The Fatal Split: Karl Popper and Ludwig von Mises

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Two divergent approaches to the social sciences and to liberalism

By John Saudino

6 September 2021

1 Preface

For some time now there has been interest on the part of some philosophers of science to reconcile Karl Popper and the Austrian School of Economics. Some of the work done to this end has entailed exploring the relationship between Popper and Hayek,[1] or contextualizing Popper’s interventionism[2] or resolving the “more apparent than real” contradictions between Popper’s philosophy of science and that of Ludwig von Mises.[3]

Some of this work, like that of Mark Notturno on Popper and Hayek, has sought to use Popper’s philosophy for a rational critique of the Austrian school. Others, either by reevaluating Popper or critically examining Mises and Popper, have endeavored to make Popper’s philosophy more compatible with to the Austrian School and hence to its laissez-faire doctrines.[4] The fact that there was barely any direct engagement between Popper and Mises places on those mediating between them considerable burdens of study and analysis. This begs the question: Why should a philosopher of science, Popperian or not, engage in such a difficult task?

I believe a general answer was given by Popper himself. In The Open Society and Its Enemies he summed up what he viewed as the very essence of the rational tradition with his often invoked exhortation, “I may be wrong and you may be right, and by an effort we may get nearer to the truth.”[5] Popper believed that critical discussion or the “intersubjectivity” among scientists was the only way for science to progress. However, for Popper, the need for such a discussion in 1944 is based on something more urgent than this.  It has to do with his desire for unity among all the proponents of the Open Society.  In a letter to F.A. Hayek Popper urged Hayek to reconsider his very strong rejection of interventionism in favor of Popper’s suggestion to create a “conscious liberal humanitarian” form thereof:

 “…if we say this, then, there is a hope of getting over the fatal split in the humanitarian camp and of uniting the vast majority of liberals and socialists…to work for this union is to-day the main task of us all, without exaggeration.”[6]

And again 77 years later it seems to me, with all the authoritarian enemies that are, once again, gathering against it, The Open Society[7] could use some unity among its friends. There are some bones to pick here, certainly, but, as Popper tried to point out to Hayek, those who strive for the same ideals against the same enemies, should fight on the same team. Methodologically and philosophically Popper and Mises represent two very distinct approaches to liberal democracy. Their views have rarely been compared critically. I hope doing so here will help to generate fruitful and important discussion.

2 Introduction

My thesis here is the following: 

In spite of their mutual concerns and the many important similarities between them, the remaining differences between Popper and Mises are quite significant once one examines their implications, and that these implications reveal problems of vital importance to social science and hence to policy decisions.  

Karl Popper and Ludwig von Mises, though roughly 20 years apart in age, were both products of the waning Habsburg empire and confronted with the problems it had to deal with in the interwar years in Vienna. They were both bona fide geniuses with enormous historical and philosophical knowledge. They also shared an uncanny ability to explicate philosophical doctrines in the history of ideas to reveal their profound impact on human affairs and civilization.

Strangely enough, although they knew each other and spent time in the same circles, they apparently never engaged each other in serious discussion[8]. Popper was invited to join the Mont Pelerin Society established by his friend and benefactor F.A. Hayek.[9] This organization was to play a leading role in the spread of free market thinktanks in Europe and in the USA.[10]  Mises became a member, joining his student F.A Hayek, Milton Friedman, and others as one of the founding members in 1947. The ideological differences between Mises and Popper were quite pronounced in this context. Popper, for reasons already given above, urged Hayek, unsuccessfully, to include liberal socialists[11] in the Mont Pelerin Society, suggesting that he invite, among others, Bertrand Russell and George Orwell.[12] Mises, on the other hand, famously stormed out of the opening discussion among the free-market economists shouting, “You are all a bunch of socialists!”.[13]

In spite of their different approaches to liberalism, however, there are, both in the realm of philosophy of science and in the realm of political philosophy, some striking points of agreement. Francesco Di Iorio has identified many of them. Both Mises and Popper largely agreed on the following: “the primacy[14] of theory compared to experience; the anti-instrumentalist or realist conception of science; that empirical theories rest on non-empirical presuppositions;[15] the idea that in both the natural sciences and the social sciences explanations are based on the determination of causes by general laws; the awareness of the incertitude of science; methodological individualism; the criticism of scientism, inductivism and holism in the social sciences.”[16]  I would add to this list their shared rejection of the following:  historicism, tribalism, monism/materialism, logical positivism,[17] polylogism/“the sociology of knowledge”[18] and, more importantly, their shared commitment to individual freedom.

Their rejection of scientism above requires an important caveat, though. For Mises and Hayek “scientism” meant the “slavish imitation of the method and language of science.”[19] For Popper, on the other hand, it meant “the aping of what is widely mistaken for the method of science.”[20] Popper was a proponent of the unity of scientific method and held that, as he understood them, the methods of the natural sciences and the social sciences were essentially the same, i.e. it was only because of the mistaken prejudice that the methods of the natural sciences must be inductivist, required essentialist methods and misconceptions regarding complexity, etc. that there was confusion.[21]

Popper’s continuing insistence on the “unity of method”[22] in spite of his intense and deferent engagement with Hayek, already suggests, in spite of all those many points of agreement, a difference, which we shall see, is much more than a mere nuance.

In the course of his investigation into “The Reconciliation of Apriorism and Fallibilism”[23] Iorio has crystalized at least three points on which Popper and Mises disagree: 1) the relationship between theory and experience 2) the nature of the rationality principle and 3) the foundations of methodological individualism.[24]

For the purpose of this article, I will tackle these issues in the order I have listed them here, the first two in some detail, the last only briefly. I will endeavor to show the foundations of these differences as well as their significance for the methodology of the theoretical social sciences.

3 Theory and Experience: Fallibilism vs Apriorism

3.1 The Twin Problems of Induction and Demarcation. Solutions and Implications

According to Popper the Two Fundamental Problems of the Theory of Knowledge[25] are the problems of induction and demarcation. Hume had shown that induction is logically impossible; there is no way of making content enlarging and truth preserving inferences from experience. Kant’s reformulation of “Hume’s Fork” also held that there were only two kinds of knowledge or truth statements: a-priori, analytical, necessary truth statements on the one prong of Hume’s fork and a posteriori, synthetic, contingent truth statements on the other prong of the fork. Apriori knowledge is analytic and certain because of the law of identity[26] but is merely tautological, not empirical. A posteriori knowledge is synthetic, contingent, but is empirical. The latter only gives us certain information of past events, not universal laws that would apply to the future. The first type gives us universally apriori valid truths, but they say nothing about the real world.[27]  This “analytic/synthetic dichotomy” was famously formulated by Einstein as follows:

“As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality.”

Expressed in more Popperian terms, it would be this:

“If science is about discovering natural laws that are universally valid and empirical, how is it possible if that which is universal is not empirical and that which is empirical is not universal?”

In trying to solve this problem of induction, Popper soon saw that the problem was inherently linked with another problem, demarcation, which for him and the logical positivists meant distinguishing between science and non-science.[28] This demarcation was of central importance both for Popper and for the logical positivists. This demarcation was accepted as part and parcel of the Viennese Late Enlightenment, Spätaufklärung,[29] as a reaction both by Popper and the positivists to the dominant tendencies in contemporary philosophy related to Romanticism, Hegelianism and the philosophy of Heidegger. After the catastrophe of The Great War it was of vital importance for these mathematicians, logicians, scientists and philosophers to rescue European thought from the depravity of irrationalism and idealist philosophy which represented nothing more than obscurantist mystification in their view, and which, as Popper was to point out in his magnum opus, was responsible for so much irrationality, brutality and war. Philosophy was to be the handmaiden of science, not mysticism.[30]  

3.1.1 The Vienna Circle: Logical Positivism

The philosophers of the Vienna circle were strict empiricists and took Hume’s fork seriously. If any statement is neither verifiable, that is to say it cannot be traced back to sensory input, nor true analytically, proven by math or logic, one must take it and “cast it into the flames” as Hume had suggested. The flames they cast such statements into was the bonfire upon which all “metaphysical” statements, which for them were nonsense, would be burned and dismissed as irrational and irrelevant. This formed the basis for the strongly empiricist school of thought, a branch of positivism,[31] they called logical positivism. The logical positivists believed that induction was the only foundation for empirical science and tried, in part, to deal with its limitations through probability calculus.[32] Thus their “solution” to the problem of induction was probability or some form of neutral monism[33] and their criterion for demarcation was verifiability.

3.1.2 Karl Popper: Critical Rationalism

Popper also took Hume seriously but the Popperian solution was quite different. He was not a positivist. He accepted Hume’s point on the logical problem of induction but thought that he was wrong regarding the pragmatic problem of induction. Hume pointed out that induction was impossible for logical reasons but accepted the notion that we could simply trust our habit of expecting the past to resemble the future. For Popper this meant accepting an “irrational epistemology”[34] because it was based merely on human habit, and is a form of what he called psychologism, which he also criticized in J.S. Mill.[35] Popper’s solution is to sacrifice certainty, which he believes is impossible in the sciences, for truth.  “The Truth”, which we can never know fully, can nonetheless be used as a regulatory principle. After studying Tarski, in a sort of epiphany, Popper realized he could maintain verisimilitude, or truth likeness, based on Tarski’s theory of truth, one based on the “the correspondence theory of truth”.[36] Thus critical rationalism preserves external realism and objectivity by retaining empiricism as a critical standard of truth, and at the same time is distinct from positivism because it views all knowledge unjustifiably by any authority and inherently uncertain.

His solution to the problem of induction was to proceed with deductive methods. A theory serves as a conjecture and the logical consequences of the theory are then deduced from it and then tested. Induction is not needed for the formation of theories. Popper held that theories cannot be verified, as the logical positivists insisted, but rather they can only be falsified. Using verification would lead to the kind of verification or confirmation bias that is typical of pseudoscience.[37] There is also an asymmetry between verification and falsification,[38] so his way of maintaining empiricism was to formulate all admissible theories so that they could in principle be falsified. This is Popper’s criterion for demarcation. Theories with the potential to be falsified are considered scientific because they can be refuted by experience. Anything that cannot be refuted by empirical tests is outside the purview of science, i.e. pseudoscience or metaphysics.

However, for Popper metaphysics and pseudoscience were not nonsense, as maintained by the logical positivists, because a rational discussion of either one could yield theories that contain falsifiable statements and hence falsifiable theories.[39] This greatly distinguishes critical rationalism from logical positivism. The key factor in preserving the objectivity of science is not induction in theory formation but testability. All theories remain only provisionally true even after they have passed severe tests; they are conjectures and are never justified or confirmed as true. However, a rational selection can be made among the unfalsified theories through a critical discussion among scientists.[40]

In spite of their differences, it was the aim of both the logical positivists and Popper to combat what they viewed to be the disastrous influence of German idealism and Romanticism, and to make philosophy and society more rational and scientific. Therefore they both applied a demarcation criterion that first and foremost distinguished broadly between what was science and what was not. This demarcation made sense because both sides believed that science was the quintessentially rational pursuit. They therefore advocate the essential “unity of method” of all the sciences, something Mises vehemently rejects. It was Popper’s conviction that the rationality inherent in science should also be applied to human society and that by doing so, social traditions and institutions, which for him must be open to rational criticism, could be reformed.[41]

3.1.3 Ludwig von Mises and Praxeology

Mises’ solution to the problems of induction and demarcation is radically different from that of logical positivism or critical rationalism. His response to the problem of induction is to adopt purely apriori methods. By starting with one self-evident premise “man acts”, he constructs theories through “logically unassailable ratiocination”[42] and applies them to his own science that he called praxeology, “the universally valid science of human action.”[43]

The advantage with apriorism is that the problem of induction is not even a factor; the theories are apodictically true, because they are not empirical observations but rather logical constructs, “in the last analysis, logic and the universally valid science of human action are one and the same.”[44]

Mises’ demarcation scheme consists of far more than the mere division between science and non-science. For him unified science is a “chimera”.[45] Every science has its own internal kind of logic and conceptual tools and methods that make it inapplicable to any other. The way in which praxeology and its related sciences are demarcated from one another is rather complicated. For him “the science of human action” stands outside the purview of other sciences. First off it stands between but separate from the logical sciences (math and logic) and the natural or empirical sciences; it is something intrinsically distinct from these two. It has two main branches; praxeology, which subsumes economics, and history, which has an entirely different epistemological status than praxeology such that it cannot provide any knowledge of regularities. History is “the collection and systematic arrangement of all the data and experience concerning human action.”[46] Both Popper and Mises reject historicism, the doctrine held by holists of both the right and the left that there are “historical laws” that allow us to predict the future.[47]

Mises, however, further demarcates history in other ways. From his praxeological point of view, there are many fields that can be viewed historically but only as far as the scientist excludes other clearly related fields. “There is ethnology and anthropology, as far as they are not part of biology, and there is psychology as far as it is neither physiology, nor epistemology nor philosophy. There is linguistics as far as it is neither logic nor physiology of speech”.[48]

There are other distinctions as well, but the Misesian demarcation that seems of most interest with regard to Popper, which is strikingly reflected above,[49] is the one that places an impenetrable wall between the social sciences, “the sciences of human action”, and the natural sciences. For him applying the methods of the natural sciences to the social sciences represents “scientism” and is a destructive methodological mistake typical of what he views to be one of economics’ most threatening foes, positivism.[50]

Even after reading a lot of his work, I was still quite puzzled by Mises’ complicated way of demarcating between sciences like this, until I took a closer look at the introduction of Human Action. The reason for this, at first baffling, set of Misesian demarcations is that, according to him, economics is a field that did not come into being until the 18th century and therefore does not fit into the logical structure of the sciences that were inherited from Ancient Greece. It is something completely new that “opened up to human science a domain previously inaccessible and never thought of…it conveyed knowledge which could be regarded neither as logic, mathematics, psychology, physics, nor biology.”[51] This new and distinct science was one that had profound and unprecedented implications for the study of society:

“Now it was learned that in the social realm too there is something operative which power and force are unable to alter and to which they must adjust themselves if they hope to achieve success, in precisely the same way as they must take into account the laws of nature.”[52]

He describes how the scope of economics radically expanded as a result of the debates between economists during the Methodenstreit. Modern subjectivist economics[53] “converted the theory of market prices into a general theory of human choices.”[54] Hence the naked study of exchange ratios and prices which Mises calls catallactics is too narrow for this new science and is subsumed into the overreaching science of praxeology that is the science of all human action, a kind of royal discipline of the social sciences.

 Mises’ solution to the twin problems of induction and demarcation imparts important advantages to his economic theory from the point of view of those who hold it.  Because its aprioristic construction circumvents the problem of induction by being purely logical and irrefutable and because it is so strategically demarcated as an independent science of its own, it is immune to attacks launched at it by a whole host of doctrines he believes are engaged in a concerted effort to destroy economics. “The system of economic thought must be built up in such a way that it is proof against any criticism on the part of irrationalism, historicism, panphysicalism, behaviorism, and all varieties of polylogism.”[55]

3.2 Fallibilism vs Apriorism: Truth vs. Certainty

Given the fact that, as I pointed out in my introduction, both Mises and Popper firmly reject all those doctrines in the above list of rogue “-isms”, it would seem that there is no real need to protect praxeology from a critical rationalist critique. However, one might ask, “Is such a critique even necessary?” “Would they not essentially agree with one another on most things anyway?” 

It is after all true that Mises and Popper share a common goal of preventing totalitarianism and many methodological doctrines such as a belief in the theory laden nature of observation, and many other tenets already mentioned.  However, as I stated above, there are indeed differences that I think are important.

The first has to do with the truth status of theories or rather, as Di Iorio puts it, with “the relationship between theory and experience”.[56] For Mises praxeology is unassailable and “universally valid” because of its aprioristic approach. It is a conception of science that sees science as a form of logic and as the way to establish 100% proven true theories. Popper, on the other hand, views all theories, even those that have been corroborated, to be only provisionally true. Mises insists that the natural sciences have “nothing to say” about the social sciences, aka praxeology. Popper insists that the methods of the natural sciences provide the basis for objective knowledge and, besides a few methodological considerations, are essentially the same in all sciences. Is there a way of reconciling these two positions?

3.2.1 Fallibilistic Apriorism?

One argument that has been made is that what Mises is practicing is a kind of “fallibilistic apriorism”.[57] One aspect of this argument deals with the idea that Mises himself uses the word a priori in at least two distinct senses. He takes his cue from Kant’s idea of innate categories of human thought and establishes the foundation of his science on one a priori valid premise, “man acts”, the fundamental axiom of praxeology. This premise fits all three of the aspects of the a priori prong of Hume’s fork; it is a priori (before any experience), analytic (logically valid by way of the law of identity), and necessary (irrefutably true). However, when Mises develops his theory further, according to this view, he is somehow able to overcome the analytic/synthetic dichotomy. The statements derived from the premise are a priori in a different sense. They are a priori (before the particular experience in question), synthetic (they reveal new knowledge); but are they necessary or contingent? If they are necessary, Mises is not a fallibilist. If they are contingent, that would mean that they could be wrong and Mises could be seen as a fallibilist.

The logical possibility of constructing a synthetic a priori theory of any kind is dubious in itself for a host of reasons the treatment of which would explode the scope of this article.[58] However, for the purpose of evaluating the truth status of Mises’ claims we can examine the arguments that have been given suggesting he is a fallibilist.

Francesco Di Iorio explores the possibility of a “Reconciliation of Apriorism and Fallibilism”[59] and cites Barry Smith as having proposed the theory of “fallibilistic apriorism”. Quoting page 7 of Human Action Di Iorio points out that Mises admits that “science does not give us absolute certainty.”[60] There are also other remarks regarding the “insufficiency of human effort”.[61] Later we learn that Mises asserts that when there is a conflict between a theory and the facts, “The disagreement between the theory and the facts of experience consequently forces us to think through the problems of the theory again.” This sounds rather fallibilistic in itself. However, Mises’ very next sentence reads, “But so long as a re-examination of the theory uncovers no errors in our thinking, we are not entitled to doubt its truth.”[62] Thus given the theorist’s conviction that his or her “thinking” is sound and has not been “refuted by discursive logic”, as Mises puts it, the theory must win out over any empirical test.

If one contrasts this rather weak admission of the possibility of error to Popper’s insistence on severe empirical tests and considers Mises’ multitude of statements over many years of writing regarding the unassailability of his aprioristic method, one cannot help but doubt that there is any genuine fallibilism in praxeology.

Further, if we examine one of the few places that Mises specifically referred to Popper in this regard, we find that he seems to reject fallibilism in the Popperian sense altogether:

“If one accepts the terminology of logical positivism and especially also that of Popper, a theory or hypothesis is “unscientific” if in principle it cannot be refuted by experience. Consequently, all a priori theories, including mathematics and praxeology, are “unscientific.” This is merely a verbal quibble. No serious man wastes his time in discussing such a terminological question. Praxeology and economics will retain their paramount significance for human life and action however people may classify and describe them.”[63]

It is rather curious here how Mises accuses Popper, of all people, of engaging in “a verbal quibble”; Popper was, on the contrary, the most powerful critic of such essentialist obsessions with the meanings of words.[64] In dismissing Popper’s fallibilism here out of hand Mises also completely ignores the important asymmetry between verification and falsification that distinguishes Popper from the logical positivists and from Hume.[65]

Fallibilism is not about reconstructing the scientist’s ratiocination, but rather about vigorously subjecting theories to severe empirical tests, and establishing methodological rules for falsification and the evaluation of theories.  It is a question of verisimilitude, of making sure theories are approaching the truth, that they actually have a connection to the facts, to the real world outside the mind in terms of external realism.[66]

Thus, fallibilism and apriorism seem to remain irreconcilable in light of this analysis. My own experience reading Mises and analyzing his demarcation scheme, apriorism and the manner in which a host of doctrines are caricatured and summarily dismissed at every turn tends to give me the impression that the constructing of the praxeology edifice resembles something like a philosophical chess game. Successive immunization strategies through which all possible criticism is cut off at the knees and basic assumptions continuously adjusted, so as to strategically cover the theory’s own tracks are employed all for the sake of the theory’s own unassailability.[67] This may be my own subjective impression, but on the whole it does not seem to me to be a constructive approach to social theory.

3.3       Conventionalism

There has been some work done to reinterpret his work in a way divergent from Mises’ own insistence on extreme apriorism. Alex Linsbichler of the University of Vienna has suggested that, in spite of Mises’ own statements to the contrary, praxeology can be reinterpreted as a kind of conventionalism.[68] This conventionalist twist was also explored by economist Natsuka Tokumaru.[69] This approach is, I believe, quite tenable and can serve to reconcile Mises with many contemporary economists skeptical of apriorism, but as far as methodology and truth claims are concerned, conventionalism does not do much to reconcile Mises and Popper, given Popper’s strong objections to the immunizing strategies of conventionalism.[70]

But does this conventionalist twist undermine the truth claim of Mises’ approach? Would it not contradict Di Iorio’s contention that scientific realism is shared by both philosophers? That depends what one means by realism.[71]  A philosophical debate on realism: Aristotelian realism, external realism, internal realism,[72] would be relevant to this discussion, but for the purpose of this article it is sufficient to compare the practical elements of the truth claims of Popper and Mises.

3.4 “Nihilistic Neo-positivism”[73] vs. “Empty Scholasticism”[74]

Yet another telling reference to Popper is given by Mises’ stridently apriorist disciple Murray Rothbard, who wrote a preface to Mises’ later masterpiece Theory and History, a book of great philosophical sophistication that demonstrates both agreements and disagreements between Mises and Popper. As Mises did above, Rothbard in his preface to the book likewise associates Popper with positivism and “scientism”. Rothbard criticizes Popper’s approach as diametrically opposed to that of Mises, condemning it as the “more nihilistic neopositivism[75] of Karl Popper” in which the scientist “can only ‘falsify’ or ‘not falsify’ a theory.”[76]

This use of the term “nihilistic” is revealing here. Mises himself invokes the term in a strident indictment of the enemies of economics in his introduction to Human Action:

“The radicalism of this wholesale condemnation of economics was very soon surpassed by a still more universal nihilism. From time immemorial men in thinking, speaking, and acting had taken the uniformity and immutability of the logical structure of the human mind as an unquestionable fact. All scientific inquiry was based on this assumption.”[77]

This indignant rebuke by Mises demonstrates his close affiliation with the tradition of continental rationalism and Aristotelian realism, with the tradition that sees science as an endeavor consisting of the construction of taxonomies and apodictically true axiomatic systems.

Popper shares some affinity with continental rationalism with regard to his acknowledgement of the theory laden nature of observation and the role of metaphysics in theory formation. However, his empiricism and methodological nominalism stand diametrically opposed to such an approach.[78] Popper expresses the contrast as follows:

“As a realist I look upon logic as the organon of criticism (rather than of proof)”[79]

Whether you view Mises as an extreme apriorist or conventionalist, it is clear that his conception of truth is quite different from that of Popper. In Objective Knowledge Popper posits three distinct versions of truth theory: 1) correspondence 2) coherence and 3) pragmatism.[80]

Mises as an apriorist could represent 2) or as a conventionalist represent 3) but only Popper can represent 1), the notion of truth as correspondence to the facts. This theory is based on Popper’s acceptance of Tarski and represents, I would contend, much more faithfully the idea of external realism, of verisimilitude, and objective truth.[81]

In spite of all the methodological and ideological points of agreement that exist between Popper and Mises, this difference, regarding the relationship between theory and reality, is significant. Without a genuine fallibilism, that is to say, without the deliberate subjecting of theories to severe empirical tests to falsify them and to critically evaluate them with competing theories,[82] something conspicuously lacking in Mises, we find that the truth status and thus the notions of what constitutes a satisfactory theory in the social sciences is quite different between them. Mises’ approach seems to me to be based on an outdated paradigm associated with medieval scholasticism that viewed the role of philosophy as providing apodictically proven true knowledge. As Kant points out in The Critique of Pure Reason rational argument devoid of any empirical content can be used consistently to arrive at completely contradictory conclusions or aporias. Hegel took Kant’s antinomies and simply accepted that logic is contradictory and formulated his “unity of opposites”, which resulted in the mysticism and “reinforced dogmatism” of his system.[83] Mises, on the other hand, seems to have simply ignored the problem to a certain extent, arguing from one an apriori premise as if only one rational conclusion to the chain of reasoning were possible, basing his science on the debunked notion of a synthetic apriori or, as suggested above, on an immunized conventionalism. Either way his system forms an insufficient basis for an empirical science because, in sharp contrast to Popper, it does not adequately employ experience as the critical standard of truth.

4 Objective vs. Subjective Rationality

Popper admired both Hayek and Mises very much. Hayek, who was instrumental in promoting Popper’s career, was wedged between Popper and Mises. His mind provided a living laboratory in which the opposing tendencies of apriorism and fallibilism, of interventionism and laissez-faire were fleshed out and combined with Hayek’s own ideas. I believe many of Hayek’s methodological shifts can be understood in this light.  In 1994 Popper gave a memorial lecture in honor of Hayek at the Cato Institute.[84] In speaking of Mises, Popper says the following:

“I admired him greatly. I wish to emphasize this point since both he and I were aware of a strong opposition between our views in the field of the theory of knowledge and methodology. I think Mises saw in me a dangerous opponent—perhaps one who had robbed him of the complete agreement of his greatest pupil, Hayek…he never really opened a discussion by direct criticism. Like myself, he appreciated that there was some common ground, and he knew that I had accepted his most fundamental theorems and that I greatly admired him for these. But he made it clear, by hints that I was a dangerous person—although I never criticized his views even to Hayek…however I have by now mentioned to several people the fact of my disagreement, without entering into critical arguments. So much for those distant days.”[85]

These remarks reveal quite a bit of the problem situation at hand when comparing Popper and Mises. What would induce Mises to see Popper, of all people, as a “dangerous person” in spite of his pronounced deference in avoiding criticism of his views even to Hayek?

A hint is given in the speech itself where Popper refers to Mises’ method as “subjective” and his own as “objective”. However, to really get to the bottom of the dispute of “those distant days” we need to look at a controversial lecture that Popper gave to Harvard economists on the 26th of February 1963 that was not published until 1994 entitled “Models Instruments and Truth”.[86]

The subtitle is “the status of the rationality principle in social science”. Here we see how Popper’s philosophy of science faces a head-on collision with praxeology. His lecture not only attacks the aprioristic foundation of Mises’ prime axiom “man acts”, but also advocates an objective formation of this rationality principle over the subjective principle of the – unnamed – Mises.

There are some economists and social scientists who hold the view that Popper’s version of the rationality principle in this lecture is “ambiguous and self-contradictory”[87] or even incoherent. Maurice Lagueux[88] and Mark Notturno,[89] however, provide what I view as compelling arguments as to why this is not the case.

4.1 Mises’ Subjective Rationality

Let us briefly consider the apriori fundamental axiom of Mises’ praxeology, “man acts”, which simultaneously forms both the ontological bedrock of his system and his rationality principle. This axiom is the starting point of his theory. He views it to be purely logical, non-empirical, hence necessarily true and neither verifiable nor falsifiable.  According to Mises this axiom is based on “the logical structure of the human mind”.[90] In other words, it is not possible for human minds to think differently about this axiom. The category of action is established as self-evident and utterly inseparable from the rationality principle, as he sees it. “Human action is necessarily always rational. The term rational action is therefore pleonastic and must be rejected as such.”[91]

This “necessity” is linked to yet another of Mises’ demarcations, namely the one between praxeology and “thymology”, the analysis of human values i.e. the ends of human action. This demarcation is important for the rationality principle of praxeology. Ends and values are not part of praxeology; “its object is means not ends.”[92] Thus for praxeology all human action, from the suicide bomber’s attack on a bus in search of 70 virgins, to the schizophrenic mother who drowns her children in the bathtub to save them from the Devil, is rational.[93] It is rational because the action of these individuals makes perfect rational sense, from their point of view. This subjective rationality could be seen as an outgrowth of the Austrian theory of subjective valuations.

This principle of the unity of action and rationality allows Mises to separate means from ends, which is important from the point of view of laissez-faire economists because it seeks to avoid any form of “paternalism” or tendency on the part of social scientists to judge or try to reform the values or goals of the participants in the market or their perceptions of what constitutes appropriate goals or rational beliefs. Economics is wertfrei, value freeas Mises insists.[94] However, this principle is also useful, as we shall see, if one is adamantly insistent on separating the natural sciences from the social sciences. The unity of action and rationality, combined with Mises’ “methodological singularism”[95] as a form of methodological individualism, forms part of the basis for his unyielding rejection of interventionism.

4.2 Popper’s Objective Rationality

Popper’s rationality principle is very different from that of Mises. It is a rejection of apriorism and of subjective rationality. For Popper rational action means acting adequately according to the logic of the given situation, i.e. objective rationality admits of the possibility of irrational action. “In my view, the idea of a social situation is the fundamental category of the methodology of the social sciences.”[96] Popper’s focus is to train the scientist’s eye not on the psychology or alleged psychological/genetic apriori derived from an innate “structure of the human mind” but rather on the situational logic. The rationality principle cannot be founded on intuitionism, a doctrine Popper adamantly rejects, or logic as Mises suggests, but is applied as an animating principle for theoretical models as an “empirical conjecture”.[97] Not only is this rationality principle not apodictically true; it is itself manifestly false.

There has been much consternation about Popper, the father of fallibilism and versimilitude, accepting a falsehood as part of his theory. These objections are clearly misguided because they do not grasp the sense in which Popper uses the word “false” here. The rationality principle is false because 1) it is manifestly evident that people do not always act rationally in any objective sense and 2) it is like any part of a model only an approximation of reality. Anyone who has used models either in the natural sciences or in the social sciences knows that models are only rough oversimplifications of reality.

The false empirical conjecture that people act appropriately according to the logic of the situation is partially immunized, however, for methodological purposes. Popper referred to this in the Poverty of Historicism as the “zero method”.[98] In his lecture to the Harvard economists he explained it as follows:

“…if a theory is tested and found faulty, then we have always to decide which of its various constituent parts we shall make accountable for its failure. My thesis is that it is sound methodological policy to decide not to make the rationality principle, but the rest of the theory—that is, the model—accountable.”[99]

This distinction between a model and its animating principle, which may be a natural law when the model is used in the natural sciences, but is here an empirical conjecture, should be clear to anyone working in the social sciences. Lagueux comes to the, I believe, correct conclusion that “Popper’s highly criticized ideas on the rationality principle, far from being a shameful part of his work, are rather the result of a shrewd though somewhat sketchily espoused analysis of the state of social sciences.”[100]

The differences between Popper and Mises on rationality do not stop here; Popper’s focus on situational logic rather than on the animating principle leads him to expand his notion of rationality. In a footnote to his lecture, he explains as follows:

“It seems to me now that there are at least three senses of ‘rationality’ (and accordingly of the ‘rationality principle’), all objective, yet differing with regard to the objectivity of the situation in which the agent is acting.”[101]

These different aspects of the rationality principle are (1) the situation as it actually was, (2) the situation as the agent saw it, and between these two (3) “the situation as the agent could (within the objective situation) have seen it, and perhaps ought to have seen it.”[102]  

This objective approach opens up completely new dimensions to the social sciences:

“It is further clear that the difference between (1) and the two other versions of the rationality principle will play a part in our understanding of action, especially in the historian’s attempt to explain failure, and that the difference between (2) and (3), will play a similar part…Moreover, if there is a clash between (2) and (3) then we may well say that the agent did not act rationally.”

Mises’ unity of action and rationality keeps praxeology doggedly fixed to only number (2) above and excludes the possibility of irrational action by simply declaring all human action to be ipso facto rational. Mises endeavors to shore up his fundamental axiom by insisting that it is purely logical. However, by justifying it as apriori valid on the basis of “the logical structure of the human mind” what he is trying to dress up as a logically necessary truism is rather an empirical conjecture about human nature. This, it seems to me, would indicate that Mises is engaging in a kind of psychologism or intuitionism doctrines that Popper, I believe, rightly criticizes as inadequate to the tasks of the science, be they natural or social.[103]  

5 Atomism vs. Institutionalism in Methodological Individualism

Mises’ construal of M.I. is once again a case of one aspect of praxeology being adjusted to fit into the larger framework of its demarcation scheme and rationality principle, and it is once again done to further immunize the theory. His doctrine of the unity of action and rationality leads to a methodological individualism that is more atomistic than Popper’s because it is fixated on maintaining the idea of the unquestionably purposeful and hence rational nature of human action:

“The We cannot act otherwise than each of them acting on his own behalf. They can either all act together in accord, or one of them can act for them all.”[104]

Mises further atomizes this version of M.I. into “Methodological Singularism.”[105]

Both Mises and Popper condemned holism; they rightly condemned the holist doctrine that there is some mystical “world spirit”, “general will” or “Volksgeist” active in society and hence insisted on methodological individualism, an understanding of society in terms of individual action. But this does not mean that the results of action are always intentional, especially when that action results from the interaction of many agents under particular institutional constraints.  The version of M.I. Mises prescribes above does not seem to allow for a further analysis of the interactions among the individuals, or the sources of their beliefs regarding appropriate action, or the divergence that exists between individual intentions and aggregate outcomes.

Di Iorio cites Di Nuoscio and maintains that “Mises’ apriorism gives a better foundation for methodological individualism than Popper’s rationality principle. His apriorism transforms rationality into a principle that is “necessarily true”. Doing otherwise would lead to an interpretation of human action in terms of “the deterministic effect of socio-cultural factors that exist independently of individuals and control their minds and decisions.”[106] As far as the apriori “foundation” is concerned, I hope that section 3 above has clarified the quite doubtful nature of Mises’ truth claim in this regard. As far as it being “better” in any way, one would have to ask, “better for whom and for what?”. To me this doctrine seems like little more than another immunizing strategy against rational criticism. It seems quite preposterous to base a theory of social science on denying the manifest truism that people’s “minds and decisions” are indeed to a considerable extent determined by “socio-cultural factors” To demonstrate this I need only to quote Mises himself with regard to “Individual man”, Mises writes the following:

“He does not himself create his ideas and standards of value; he borrows them from other people. His ideology is what his environment enjoins upon him…common man does not speculate about the great problems. With regard to them he relies upon other people’s authority, he behaves as ‘every decent fellow must behave’, he is like a sheep in the herd.”[107]

As we will see below, there is little doubt that Popper’s humanism would impel him to condemn such a pronouncement, but the point here is about rationality. Mises’ insistence on the identity of action and rationality seems irreconcilable with any analysis that can make sense of what he is here describing or of the possible unintended results of the intended action of such agents.  

Popper’s objective rationality principle, founded on the idea “of acting appropriately to the situation”,[108] and considered in the three distinct senses describe above, provides a much richer and more fruitful basis for methodological individualism. It reveals the problem situation from a more institutional level, that is to say in terms of the constraints out of which “the logic of the situation” is formed. Thus, it allows for an analysis of irrationalism, of failure, of institutional dysfunction. As Iorio points out it “allows us to distinguish between science and ideology in history.”[109] Both Popper and Hayek favored a “non-atomistic methodological individualism”.[110] Hence Popper’s approach allows us to engage more productively in what both Hayek and Popper acknowledged as the true aim of the social sciences:

“The characteristic problems of the social sciences arise only out of our wish to know the unintended consequences, and more especially the unwanted consequences which may arise if we do certain things.”[111]  

As I have explained above, the identity of action and rationality, with its fixation on intentionality is an atomistic version of methodological individualism that fails to achieve this task adequately.

6. Conclusion:

Besides the more metaphysical questions regarding the tenability of apriorism or synthetic apriorism or the relationship between formal logic and reality there are questions that are far more interesting for us to address that I would like to approach as follows:

The reason I have spent so much effort here on questions of objectivity and rationality is because I believe these issues are of vital importance for both the natural and the social sciences. In this regard Mises theory seems to me to be characterized by a severely dogmatic attitude. How can an untestable, immunized, apriori or conventionalist theory that “is established deductively and imposed on reality”[112] actually describe social reality as it actually is? As Mises himself admits, it is more accurate to say that it prescribes how the world is to be.[113]

This raises interesting questions that need to be addressed.

As liberals we need to ask ourselves: “what sort of world is it that is thus prescribed by this theory?”

Does the “necessity” of Mises prescriptions square with Popper’s dichotomy between nature and convention or his moral principle of critical dualism?[114]

To return briefly to rationality I would like to point out that for Popper rationality is much more than a mere academic question. In chapter 24 of The Open Society and its Enemies Karl Popper writes that “the conflict between rationalism and irrationalism has become the most important intellectual, and perhaps even moral, issue of our time”[115] That time was the time of the advancing forces of fascism and Stalinism, and his mission was to trace their roots and to defeat them once and for all. As here suggested, rationalism has a distinctively moral component. “rationalism is closely connected with the belief in the unity of mankind.”[116] Critical rationalism is non-justificationist and anti-authoritarian. Its source of objectivity is the intersubjectivity between rational individuals who realize that everyone has a point of view worth listening to.

These are some of the roots of Popper’s egalitarianism, the ethos of the Great Generation of Pericles in which the ideals of freedom and equality were seen as two sides of the same coin and not as intrinsically irreconcilable with one another.

Is it possible to square Mises with this ideal?

A stark contrast can be seen between Mises and Popper in the general attitude expressed by Mises toward “the common man”. A particularly poignant example of this is offered by his congratulatory letter to Ayn Rand on the occasion of the publication of her magnum opus Atlas Shrugged:

“You have the courage to tell the masses what no politician told them: you are inferior and all the improvements in your conditions that you simply take for granted you owe to the effort of men who are better than you.”[117]

I do not include this for the sake of its emotional impact but to point out that we have some pronounced philosophical differences here between Popper and Mises with regard to humanism:  Is it to be an elitist aristocratic doctrine of Aristotle’s “Magnanimous Man” or is it a Socratic, Christian egalitarianism doctrine?

I began this paper with an allusion to Popper’s notion of a “fatal split” among the friends of the Open Society in the face of its enemies. It is a split that seems to date roughly from the founding of the Mont Pelerin Society in 1947. It remains a baffling mystery to me why an organization so committed to freedom and so opposed to totalitarianism would not want to count the likes of Bertrand Russell and George Orwell in its ranks. The liberal camp at the time included many who, like Popper, had a strongly egalitarian and Social Democratic attitude. As Malachi Hacohen points out, in 1947 “Mises and Hayek’s libertarianism was unprecedented. They did not continue a liberal antisocialist tradition; they created it.”[118]

As far as the lowering of taxes, the virtual taboo on fiscal spending, and the general hostility toward government, the success of their neo-liberal crusade, it must be admitted, has been stunning. We need to ask ourselves, “What have been the results of the Reagan Thatcher ‘revolution’ their ideas facilitated”?

Does the extreme libertarian creed of the Misesian school in the United States envision anything like genuine popular sovereignty, or is it a regime of “natural masters and natural slaves” as Popper criticized in Plato?

Is liberalism something like Greek democracy or is it merely a concerted aristocratic defense against the depravity of “the bewildered herd”?

Is it true that the mixed economy that existed in the United States and England from 1945 till 1980 was unsustainable and because of its interventionism teetering on the edge of totalitarianism?

Is this also true for the European mixed economies of today?

What has been the effect of the dominance of the neo-liberal inspired Federalist Society on US jurisprudence?

What is the status of the “permanent legal framework” advocated by neo-liberals,  i.e. things like the “Citizens United” SCOTUS decision of 2010; has the doctrine that “corporations are people” and “money is speech” improved or damaged our institutions?

Is the so called “textualism” of this school based on the reading of a constitution written for an 18th century agrarian society really valid today?

Has not the rise of industrial capitalism, never known or considered by the Founding Fathers, completely changed the problem situation and hence the constitutional mechanisms necessary to prevent tyranny?

Is it true that the stagflation of the 1970’s “proved” the theories of the monetarists and the Austrians and “refuted” the Keynesians, or was it cause by the Arab oil embargo and the sudden rise in energy costs of 400%?

Is social engineering, even in Popper’s piecemeal form, “paternalistic” and part of a slippery slope towards statism?

Has the “deregulation”, union busting and the tax policy of the past 40 years had a significant role in rising inequality?

What are we to make of the rise in abject poverty, homelessness and mass incarceration over the past 40 years?

Is this rising inequality good for the stability of liberal democracy?

Does inequality pose a threat to freedom or do efforts to curb it pose a threat?

If we all agree that equality of outcomes is impossible and undesirable, does this rejection also include a rejection of the equality of opportunity?

How stable can a liberal democracy be in the face of a continuous diminution of its middle class?

And finally, why is the world leading democracy tearing itself into shreds before our eyes?

Something has gone terribly wrong.

These are only some of the problems that the friends of the open society, Social Democrats and laissez-faire liberals alike, need to address seriously if there is going to be any strengthening of the liberal cause in the face of current threats. I look forward to addressing them in the rational spirit and with an open mind with all those who care about the Open Society and its defense.

Bibliography

  1. Popper, Karl R., The Open Society and its Enemies, Vol. II&II, Princeton University Press, 1945/1971
  2. Popper, Karl R. Objective Knowledge: An Evolutionary Approach, Oxford at the Clarendon Press, 1979.
  3. Popper, Karl R., The Poverty of Historicism, Routledge 1957/2002
  4. Popper, Karl R. Conjectures and Refutations: The Growth of Scientific Knowledge, BASIC BOOKSPublishers; New York London, 1962
  5. Popper, Karl R, The Myth of the Framework: in defense of science and rationality, edited by Mark Notturno, Routledge, London and New York, 1994
  6. Popper, Karl R, The Logic of Scientific Discovery, Routledge, 1935/1992
  7. Popper, Karl R, After the Open Society, edited by Jeremy Shearmur and Piers Norris Turner, Routledge London and New York, 2008
  8. Mises, Ludwig von, Human Action, Liberty Fund Indianapolis, 2007
  9. Mises, Ludwig von, Epistemological Problems of Economics, D. Van Nostrand Company, Inc., 1960
  10. Mises, Ludwig von, The Ultimate Foundations of Economic Science, D. Van Nostrand Company, Inc., 1962
  11. Mises, Ludwig von, Theory and History, Yale University Press, 1957
  12. Mises, Ludwig von, “Letter to Ayn Rand”, Mises Institute,  January 23, 1958
  13. Francesco Di Iorio, Cognitive Autonomy and Methodological Individualism: The Interpretative Foundations of Social Life, Springer International Publishing Switzerland, 2015
  14. Shearmur, Jeremy, The Political Thought of Karl Popper, Routledge, London New York, 1996
  15. Notturno, Mark, Hayek and Popper: On Rationality, Economism, and Democracy, Routledge London, New York, 2015
  16. Hacohen, Malachi Haim, Karl Popper-The Formative Years, 1902-1945, Cambridge University Press, 2000
  17. Magee, Bryan, Popper, Fontana Press, 1973
  18. Stadler, Friedrich „Spätaufklärung und Sozialdemokratie in Wien 1918–1938. Soziologisches und Ideologisches zur Spätaufklärung in Österreich“, Aufbruch und Untergang. Österreichische Kultur zwischen 1918 und 1938, Europa Verlag, 1981
  19. MacLean, Nancy, Democracy in Chains, Penguin Random House, 2017
  20. Champion Rafe, „Making Sense of Popper“, Mises Institute, 2001
  21. Jackson, Ben, “AT THE ORIGINS OF NEO-LIBERALISM: the free economy and the strong state, 1930 –1947”, The Historical Journal, 53, 1 (2010), Oxford University Press
  22. Rockwell Jr, Llewellyn H., “Keynote Address”, Ludwig von Mises Institute, Auburn Alabama, September 15th 1998
  23. Hayek, F.A. v, “Scientism and the Study of Society: Part I”, Economica 9(35), 1942
  24. Reichenbach, Hans, Experience and Prediction: An Analysis of the Foundations and the Structure of Knowledge 1938
  25. Linbichler, Alexander, „Austrian Economics without Extreme Apriorism”, Springer, 12 March 2019
  26. Putnam, Hilary “Realism and Reason” Proceedings and Addresses of the American Philosophical Association, Vol. 50, No. 6, Aug 1977
  27. Lagueux, Maurice “Popper and the Rationality Principle”, Karl Popper: A Centenary Assessment, Volume III, Aldershot, Ashgate Publishing Ltd, 2006. pp. 197-208

Notturno, Mark, “Truth, Rationality, and the Situation”, 2013

[1] Notturo, Mark, Hayek and Popper: On Rationality, Economism, and Democracy, Routledge London, New York, 2015

[2]Shearmur, Jeremy, The Political Thought of Karl Popper, Routledge, London New York, 1996

[3]Di Iorio, Francesco, Cognitive Autonomy and Methodological Individualism: The Interpretative Foundations of Social Life, Springer International Publishing Switzerland, 2015, pp. 149-179

[4] Rafe Champion, “Making Sense of Popper”, Mises Insitute, 2001

[5] Popper, Karl R., The Open Society and its Enemies, Vol. II, Princeton University Press, 1945/1971, p.225

[6] Notturno, (2015) p. 25, Popper Archive 305.13

[7] Here, of course I refer to liberal democracy, not to Popper’s book

[8] Di Iroio (2017) pp. 149-176

[9] Hayek was instrumental in getting The Open Society and Its Enemies published in England and in getting Popper his professorship a LSE

[10] MacLean, Nancy, Democracy in Chains, Penguin Random House, 2017

[11] Ben Jackson, “AT THE ORIGINS OF NEO-LIBERALISM: the free economy and the strong state, 1930 –1947”, The Historical Journal, 53, 1 (2010), Oxford University Press, pp. 129–151

[12] Shearmur  (1996) p. 30

[13]  Rockwell Jr, Llewellyn H.., Keynote Address, Ludwig von Mises Institute, Auburn Alabama, September 15th 1998

[14] I agree with De Iroio here to the extent that “primary” is understood in the chronological sense. Though Popper held that theories are formulated without using induction, he insisted that these conjectures were to then be tested by means of severe empirical tests. (see Ch. 10 Conjectures and Refutations)

[15] This is generally correct. There is, however, a significant exception regarding the rationality principle. See “Models Instruments and Truth”, explored in section 4.2 below.

[16] Francesco Di Iroio, Cognitive Autonomy and Methodological Individualism The Interpretative Foundations of Social Life, Springer International Publishing Switzerland 2015, p. 151

[17] As has been pointed out by several authors, Mises misunderstood some aspects of Popper and unduly associated him with the “positivism”.

[18] See Popper The Open Society and Its Enemies, pp. 212-223, Mises Human Action, pp. 75-89, and The Ultimate Foundations of Economic Science, p. 130

[19] Hayek, F.A. v,  “Scientism and the Study of Society: Part I”, Economica 9(35), 1942, pp. 267-291

[20] Popper, Karl R. Objective Knowledge: An Evolutionary Approach Oxford at the Clarendon Press, 1979. p.185.

[21] Karl Popper, The Poverty of Historicism, Routledge 1957/2002, pp. 120-132

[22] Ibid, p. 120

[23] Di Iroio (2015) p. 151

[24] Ibid, pp. 151-176

[25] Die Beiden Grundprobleme der Erkenntnistheorie, Popper’s first book, written mostly in 1930-1932 though it was published long afterwards.

[26] In logic, the law of identity states that each thing is identical with itself. It is the first of the three laws of thought, along with the law of noncontradiction, and the law of excluded middle. Its symbolic formulation is A=A. It is true logically, not psychologically, and as such is distinct from any genetic or psychological apriori postulated as an innate structure of the human mind.

[27] What is meant here by analytic are statements that are true by definition i.e. by the law of identity “A is A”. Examples would be analytic statements like “A bald man is a man”, “A bachelor is unmarried” or the statements of arithmetic, like 7+5=12, which by means of analysis of both sides turns out to be nothing more than a tautology i.e. 1+1+1=1+1+1. That is to say such statements are not synthetic and do not yield any new knowledge.

[28] Malachi Haim Hacohen, Karl Popper-The Formative Years, 1902-1945, Cambridge University Press, 2000, pp. 195-208

[29] Friedrich Stadler, „Spätaufklärung und Sozialdemokratie in Wien 1918–1938. Soziologisches und Ideologisches zur Spätaufklärung in Österreich“, Aufbruch und Untergang. Österreichische Kultur zwischen 1918 und 1938, Europa Verlag, 1981, pp. 441-473

[30] See Wiener Kreis Texte zur wissenschaftlichen Weltauffassung von Rudolf Carnap, Otto Neurath, Moritz Schlick, Philipp Frank, Hans Hahn, Karl Menger, Edgar Zilsel und Gustav Bergmann Herausgegeben von Michael Stöltzner und Thomas Uebel

[31] Positivism: positivism is used to mean many different things. Mises traces its origins to Comte and views it primarily as the, for him, mistaken doctrine of the “unity of science”. Popper, who advocated the unity of science was, at the same time, an opponent of logical positivism. These misunderstandings were to cause confusion not only between Mises and Popper, but between Popper and the Frankfurter Schule during the so called “Positivismus Streit”. 

[32] Reichenbach, Hans, Experience and Prediction: An Analysis of the Foundations and the Structure of Knowledge 1938

[33] This was the position of Ernst Mach, rejected by Mises, Popper, and V.I. Lenin. (Hacohen (2000) pp. 56-57)

[34] Karl Popper, Objective Knowledge, Oxford at the Clarendon Press, 1972, p. 7

[35] Popper, O.S., Vol. 2 „The Autonomy of Sociology “, pp. 89-99

[36] Karl Popper Conjectures and Refutations: The Growth of Scientific Knowledge, BASIC BOOKSPublishers; New York London, 1962 pp. 219-228

[37] Examples of these for Popper were Freudian psychoanalysis and Marxism. The key factor here is that because a pseudoscientific theory explains too much it is highly susceptible to confirmation bias.

[38] Popper, Objective Knowledge, an evolutionary approach, Oxford at the Clarendon Press, 1972, p. 7

[39] Bryan Magee, Popper, Fontana Press, 1973, pp. 45-46

[40] Popper, Conjectures and Refutations, Ch 10 „Truth Rationality and the Growth of Scientific Knowledge”, pp. 120-135

[41] Ibid

[42]Mises, Ludwig von, Human Action, Liberty Fund Indianapolis, 2007, pp. 67 & 991

[43] Mises, Ludwig von, Epistemological Problems of Economics, D. Van Nostrand Company, Inc., 1960 p. 13

[44] Ibid, p. 13

[45] Mises, Ludwig von, The Ultimate Foundations of Economic Science D. Van Nostrand Company, Inc., 1962 p. 38

[46] Mises, Human Action, pp. 30-32

[47] See Ludwig von Mises, Theory and History, Yale University Press, 1957, pp. 198-234 and Popper The Open Society and The Poverty of Historicism.

[48] Mises, Human Action, p. 30 My point here is that all these fields dovetail with problems involved in the natural sciences and restricting them in this way by such an arbitrary demarcation scheme can hardly facilitate their solution. Popper’s approach is to say that we are students of problem situations not demarcated fields of study.

[49] Notice how all those sciences above have the aspects integral to them that are based on the natural sciences or on logic surgically removed so as to make them fit into Mises’ praxeological framework.

[50] Mises, Ultimate Foundations, „Positivism and Crisis of Western Civilization” pp. 125-132

[51] Mises, Human Action, p. 1

[52] Mises, Epistemological Problems of Economics (1960), p. 3

[53] He means here, of course, the Austrian School as a paradigm as to what economics really is in his view.

[54] Mises, Human Action, p.3

[55] Mises, Human Action, p.7

[56] Di Iroio (2015) p. 151

[57] Di Iroio (2015)

[58] See for example the arguments made by Bertrand Russell in The Problems of Philosophy and The History of Western Philosophy

[59] Di Iroio (2015) p. 151

[60] Ibid, p. 158

[61] Ibid, p. 159

[62] Ibid, p. 159

[63] Mises Ultimate Foundations of Economic Science, p. 70

[64] Karl Popper, The Open Society and Its Enemies Vol II, Ch 11 “The Aristotelian Roots of Hegelianism” pp. 1-26

[65] Karl Popper, Objective Knowledge (1972) p. 7

[66] See note 72

[67] Compare this to Popper’s principle of stating another’s theory as strongly as possible before refuting it.

[68]Alexander Linbichler, „Austrian Economics without Extreme Apriorism”, Springer, 12 March 2019

[69] Natsuka Tokumaru, “Popper’s Analysis of the Problems of Induction and Demarcation and Mises’ Justification of the Theoretical Social Sciences” Rethinking Popper, Boston Studies in the Philosophy of Science, Springer, 2009

[70] Karl Popper, The Logic of Scientific Discovery, Routledge, 1935/1992, p. 59

[71] According to Jörge Guido Hülsmann, who wrote an introduction for a Mises work in 2002, Mises stood in the tradition of “Aristotelian realism” that was still significant in Catholic Austria at the time. See: Epistemological Problems of Economics, Third Edition, Ludwig von Mises Institute, Auburn Alabama, 2003 pp li-lii

[72] See Putnam, Hilary “Realism and Reason” Proceedings and Addresses of the American Philosophical Association, Vol. 50, No. 6, Aug 1977,  pp. 483-498

[73] See note 71

[74] Karl Popper, The Open Society and Its Enemies Vol II, p. 10

[75] My italics (otherwise always from the original)

[76] Mises, Ludwig von, Theory and History, Yale University Press, 1957, p. xv

[77] Mises, Ludwig von, Human Action, p. 4

[78] Karl Popper, Conjectures and Refutations, Ch. 10 “Truth Rationality and the Growth of Scientific Knowledge”,

[79] Karl Popper, Objective Knowledge, p. 318

[80] Karl Popper, Objective Knowledge, Oxford at the Clarion Press, 1972, p. 308

[81] Ibid

[82] Mises does speak a lot about other theories but, as it seems to me, only as strawmen caricatures of pernicious “-isms” to be knocked down like dominos by his unassailable apriori juggernaut.  Compare this to Popper’s consistent habit of first presenting the doctrine he is refuting in the best light possible, before systematically refuting it fairly. And (with the notable exception of Hegel) he does so with no personal attacks or accusations of malice.  Mises here, by comparison, seems to me to be atrociously dogmatic.

[83] See “What is Dialectic”, by Karl Popper, Conjectures and Refutations

[84] Cato Institute, established in 1974 by Charles Koch, is one of the many Koch financed free market think tanks inspired by the Mont Pèlerin Society.

[85] Karl Popper, After the Open Society, edited by Jeremy Shearmur and Piers Norris Turner, Routledge London and New York, 2008, pp. 402-410

[86] Karl Popper, The Myth of the Framework: in defense of science and rationality, edited by Mark Notturno, Routledge London and New York, 1994, pp. 154-208

[87] Di Iroio, p. 152

[88] Lagueux, Maurice “Popper and the Rationality Principle”, Karl Popper : A Centenary Assessment, Volume III, Aldershot, Ashgate Publishing Ltd, 2006. pp. 197-208

[89] Notturno, Mark, “Truth, Rationality, and the Situation”, 2013

[90] Mises, Human Action, p. 25

[91] Ibid p. 19

[92] Ibid, p. 21

[93] Mises’ own example: “the unconscious and apparently senseless behavior of the neurotic and the psychopath.” Mises, Epistemological Problems of Economics, p. 34

[94] Ibid, pp. 19-22

[95] Ibid, p. 44

[96] Karl Popper, The Myth of the Framework, p. 166

[97] Ibid, p. 177

[98] Karl Popper, The Poverty of Historicism, p. 141

[99] Ibid, p. 177

[100] Lagueux, p. 208

[101] Karl Popper, The Myth of the Framework, p. 183

[102] Ibid, p. 183

[103] See: O.S. Vol. II Ch. 14 pp. 89-99, and The Myth of the Framework, pp. 168-169

[104] Mises, Human Action, p. 44

[105] Ibid, p. 45

[106] Di Iroio, (2015) p. 154

[107] Mises, Human Action, p. 46

[108] Karl Popper, The Myth of the Framework, p. 169

[109] Di Iroio, p. 173

[110] Di Iroio, p. xv

[111] Popper, C&R, “Toward a Rational Theory of Tradition”, p. 124, See also regarding Hayek, Di Iroio, p. 3

[112] Di Iroio, p 159

[113] See note 52 about how politics is “forced” to take the results of praxeology seriously. This leads to what Popper called “The Oedipus Effect”. K. Popper, The Poverty of Historicism pp. 13-14

[114] See O.S. Vol I, Ch. 5

[115] Popper, O.S., p. 224

[116] Ibid, p. 232

[117] Mises, Ludwig von, “Letter to Ayn Rand”, Mises Institute,  January 23, 1958

[118] Hacohen, p. 477

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