorporate, together with a view of what the most pressing problems are, a general idea of what a satisfactory solution of these problems would look like.”

“A World of Propensities”, a slender 51 pages, was published in 1990. It contains two lectures that Popper delivered in his 87th and 88 years, A World of Propensities: Two New Views of Causality and Towards an Evolutionary Theory of Knowledge.

 The book “All Life Is Problem Solving” (1999) also contains the essay, “Towards an Evolutionary Theory of Knowledge”. This lecture is a classic of how to approach the topic of knowledge without getting tangled in the regress of chasing definitions. Open any dictionary on the word “knowledge”, you will find all sorts of circularity and assumptions that knowledge is primarily empirically derived. Popper’s starting point is a very simple proposition that animals can know something: that they can have knowledge. He elegantly proposes that knowledge is linked to expectations. These expectations express theories of reality. We as with all living things have propensities to guess reality based on largely unconscious hypotheses which both logically and psychologically precede observation. Popper’s association of knowledge with expectation, or guessing, is a breakthrough in clarity. Animals and plants carry what can be defined as unconscious guesses or theories, namely initially their genes and other molecular and physiological codes.

In “A World of Propensities” Popper recounts his debt to Alfred Tarski and his view of truth as a correspondence of a statement with the facts. It is a theory of objective truth that requires us to distinguish clearly between truth and certainty. Popper also recounts his rejection of probabilistic induction and how shocked he was when Carnap followed the probability of hypotheses line in “The Logical Foundations of Probability”(1950). “I felt as a father must feel whose son has joined the Moonies; though of course they did not exist in those days.”

Popper’s propensity theory is an objective interpretation of the theory of probability. Propensities, it is assumed, are not mere possibilities but are physical realities. They are as real as fields of forces and vice versa. Propensities in physics are properties of the whole physical situation. Propensities, like Newtonian attractive forces, are invisible, and, like them, they can act: they are actual, they are real. However, neither our physical world nor our physical theories are deterministic, even though of course many possibilities are excluded by the laws of nature and of probability: there are many zero propensities. The future is open. It is especially obvious in the evolution of life that the future was always open.

 Accidents and preferences.

“The theory of motives determining our actions, and the theory that these motives in their turn are motivated or caused or determined by earlier motives etc., seems, indeed, to be motivated – motivated by the wish to establish the ideology of determinism in human concerns. But with the introduction of propensities, the ideology of determinism evaporates. Past situations, whether physical or psychological or mixed, do not determine the future situation. Rather, they determine changing propensities that influence future situations without determining them in a unique way.

And all our experiences – including our wishes and our efforts – may contribute to the propensities, sometimes more and sometimes less, as the case may be. (In spite of the instability of the weather, my wishes do not contribute to ‘sunshine tomorrow’. But they can contribute a lot to my catching the flight from London to San Francisco.)

In all these cases the propensity theory allows us to work with an objective theory of probability. Quite apart from the fact that we do not know the future, the future is objectively not fixed. The future is open: objectively open. Only the past is fixed; it has been actualized and so it has gone. The present can be described as the continuing process of the actualization of propensities; or, more metaphorically, of the freezing or the crystallization of propensities. While the propensities actualize or realize themselves, they are continuing processes. When they have realized themselves, then they are no longer real processes. They freeze and so become past – and unreal. Changing propensities are objective processes, and they have nothing to do with our lack of knowledge; even though our lack of knowledge is, of course, very great, and even though a particular lapse may, of course, be an important part of the changing situation.”

Do we have an attack on fanaticism?

The argument in a nutshell:  (1) fanaticism feeds on “justificationism”,  that is the assumption  that everything depends on “justified true beliefs” that are revealed or supported by the correct authority; (2) The CR critique of  justificationism provides what Richard Hamming called an “attack” on the theories, traditions and practices that feed fanaticism.

Elsewhere I have talked about this in the language of “draining the swamp of unreason”.

This article shows how the little-known work of William W. Bartley has the potential to vastly increase the effectiveness of skeptical resistance to superstition and prejudice in their many forms and varieties. Creative problem solving and imaginative criticism is straitjacketed by the dogmatic ‘true belief’ framework of Western thought. This framework generates on the one hand true believers who insist that they have the truth in their grasp, on the other hand relativists and nihilists who think that truth and falsehood are indistinguishable. The framework can be cracked with the aid of ideas from Karl Popper and William W. Bartley to create an intellectual environment where imaginative criticism and the pursuit of knowledge will flourish. In this environment the swamp of unreason and prejudice may be drained, instead of merely being held back in one place while it spreads elsewhere.