 And now it gives me a great pleasure to introduce our Mises Memorial Lecturer, Renaud Fillieu. Renaud is Professor of Sociology at the University of Lille in France. He first studied the natural sciences and received an engineering degree from the Ecole Centrale de Lyon. He then went on to study philosophy, sociology, and economics, and received graduate degrees in those fields, and then a PhD in sociology from the Sorbonne in Paris. He has done extensive research and very, very good research, and actually cutting-edge research, and teaching in Austrian economics, and has recently published a book in French that introduces the main techniques of the school to the French audiences. Currently, he's working on Austrian macroeconomics as well as price theory and epistemology, a true Renaissance man, Renaud. So it's difficult for me to express with words how honored I am to have the opportunity to give this 2012 Ludwig von Mises Memorial Lecture. So I wish to thank Professor Joe Salerno, of course, for the invitation, all the staff here at the Mises Institute, for the flawless organization, and Professor Guido Hürsmann for his support. von Mises, von Mises is the economist I most admire, as is probably also the case for many people in this room. And he fully deserves our admiration. As an outstanding scientist, a great epistemologist, and a leading fighter for liberty. And in this lecture, I want to pay tribute to the depth and relevance of his conception of theoretical social science as praxeology. Misesian praxeology rests upon two main pillars, first, the concept of action, and second, the a prioristic character of the theories of human action. But when he developed these insights, von Mises had mainly economic science in mind, and that's perfectly understandable. Now, I would like to illustrate his principles of action and of a priorism with the help of another branch of social science, namely the sociology of delinquency. And this survey will offer an unusual, but also, I hope, an instructive perspective on the foundation of social sciences as elaborated by von Mises. The title of von Mises' greatest treatise, Human Action, clearly indicates the foremost importance that he attached to the concept of action. And his whole theoretical and epistemological edifice is built upon this key concept. There are also many pages to his presentation. His starting point is the definition of action as a conscious or purposeful behavior, and he then deduces the main components implied in this concept. So I will review them very briefly. Beginning by ends and means, the two most basic elements of a theory of action. Causality, the relationship between ends and means implies the category of causality. The means, at the very least, are causes and the ends are effects. Rationality, an action is necessarily rational in the sense that it's always adapted to the end pursued on account of the personal knowledge of the actor. But the choice between ends, on the other hand, is a value judgment that specifically belongs to the acting person and is neither rational nor irrational. Scale of values. So the ends envisioned by an actor can be crudely materialistic or highly refined, but whatever their concrete content, their value or importance for the acting person is purely subjective and they are ranked along a scale that is ordinal, no measure or calculation of subjective values as possible. Then we have imputation. The means of an action only play an instrumental role in bringing about a chosen end. The value is derivative, it's imputed or ascribed to them from the value of end. Profit, psychic profit or loss. An action, if successful, will bring a subjective or psychic profit, a non-measurable but positive difference between the value of the end reached and the value of the end foregone. And if the action is unsuccessful, there's a psychic loss. Then we have time. An action necessarily takes place in time. Its aim is always set in the future since the present cannot be changed. Uncertainty. Action also implies change and uncertainty. If the future was certain, no action could possibly change it. There would be no role for acting. Now, in the 1920s and 1930s, Von Mises was very busy laying down the foundations for theory and epistemology of action. But during these same decades, sociologists and criminologists were developing theories in which the core concept was not action but rather culture. Modern criminology or sociology of delinquency appeared in the 1920s with the classic treatise by Edwin Sutherland, who is considered at the most influential criminologist of the 20th century. Born in 1883 was two years younger than Von Mises, so they both belong to the same generation. And Sutherland developed a famous cultural theory according to which criminal behavior is explained by the antisocial or pro-delinquency value system held by the criminal. More specifically, his theory rests upon two main principles. First, a learning principle, very simple. Delinquency or criminality is learned. This learning is a socialization process that takes place in small and intimate groups where members mainly learn two things, criminal techniques and pro-delinquency values. This idea of learning may seem overly simplistic but it was very important because it broke with the genetic theories of criminality developed in the 19th century by the positivists, César Elombroso and his famous born criminal. The second principle of this cultural criminology is called differential association. So here each individual belongs to some groups that favor conventional or low abiding behavior such as family, for instance, and may also belong to groups that favor antisocial or delinquent behavior such as groups of young delinquent peers. So the individual, so explained Sutherland, is confronted to contradictory or conflicting influences. And if antisocial values predominate around the individual, then he will become delinquent. And if conventional or pro-social values predominant, then he will comply with the law. And on a more general level, this explanation belongs to the cultural spreading that was developed by the first Chicago School of Sociology and which uses the idea of cultural conflict in order to account for the pathologies, including crime, of course, of the great American cities in the first decades of the 20th century. In the 1950s, two criminologists, Sykes and Madzah, provided one of the first convincing criticisms of this culturalist criminology. They showed that criminals or delinquents, in fact, do not have a set of values different from that of the general population. And they came to this conclusion through an investigation of the arguments used by the criminals themselves when they tried to justify their own illegal actions in court. And they observed that these offenders do not challenge the conventional value system. Rather, they use what these authors famously called neutralization techniques that help them to excuse their own behavior. For instance, they use the technique of the denial of responsibility. They justify, try to justify their illegal behavior by saying that they were pushed by an overwhelming force because they were drunk or needing drug or angered and so on. Now, what's very interesting here is that in all these kinds of arguments used by the offenders themselves, the conventional system of moral and legal norms is implicitly taken for granted. It's not criticized, it's not attacked. It is acknowledged and circumvented. So even if the delinquents have specific subcultures, those are not directly opposed to the conventional and usual morals prevalent in society. Criminals, in their own words, are not committed to a broad delinquency system of values. The culturalist explanation by Sutherland is totally contradicted by these observations. And also, the theoretical question of the cause of delinquency now drastically changes. Sutherland tried to answer the question, how do some people acquire an antisocial value system that turns them into criminals? But now the question becomes more subtle. Why do some people break the moral and legal rules to which they otherwise believe, even if not very strongly? And at this point, the society of delinquency is ready to take a praxeological turn that is to some extent similar to the subjectivist revolution that took place in economics at the end of the 19th century. And indeed, once the culturalist approach is discarded, the Misesian conception of action becomes highly relevant. And there are two reasons why this is so. In the culturalist approach, delinquency is an end in itself. Breaking the law is valued as such. Now, praxeology has nothing to say about ends and valued judgments. In the words of Van Mises, its object is means, not ends. It does not seek to explain, for instance, why some people choose asceticism, while others choose hedonism, why some people enjoy refined pleasures, while other people enjoy crude pleasures, and so on and so forth. So if the difference between criminals and non-criminals was their respective value systems, then praxeology would not have much to say about criminality and maybe nothing at all. The question, why do some people choose delinquency would be similar to the question, why do some people enjoy classical music? But if the moral values are more or less the same, they cannot by themselves alone explain why an individual commits a criminal act and another one in similar circumstances does not. The difference between criminality and non-criminality essentially becomes a choice of means, not of ends. And to that extent, delinquent acts are perfectly legitimate object of a praxeological analysis. Quebec criminologist Maurice Cusson has consistently followed this line of analysis. He has shown that delinquent action indeed follows the same kinds of ends as low abiding action, such as the search for wealth, prestige, power. The difference is that the means are obtained through theft, fraud, or illegal physical violence. There's a second reason why sociology of delinquency was really in the 50s to take a praxeological turn and break with culturalism. The culturalist approach rests upon a very naive conception of the relationship between culture and behavior. Behavior is supposed to follow the rules prescribed by the culture or subculture in which the individual has been socialized. And if I can use this metaphor, culture is conceived as a computer program and the individual supposedly follows the cultural moral code just like a computer follows the steps of a program. Now, as we have seen, offenders believe in the conventional moral code, even if not very strongly, of course, but their behavior more or less often violates this code nonetheless. And in the culturalist framework, this situation is paradoxical and very difficult to account for. In the Misesian framework, on the other hand, the explanation is straightforward. Even if a person is reluctant for moral reasons to break the law, she will choose an illegal act if it brings a higher psychic profit than the alternative legal acts. Let's suppose that an individual would prefer everything else equal to choose legitimate means rather than illegal means in order to reach his ends. In the context of a specific decision, he can nonetheless choose illegal means for the simple reason that they allow him to reach an end that is sufficiently high on his value scale. It is thus very easy to account for the common sense observation that people sometimes break their own moral code. And to sum up here, the culturalist approach is plagued by a paradox. If an individual has been socialized in a culture, how could he possibly act against the rules prescribed by this culture? And this paradox completely disappears when we use the basic proxological concepts, ends, means, and psychic profit. The proxological solution to this culturalist paradox is a bit reminiscent of the marginalist solution to the paradox of value in economics. After this criticism of this critic of culturalism, the next significant theory developed in the field of sociology of delinquency is the theory of social control. This theory clearly belongs, as I will show, to the proxological paradigm framework. Very briefly, this theory explains why individuals commit more or less serious delinquent acts by the fact that they are bound to society is weak or broken. Now, the expression, born to society, is not very misasian, to say the least. It seems to imply a holistic conception of society that von Mises forcefully criticized. But society here is not at all conceived as a separate entity that exists above and beyond the individual. And I'm going to show that, in fact, social control theory can easily be expressed in a proxological language. Let's follow the presentation offered by one of the most prominent exponents of social control theory and a great sociologist, the American Travis Hershey. In his well-known book, Causes of Delinquency, he explains that the bonds to society, mainly consist in the attachment to others and the commitment to conventional lines of action. Both of these elements have a straightforward proxological interpretation. The attachment to others, to family, to friends, to friends, to peers, to coworkers, and so on, is the fact to care about them, to be sensitive to their needs. And in terms of action, attachment is reflected in landing a sympathetic ear and providing help or advice. This act can be carried out as ends in themselves when it pleases us to help others for the sake of helping. But quite often, they are also means. Means for the individual who wants to get, in return, some marks of respect, affection, love, or friendly help. And in order to get these valuable services, the individual chooses to create and maintain relationships with other people through friendship, wedding, parenthood, and other kinds of associations. So attachment, as a means towards ends, clearly falls under a proxological analysis. The second element, commitment to conventional lines of action. This commitment explains why most of the people, most of the time, do not carry out any criminal act. And this is very simply because if they were caught, these conventional lines of action would be threatened by legal or informal sanctions. Their educational career would be at risk, or their job, or their family life, or their spare time activities, et cetera. And the proxological translation is here obvious. The values of the ends, sought through conventional lines of action, are higher than those of delinquent lines of action. In other words, carrying out a criminal act would, in this case, result in a psychic loss. It's also interesting to note that Hirshi uses a correct conception of subjective cost, the cost of a delinquent act is not the legal and informal sanctions that may ensue. It is the ends, and strictly the value of the ends, that could not be reached anymore if these sanctions were incurred. So this is a nice illustration of the Austrian concept of subjective cost. To sum up, the theory of social control explains that the weaker is the bond to society of an individual, the less he is attached and committed, the more he tends to carry out delinquent acts. And this theory can be considered in the interpretation I have given as a proxological theory. Most people follow the rules most of the time because there's a social control, inciting to conformity, and the avoidance of deviant acts, but this control is not an external force emanating from a holistic society. It can and should be analyzed in terms of ends, means and instrumental rationality and psychic profit. Now, if the theory of social control is right in that the bonds of delinquents to society are weak, then the question of group delinquency immediately arises. How is it that delinquency is quite often a group phenomenon, especially juvenile delinquency? Are not delinquents tightly bonded to the group of peers with which they carry out their delinquent activity? And this was the starting point of the culturalist theory, whose premise is that delinquency requires an interpersonal transmission of techniques and values that can only take place in a small and tightly-knit group. This is pure culturalist theory. Social control theory, on the other hand, claims that delinquents are weakly bonded even to their delinquent peers. A fact that has indeed been corroborated by empirical study. A simple and convincing praxeological explanation of group delinquency has been provided by Maurice Cusson, whom I have supported before. He shows that a delinquent act is easier and less risky to perform when in group. In a burglary, for instance, accomplices are quite helpful. They can monitor the area, help in picking up and carrying more spoils. The burglary can thus be quicker and safer for the offenders. In a holdup or a robbery, a group of criminals is more frightening than a single individual and reduces the risks that the victims will refuse to comply, flee or even attack the offenders. In the case of shoplifting, the accomplices can distract the seller while the stealing goes on smoothly. And furthermore, in the case of teenagers, the members of the group can turn delinquency in a sort of game in which each one challenges the others to perform delinquent acts. So with the group, delinquency is safer, quicker, more efficient and possibly also funnier. In other words, constituting a group is a means to reach the valuable ends looked for through delinquency. The culturalist theory explains the constitution of delinquent groups through a quite mysterious and largely ad hoc socialization process. But we see that the explanation provided by Cusson, on the other hand, is crystal clear and rests upon solid proxological ground. Let's now turn to another crucial feature of delinquent action, namely its impulsiveness. The concept of impulsiveness can be translated into the economic language as high time preference. And again here, as we shall see, the Misesien conception of action is highly relevant. The impulsiveness of teenage delinquents and of adult criminals has been noticed for a long time and by several authors. The most detailed analysis to date has been developed by Gottfriedson and Hirschi in the book which is my personal favorite on the whole subject of delinquency, A General Theory of Crime, 1990. That starting point is a description of typical delinquent acts such as burglary, robbery, homicide, auto theft, and so on. Here is, for instance, their description of the typical burglary. I quote, a young male or group of males knocks on a door not far from where he lives. Finding no one home, he tests the door to see if it's open. And if it's open, as it often is, he walks in and looks to see if the dwelling contains anything of interest that he can quickly consume or easily haul away. In most cases, the proceeds of the burglary are quickly consumed, used up, given away, or discarded. Unquote. Of course, not all burglars fit this pattern, but this is the typical burglary and the basic nature of this activity can only be deduced from a typical scenario, not from the very rare and unusual burglaries reported by the mass media or from those entirely fabricated for movie audience. Based on this understanding of what burglaries and other acts of violence or fraud typically look like, excuse me, Gottfriedson and Hirschi conclude that almost all delinquent acts share a series of essential features that go as follows. They provide a quick and easy gratification of desires. They are exciting and thrilling, but offer few, if any, long-term benefits. They require little skill or planning and they show insensitivity to others since they result in suffering of the victim. So in short, the typical delinquent act displays all the characteristics of an impulsive act and people who commit this kind of act on a regular basis can be labeled impulsive. They tend to grab very short-term gratifications while jeopardizing their long-term projects, assuming they have any. In the terminology of Gottfriedson and Hirschi, they are characterized by a low self-control. Maurice Cusson uses a suggestive expression. He calls this psychological feature, presentism. And in economics, of course, we would say that they have a very high time preference. Now, in the very first chapter of his treatise, von Mises devotes a section to the analysis of the relationship between impulses and action. He explains that, of course, people have impulses, impulses to grab things that are not theirs, to molest people that they dislike, and so on. But most of the time, they choose to resist these impulses because yielding to them would be much too costly. And this, what is it? It's the core of the theory of social control. And von Mises adds two very interesting considerations. First, when an individual yields to his impulses, it's still an action, not an automatic behavior. Emotions, impulses affect the terms of the choices faced by the actors, but they do not prevent nor replace action. Anger, for instance, may favor the use of physical violence as a means. But whether in anger, in fear, or in a quiet mood, the person acts nonetheless. She consciously uses means in order to reach a chosen end. And here is his second consideration. The reason for yielding to an impulse is to be found in high time preference. The benefits from an impulsive act are immediate, but the negative consequences are often suffered at a later date. So the higher the time preference, the more the future inconveniences are disregarded, and the more likely the person will yield to her impulses. And this, this is the core of the theory of low self-control by Gottfriedsen and Hirschi. So the analysis offered by von Mises on the subject of impulses, even though it's quite short, is brilliant. He anticipates some of the most important theoretical developments that have taken place in the following decades in the study of delinquency. A very important phenomenon can also be explained with the help of the concepts of impulsiveness and time preference. It's the relationship between age and delinquency, which is called the age curve. So let's take a look at the following figures that show the relation between the age of offenders and indicators of delinquency. The first one here, age curve, male criminal offenders, England and Wales, 1842, 1844. Second one, age curve of male criminals at first conviction, England, 1908. And the last one, age curve of arrest for property crimes in the United States, 1999. So all these curves are from very different years and very different countries, but they show exactly the same pattern. The tendency to commit delinquent acts peaks around age 18, then quickly diminishes. So a massive and natural phenomenon of rehabilitation occurs with age. How can this phenomenon be accounted for? Certainly not by the culture's theory, which is in fact contradicted by this pattern. Why would small primary groups of individuals socialized within delinquency, why would they tend to dissolve and disappear after age 18? Godfreytson and Hershey have provided an explanation that I find quite convincing for this phenomenon. They say that when people grow up, they tend to become more and more mature, which means that their time preference decreases. They become less and less impulsive with age. So when people age, they tend to commit less and less delinquent acts, hence the shape of the age curve. But it must be made clear that this process that occurs with age is not a praxeological phenomenon. It's a psychological phenomenon, of course, and ultimate data from a praxeological viewpoint. I would now like to take, as a last example, another major development in Sociology of Delinquency, the so-called routine activity theory. It was expounded at the end of the 1970s by Lawrence Cohen and Marcus Falson, to criminologists. And these authors start from a puzzling phenomenon. Between 1960 and 1975 in the United States, delinquency exploded. Robberies increased nearly fourfold in just 15 years. Aggravated assaults increased nearly threefold. Rape, homicides, burglaries, each also increased nearly threefold according to police data. There's, of course, much to be criticized in police data. But since they are collected roughly in the same way year after year, they offer a quite reliable image of the evolution, not of the level, but of the evolution of delinquency. This explosion of delinquency is all the more enigmatic that this very period was quite favorable from a social and economic point of view. Unemployment was low. Poverty in the official sense was diminishing and income inequalities were also decreasing. So it's impossible to explain this surge in delinquency from 1960 to 1975 by the usual scapegoats, such as unemployment, poverty, and inequality. The starting point of the explanation offered by Quen and Felsen for this puzzling phenomenon is a consideration of the minimal conditions for predatory criminal act to occur. They contend that three minimal conditions are required. First, a motivated offender. Second, a suitable target. And third, the lack of a capable guardian. But they immediately cast aside the first condition, a motivated offender. They take for granted that there are motivated offenders, always have been and always will be. They focus instead entirely on the two last conditions, which are both purely situational and from their own, their theory is extremely simple. If it so happens that suitable targets multiply and that capable guardians are more and more lacking, then we should expect an increase in the number of criminal acts. And they show that these are just the circumstances that occurred in the period of the 1960s and 70s. Let's just take one example, burglaries. Thanks to the increased quantity of consumers' goods produced, houses were more and more often filled with suitable targets such as electronic devices, vinyl records back then, bottles of alcohol, jewelry, fancy clothes, and so on. Furthermore, in the case of electronic devices, their weight and size significantly decreased during this period, so that they became easier to carry away. Now, as far as capable guardians are concerned, they were indeed more and more often lacking during this period. Houses were more often empty during the day simply because the proportion of women working was increasing. Also, families were leaving their houses empty to go on vacations, vacations that lasted for longer and longer periods. So, the routine activity of American households around their house was greatly altered during the 60s and 70s, and this is the explanation of the name of their theory, routine activity theory. This alteration in the routine activity explains for a big part, the upsurge in burglaries and in other aspects also. So, in a general way, these authors show that in the period considered, delinquent action has become more rewarding, less difficult, and less risky. So, the initial puzzle, an explosion of delinquency in a quite favorable economic situation, has been solved by adopting a strictly praxeological approach. The authors did not care at all about the motivational or cultural aspects of delinquency. Instead, they analyzed delinquent acts or means toward ends and discovered that these acts could henceforth reach more valuable ends at lower costs. In the Mesesian language, we can say that the psychic profit of delinquent acts tended to rise relative to other kinds of acts and that therefore, delinquent acts were more often carried out. Culturalism, however, has not said its last word. Let's take a look at the following figure. Trends in murder and robbery United States 1972-2006. A surprising phenomenon occurs in the 1990s. During this decade, the delinquency rate in the United States has been divided by two. This is a very substantial drop. Now, this evolution is quite difficult to explain. The most obvious cause would be the huge increase in the number of people behind bars. According to the statistical calculations of some authors, this policy has had a quite strong negative effect on criminality, but other authors find weak correlations. So, there's no consensus between the statisticians on this topic. And furthermore, in Canada, a similar strong decline in delinquency has occurred, which cannot be explained by an increase in the incarceration rate since no such increase has taken place there. And among the other explanations, no one is really convincing. For instance, the strong economy of the 90s, the changing demographics with a lower proportion of teenagers and young adults, the increase in the number of the police, the improvements in police organization and practice, etc. Even when all the aforementioned causes are taken together, they do not seem to deliver a satisfactory explanation of such a significant and unexpected phenomenon. So, some criminologists fall back on a culturalist explanation. Mark Wimet, for instance, Canadian criminologist, thinks that the decrease in criminality in the 1990s could be an effect of, I quote, the new ethos of moderation, unquote, that characterizes the US and Canada since the 1980s, the new ethos of moderation that's observable in the reduction of overall drinking and smoking. The drop in delinquency could thus be explained by an important change in collective values. And the famous American criminologist, James Q. Wilson, also considers that the usual factors are not sufficient to explain the phenomenon. And he concludes a recent paper in the Wall Street Journal by saying that, I quote, crime in the United States is falling because of a big improvement in the culture, unquote. Well, it's true. It's true that major surveys in moral values conducted worldwide tend to show that culture is slowly but surely improving. But this culturalist explanation is hardly satisfactory. The connection between the two phenomena, criminal behavior on the one hand, and moral surrounding on the other is never clear in the culturalist approach. And this is the main reason why this approach is unsatisfactory and inferior to the praxeological approach. Let's now turn more briefly to the second main element in the Mises Yen conception of social science, namely the a prioristic character of praxeology. This issue is controversial, not here, but outside. It's not an exaggeration to say that almost all social scientists today reject a priorism, almost all of them. They are positivists in the sense that they believe that in social science, a theory can be corroborated or falsified by empirical data. And they think quite simply that social science is an empirical science in the exact same way the natural sciences such as physics, chemistry, and so on. This positivistic viewpoint is, of course, totally rejected by von Mises. According to him, the theories of human action are logically deduced from the postulate of action combined with specific initial conditions. And the postulate of action states that human action consciously uses means in order to reach chosen ends. This postulate is a priori true. It would make no sense to test it against experience in order to check its validity. So the whole edifice of theoretical social science has an a prioristic character, too, since it's logically deduced from this postulate of action. And I will now show that the development of the sociology of delinquency, properly understood, exemplifies the Mises Yen a priorism. One of the main episodes in the sociology of delinquency in the 20th century was the critique and demise of the culturalist theory, as I have explained above. As we have seen, this theory has been convincingly criticized by showing with the help of empirical investigations that criminals do not have a system of values opposed to that of conventional surrounding society. So it seems that we have here an example of an empirical refutation of a theory of social science, namely the culturalist theory of criminality is empirically refuted by the data, by the empirical data. But according to von Mises in social science, theories can be neither confirmed nor refuted by empirical investigation. So does this episode, very important episode in the history of sociology, contradict the Mises Yen a prioristic conception and the answer is a resounding no. In this case study, the empirical investigation shows that criminals do not have a system of values that extols criminality as such. But the question, do they have an antisocial value system, or do they not? This question is purely empirical. It's devoid of any theoretical content whatsoever. It is a historical question whose answer is to be found in an examination of historical evidence. And this is just what sociologists such as Matzah and Hirshi have done. They have analyzed some relevant historical material collected with the methods of observation, interview, surveys, et cetera. And they have concluded from these historical sources that so far they could tell criminals do not have a value system opposed to the conventional one. Their statement is an empirical generalization from the little number of cases that they have studied to criminals in general. They resort to an inductive inference in order to reach an empirical generalization, an empirical generalization. But this kind of generalization is not, not at all a universal low. It clearly belongs to the branch of history, not of praxeology. In our society, we have good reasons to think that most delinquents, if not all of them, share the common system of moral values. They are not deeply committed to it, obviously, but they share it nonetheless. And this is a historical statement that could be proved wrong in another society or at another period. So the refutation of the culturalist theory is not at all the refutation of a praxeological law. It is the rejection of a historical premise of the culturalist approach. And Misesien's apriorism is in no way contradicted. In fact, it's not even challenged by this example. The routine activity theory offers another example that shows the relevance of epistemological apriorism in the social sciences. This theory, as we have seen, explains the great surge in delinquency in the 1960s and 70s by a deep change in the routine activities of American households, and especially the dispersion of these activities away from home. Stated in a positivist vocabulary, this theory is a hypothesis according to which delinquency, first variable, is positively related to the dispersion of activities outside of home, second variable. In order to test this hypothesis, the authors calculate an empirical indicator of dispersion and they find that there is indeed a positive and statistically significant correlation between the level of delinquency and the intensity of dispersion outside of home, even when economic and demographic changes are controlled. So the scientific enterprise of these criminologists can quite easily be expressed in a positivist framework. They formulate a hypothesis and then test it against empirical evidence. But this interpretation, strictly speaking, is incorrect. In fact, the authors expound a praxeological theory and their empirical study neither corroborates nor refutes this theory. Here is, I think, the praxeological core of the explanation provided by Cohen and Felsen. When an action, for instance, a delinquent action, becomes more rewarding, less risky, and less difficult, then it will tend to be more widespread, everything else equal. Can this statement be empirically tested? No, it's a pure logic of action related to psychic profit and it should be noticed that the authors never even attempt to test this core statement. But then what's the meaning of their empirical study because in their paper there is a very large empirical part? Is this empirical investigation useless and irrelevant? No, it's in fact very useful but must be correctly interpreted. It's not an empirical test of the theory. Rather, the empirical study is intended to check the conditions necessary for the application of the theory. Are these conditions indeed present in the historical reality of a given period? Delinquent acts will be more numerous if they become more rewarding, less risky, and less difficult, everything else equal. This is the praxeological reasoning with true, true with a prioristic certainty. Now in the period under study, do these acts indeed become more rewarding, less risky, and less difficult? This is the question that the empirical or historical investigation has to answer. At first sight, it may seem as if the authors are testing their theory against the fact, thus demonstrating that Misesian a priorism is erroneous but they are not. Their core theory is a priori true and they test its applicability to a specific historical period. Misesian a priorism is not contradicted, it's in fact exemplified by this very important case study in society. This example of the routine activity theory and the previous one of the cultural approach, both show that if words are not used carefully, they can mislead us into adopting the positivist viewpoint. When we say the cultural theory has been refuted by an empirical investigation, we use the word theory in a questionable sense. We should say more rigorously that an empirical premise of the culturalist paradigm has been invalidated. When we say that the routine activity has been tested, routine activity theory has been tested against the empirical evidence, we should say that the conditions of applicability of the routine activity theory have been checked for a specific historical period. The scientific vocabulary is full of positivist traps that can only be avoided if we stick to the very strict demarcation specified by von Mises between history on the one hand and praxeology on the other. Let me now conclude. In order to pay tribute to Ludwig von Mises, I have tried to show in this lecture that his thinking on the foundation of social science is fruitful and relevant well beyond the realm of economics. I have taken the example of the sociology of delinquency, but there's no doubt that all the branches of sociology could be considered as well. His conception of action and his a prioristic epistemology are both essential in order to understand the development of the sociology of delinquency. And his praxeological framework in turn is nicely exemplified by some of the most important theoretical developments in this field since the 1950s, such as social control theory, low self-control theory and routine activity theory. It's now time for me to thank you very much for your attention, thank you.