 Hello everybody, I should say this lecture is usually given at Mises Yu by Hans Hoppe, who couldn't come this year. I should mention to anyone who might be confused that I'm not Hans Hoppe. I don't think it would be a performative contradiction for me to say that I am Hans Hoppe, but the statement would nevertheless be false. Okay, so one claim Mises makes in human action is a quite surprising one. He says that economics is the newest of the sciences. This seems like an odd thing to say. Now of course, Murray Rothbard in his great history of economic thought suggests that economics really began in the Middle Ages, if not earlier. But even if you take the view, say that economics began in the 18th century, it still seems unusual to say that economics is the newest science. You could say, haven't there been sciences that have developed since the 18th century, such as astrophysics or neurobiology or all sorts of other sciences, so cognitive science. How can Mises say that economics is the newest science? In saying this, he has a very definite point that he says that he's aware of these extensions of existing sciences, but he says disciplines like astrophysics or neurobiology are just extensions of already existing sciences, but he claims that economics is a new science because it's developed a completely different method of studying the world from that used in the natural sciences, so economics is in that way new. You see, for Mises, issues of method of how we engage in inquiry are extremely important. Some people don't want to talk about this, they'll say, well, let's get to the real economics. Fortunately, that isn't the prevailing view here. There wouldn't be a place for me in giving these lectures, so I'm glad that isn't the prevailing view, but if anyone held that that said, well, this isn't really economics, this is a concerned method, the person wouldn't be true to the spirit of human action because issues of method are very central for Mises. Now, to understand what this new method is, I think we need to understand what Mises thought the situation confronting economics is, that according to Mises, economics, in this respect, it's like the physical sciences, is a discipline that discovers definite laws of how the economy works. This fact that the economics has definite laws is one that is distasteful to many people. They don't like this, they don't like the fact that they're economic laws. Why is that? Why would they not like economic laws? Well, if they're economic laws, they limit what policy makers can do. For example, it's a consequence of one economic law that minimum wage legislation is unlikely to achieve the goals that the policy makers want for minimum wages. Minimum wage legislation won't help workers without hurting other workers. So suppose you're a policy maker and you're confronted with that conclusion, you're not going to like it. We can imagine, there was actually one case, there was an American politician, Huey Long, who was the governor of Louisiana in the 1930s, and he had a program which had the title Every Man a Millionaire, and his proposal was simply to print up enough money so everyone would be a millionaire. Now, if you hold that as your view, you're obviously not going to like a discipline that tells you that program won't achieve what you want. So there's opposition to the notion of economic law, which you don't find in the physical signs you don't find, at least not very many people at any rate, saying, well, there's a law of gravity, but I don't like this. I think people should be able to move in any way they want. So let's forget about the law of gravity, that people don't treat law of gravity with levity of that, sorry. Now one source of opposition to economic law that Mises was especially concerned with was the German historical school, sometimes he calls this the Prussian historical school. This was a group that was prominent in the late 19th century, mainly in Prussia, consistent of economists such as Gustav Schmoller, Adolf Wagner, Werner Zombart, who Zombart continued into the 20th century. Mises at one time was a friend of Zombart, but their friendship ended when Zombart supported the Nazis after Hitler took over in January 1933. So what the members of the German historical school said was that there really aren't economic laws, that an economist should just collect data on prices of various kinds or discuss the origins of economic institutions, such as banks, and in fact Schmoller was done pioneering research on the history of the Prussian economy, but the German historical school said, well, there aren't really economic laws that apply universally. There are just all the economists can do is study the economies of particular countries or particular historical periods. And one reason or motive I should say that the German historical school economists thought that was that they were strong supporters of certain policies by the Prussian government which called for intervention in the free market. They favored very much a state-managed economy, so they didn't like the conclusions of economics which tended to suggest that the free market would work better. So this is one source of opposition to economics that Mises was especially on Mises' mind. There's one funny story I remember that Murray Rothbard used to tell. Rothbard went to Mises' seminar, once gave a paper where he gave his criticism of the notion that there can be a monopoly price on the free market. I'm sure some of the other lectures will be getting into Rothbard's argument at this point, but Mises' response was, oh, I see you're a Schmoller-ite. But Rothbard was, I guess, too intimidated to ask Mises what he meant by that. But that was his comment. Now there's a more extreme version of opposition to economic law which Mises calls polylogism. And this is the view that, remember the German historical school said that all knowledge, economic, there aren't any economic laws or just separate economies. We can study particular historical periods, but we can't study, there aren't any universal laws. Now polylogism is more extreme view. It says that there aren't really universally valid laws of thought at all, that they're just different groups, say different economic classes or different races that have totally different ways of thinking. For example, the Marxists, or at least some Marxists, said there's a proletarian logic and a bourgeois logic, and the Nazis thought that different races had different logics. For example, some of the Nazi physicists rejected Einstein. They said this is Jewish physics. Well, as I say, this is a more extreme view of the historicist position, but Mises suggests that here again, the motive for this view is opposition to economics. And he thinks that usually, although this example of the Nazis is perhaps an exception to that, people who say that they're polylogists don't really reject the physical sciences. They just reject economics. So what Mises thinks is there's opposition to economic law because people don't like the policy conclusions that they think come from accepting economic law. Now we'll see very shortly what all this has to do with the proper method. And the way we can see this is by considering a less radical position, the one where the radical position would be there's no such thing as economic law, but there is a more moderate position, which is some people don't reject economics altogether. They say, well, economics applies only to the money making aspects of life. Some people say business people in particular are trying to maximize profit. So on the assumption that people are trying to maximize profit, then we can come up with economic laws, but trying to get as much money as possible is just one part of life. People have all sorts of other motives besides trying to get as much money as possible. So the people who hold this view, they say, well, economics is just dependent on certain special assumptions. I said it's just dealing with Homo economicus, which means economic man. It isn't dealing with human beings in their entirety. So again, this is a way people who hold this view can question the implications, the possible implications of supporting the free market of economics, because they can say, well, okay, maybe if we were going strictly on economic theory, we should reject intervention into the free market. But there are all these other considerations that have to be taken into account of, so then we can still have room for interventionist measures that say, well, okay, they don't conform to economic theory, but after all, economics is just part of life. Now, Mises holds that 19th century economics didn't have the resources to counter this view. They couldn't reply to it. That's to say the view is that economics is just dealing with one aspect of life, namely the aspect where people are trying to maximize their money income. And the reason 19th century economics couldn't address this point is that the 19th century economists, that's to say the ones before the development of the subjective theory of value, had a cost of production theory, mainly based on labor costs, but other costs as well in some extent. So if they were confined to the cost of production, they really couldn't, they didn't have a general theory that analyzed all the choices that people make. They could just deal with certain choices, namely those that involve trying to maximize your money income. So they don't have a general science of all choice. And it's trying to come up with such a general science is where this distinctive method comes in that Mises says makes economics a new science. In order to counter this claim that economics just covers part of life, namely the part of dealing with Homo economicus, we need to reject a cost of production theory and come up with a subjective theory. It says we can explain whatever choices people make, whatever values they have. We can have a science that explains, gives us laws of human action, dealing with whatever these choices are, not just choices that are trying to maximize money income. And so we need, Mises thinks, a new method than the one used in the physical sciences to answer this question. Mises also thinks that if we, this new method will help us in understanding economic calculation. So Mises says that he's dealing with a general science of human action. He calls this praxeology. Now one point here that sometimes people miss, that as you'll see, there is a particular method, deductive method that Mises uses in this general science of human action. And sometimes people think praxeology refers to this deductive method or this special way of proceeding. But praxeology is the science of human action itself, not the method that you're using in carrying out praxeology. If you're doing praxeology in the correct way, then you'll be using this deductive method. But the deductive method itself isn't praxeology. And then within praxeology, Mises says there's a discipline that he spends most of the time of human action, talked about that he calls catalactics, which is the study of exchange. So this is part of praxeology. Now there are suggestions that besides economics would be broader science, where you consider not just exchange, but individual actions, such as Robinson Crusoe economics. But there are suggestions that there are other branches of praxeology as well, but Mises doesn't spend a great deal of time saying what those are. Now as you would suspect from the title human action, action is the most basic category in praxeology. By action we just mean purposeful behavior. Now one point to bear in mind here, I think is a very important one, if people sometimes get a bit confused on this, they'll think of something like they'll say well, in praxeology it's supposed to be this deductive science about human action, but how do I know, say it works by thinking about the concept of action, but how do I know if I'm thinking about action that I'm coming up with anything other than my own thoughts and actions? How do I know that this applies to other people? Maybe I'm just coming up with some kind of deductive science that's just about myself. How do I know it applies to other people? But this, to ask that sort of question, is I think a fundamental misunderstanding of what Mises had in mind. Mises is talking about action in the world. There's such as my giving a lecture, you staying in your seat, not running out of the lecture. Of course, if I were in your position, that would be exactly what I would be doing, but never mind that. Okay, so again, we're talking about actions in the world. Mises is not trying to solve the philosophical problems of skepticism. Say we have, in philosophy, we'll sometimes have questions like this to say, imagine that I think I'm now experiencing various things. I think I'm giving a lecture at Mises, you, but suppose, in fact, I was just a brain in a vat and there were scientists who were just had electrodes attached to my brain and they were just giving me, bringing about that I had the experience that I was lecturing to the Mises Institute. How do I know that that is, that that's false? How do I know I'm actually lecturing to the Mises Institute? Given that on this hypothesis, I'm having exactly the same experiences in either case. Now, Mises is not trying to answer that question or that sort of question. He's assuming, he's taken for granted that we're actors in the world and he's talking about actions, that real life actions. He's not trying to solve any kind of a problem of philosophical skepticism. Now, just one other point about actions, normally, when we talk about actions, it'll involve some kind of physical movement of the body. Say, you're doing something, you're making some sort of change in your body, but it doesn't have to. There are exceptions that, for example, suppose I say, everyone who agrees with me signify this by remaining seated and you all remain seated, so you've all agreed with me. So you've acted, you haven't moved, but you've acted, you've agreed with me. That would be under that convention you, by remaining seated, you're acting. So not all actions involve physical movement, although that's the general case. Now, we can now, we're last in a position to answer this question that I raised before. How can Mises reply to this modified rejection of economic law? Remember, there's a first, there's the German Historical School and some of the people say, there aren't any economic laws at all. Then there's this other less extreme group that says, well, maybe there are economic laws, but they apply only to a limited sphere of action, namely action that has the motive of maximizing money income. So, but economics has to be then considered in connection with other disciplines that might tell us about other motives. So to answer that, Mises needs to have a general science of action that holds regardless of what the motives people have are. And this is praxeology. In praxeology, it doesn't say anything about what goals people have or what the particular means they pick to achieve these goals. It's concerned rather with the structure of any action. So no matter what the action is, praxeological laws apply to it. Well, that's a very striking claim that we have laws that apply to any action, regardless of the motive or regardless of the means in the action. How do we get such laws? The way we do that, according to Mises, we just consider, we take any action we want, say, my giving a lecture, any action we want. And then we say, we try to abstract away all the particular features of the action. So what's left is just the general structure of any action. We just want to come up with the general structure that would apply to any possible action. So we're abstracting away the feature. We just start with any particular action we want, and then just abstract away the features that say it's this action rather than that action. We just want to get what are the general features of any action. And Mises calls this principle methodological singularism. He has sometimes a tendency to come up with these unusual terms, polylogism, methodological singularism. He had a very wide vocabulary, sometimes likes coining all sorts of new terms. It's probably to confuse students, I suppose, is one reason he did that. Now there is another principle of basic to praxeology that's different from methodological singularism. Remember, methodological singularism is the view that you consider any action you want. You abstract away all the individualizing features of the action. So you're left with just the general structure of an action. Now methodological individualism is the principle that only individuals act. So suppose we say that we can talk about nations and classes, but a nation and class can act only by individuals who compose it, acting in a certain way. There is a view that some people are what we could call eliminativists about nations or classes. They say, well, all that really exist are individuals. Nations and classes are just abstractions or collections of individuality. Mises isn't committed to that view. All that he says is that methodological individualism is only individuals act. For example, when the U.S. Congress, when we say America declared war on Japan, December 8, 1941, how is that to be analyzed? Well, it's in response to President Roosevelt's speech on that day. The members of Congress voted for a declaration of war. And then because of the institutional structure of the U.S. government, various things happened and at some point American troops started attacking Japanese troops. So it would be analyzed just in terms of individuals. It wouldn't be that the nation is acting in some other way. I sometimes like to tell a story. I at any rate thought it was funny. Sometimes audiences don't. There was a very good songwriter and comedian named Oscar Levant. He's probably long before the time of most of you who once said, why is it that we can say Germany invaded Russia in 1941 or Hitler invaded Russia? But we don't say Germany invaded Stalin or Hitler invaded Stalin. Now, I don't think that that's too relevant to the point about methodological individualism, but I just thought it would be a good opportunity to give you that story. Why not? I say so now you might think this principle of methodological individualism, let's say that only individuals act seems obvious. Who would deny that? Who would say, for example, suppose we're trying to figure out responsibilities for the Iraq war? So suppose somebody said, well, it wasn't it wasn't President Bush or President Obama or Congress. It was just America declared war. And this isn't to be analyzed in terms of action by particular people. That would seem a very silly view. So you might think about why does Mises have to say that? Nobody would deny that. But in fact, there are people who did deny they were much more influential when Mises was right. There are people there were people who thought say that there's kind of a racial spirit in that acts directly. Individuals are simply mechanically carrying out the policies of this spirit. Some people take Hegel to be a proponent of that view. I think Mises takes Hegel to favor that that's somewhat controversial. But in any bet, we have to remember both methodological singularism and methodological individualism are key principles of praxeology. Now, I want to get into a little bit more detail about ends and means because remember, action is purposeful behavior. Every action involves an end or a goal and means that the actor has chosen to achieve the goal. So one very interesting point I think that Mises makes is that when he's talking about means, there are human category that they don't exist in the world apart from the way people consider them. Say if we imagine we have, say, a combination of wood and metal that people have made into a hammer. So we say, well, this is a means just because people take it to be a means. It isn't that this combination is just in nature would be a means. It just is a means because people have intended that way, people have devised it. So Mises says here, I give a quotation from the pages according to the scholars edition of Human Action published by the Mises Institute. External objects are such only phenomena of the physical universe. It is human meaning and action that transforms them into means. So when you're talking about a means, it's something that human beings have taken to be a means. It isn't an absolute that exists apart from human thought. So Mises generalizes this point where he says that the means is something that's taken to be such by human being. He says, praxeology isn't about the external world apart from human being in the physical sense, at least in some of the physical sciences. We don't consider human beings, say, in physics, you're concerned with motions of particles of various kinds. You're not concerned with how human beings view those particles. So if you say they're various subatomic particles, those particles, if the physics are correct, are there regardless of what human beings think about them. They're just there. But in praxeology is not like that. We're concerned with the meaning human beings give to the world. Now note, to refer to a point I made before, it doesn't follow from this that praxeology is all in the mind. So what we're talking about is really just thoughts. It's about the external world, but it's the external world as human beings take it. And I give another quotation here from me. Praxeology does not deal with the external world, but with man's conduct with regard to it. So when he's saying not with the external world, he's meaning not with the external world apart from human beings. But it is the external world in regards to human conduct toward it. So again, it's not purely mental, but it's how human beings take the external world to be. Now, carrying on a bit further with this subjective point, means are what's taken to be means by human being. A means is whatever someone thinks will enable him to reach his goal. So it doesn't have to be the case that the means really will enable the person to achieve his goal. It's just as long as the person, we're trying to explain particular people's actions, so what counts is what they think will work. Suppose, say, someone wants to go to, has a very important business decision, and he wants to find out what's a lucky day by consulting his horoscope. So that's the means he uses, consulting his horoscope, is the means he uses to decide when to hold his meeting. So it doesn't matter if astrology is false, as long as the person thinks that that's the way to proceed, that's the way he's going to proceed. We're not concerned to try to evaluate from some external point of view whether the person is right. I should say, I don't believe in astrology myself because I'm an Aries and people with that sign tend not to believe in astrology. So again, I have another quotation where Mises gives this point, he says, in dealing with prices, economics does not ask what things are in the eyes of other people, but only what they are in the meaning of those intent on getting them. So if we're trying to explain why people want certain goods, then we're going to be concerned with the preferences of those people, not other views on what those goods are or say on whether people have chosen appropriate means to achieve their goals. We're concerned with the subjective views of people both in their goals and what they think are the means to get them. So when I say why are we doing this, well, we're trying to explain actions. So if you're trying to explain actions, you're going to be concerned with the goals or the preferences that individuals have. We're not trying to evaluate this from some external point of view. So praxeology is not a normative discipline. It doesn't tell you what you should choose. It's just saying what are the goals people do choose. Now, there's a possible exception to this. In some cases, we can say that if someone picks a certain means to achieve a goal, we could say that that means is unsuitable. For example, suppose we say we want to help workers get more money and not hurt any workers in doing that, then minimum wage laws won't be a suitable means to achieve that. We could make statements of that kind. But means hold, if we just talked about an end goal that wasn't a means to some other goals, just an ultimate end, then we can't say it's good or bad. It's just there. It's not part of praxeology to evaluate people's ultimate ends. So again, the principle is we can't evaluate ultimate ends. We can say, in some cases, a certain means is suitable or not to achieve an end. But what a means is will be subjective in the sense that the individual, it means it's something that an individual takes to be a means, whether rightly or wrongly. Now, as you might expect, means is rejects the categories normality and perversity in praxeology. Perversity is a word I guess you don't see too much anymore. But in time, means was writing, it was in more general use. So again, what we're concerned with in praxeology is that we're concerned with what individuals choose and how they act, not whether they conform to people's standards of what's normal. And I should say, means is one a bit further than that. And this is not part of praxeology. It means himself thought there weren't objective standards of what were good and bad. This is a kind of ethical, evaluational subjectivism where that's a position in moral philosophy not in praxeology. That's not part of praxeology. You don't have to agree with means is that there aren't any objective standards. But all that's important is that those views are not part of praxeology. So if you're trying to explain an individual's values, what's relevant are the values that individual holds. If you think, say, the individual is acting in an immoral way, that isn't going to help you explain the person's choice. What you're concerned with is that person's preferences. Now we now can get into, in the time remaining, say a bit about what is this method. We know now we want to have a subjective, we want to have a science that explains subjective choice. The person chooses, we want to have some laws dealing with action. So how do we do that? Now here we get into the part in human action that most people find very difficult. It's part one of human action, say the first 141 or so pages of human action. Most people find this very difficult, but in fact it's not, I think it's fairly simple, at least not as difficult as you might think. Now Mises says that the laws of praxeology are a priori truth. What do we mean by a priori truth? It's one that doesn't need to be justified by experience. It's one that you can realize is true just by thinking about it. For example suppose you say 2 plus 2 equals 4. So you don't have to keep counting out two objects, another two objects say, okay this one added up to 4, so I confirm the conjecture that 2 plus 2 equals 4 and then keep doing that. Once you think about 2 plus 2 equals 4, you realize it's true, so you don't require any testing of the statement to be justified in claiming it to be true. So Mises says the laws of economics are a priori in that way. Now why does Mises think that the laws of economics don't resemble 2 plus 2 equals 4? So why does he say that they're a priori true? Well he says that the propositions of economics just draw out the implications of the concept of action. He calls tautologies that to say they're true just because of the meanings of the terms in them. Suppose you say every action involves the use of means to attain an end. Well that's just the definition of action so you don't need to examine actions say does this one have an end or does this one have a mean? It's part of the concept of action that an action, it is the definition of action, action is the use of means to achieve end. So Mises claims that the laws of human action or tautologies they're just drawing out the implications of the concept. Because we'll see this is a move could land him into difficulties but he has ways of getting out of them. Now the obvious objection I'm sure would have occurred to you already is if we just say economics consists of tautologies then it isn't really teaching us anything new about the world all we have is a list of definitions or parts of definitions tautology can also be a logical law. So the objection would be well okay you can make say economics is consists of a priori true propositions but what is this what is this going to do for you're not going to learn anything just from all these definitions you're just going to be elaborating a system of definitions. So Mises has replied as well look you could say that in mathematics this is giving the consequences of definitions of an axioms but people wouldn't say mathematics isn't teaching us anything new just in the read it just because you're starting with definitions the implications of those definitions aren't always obvious sometimes you start with tautologies but what you get from them can be very surprising propositions they may be tautologies if you take logical implications of tautologies but at least not all tautologies are obvious some are very surprising. Now one point here and this is a point I must confess I made a mistake many years ago when I wrote that philosophical origins of Austrian economics book that was actually a talk I gave at one of these conferences years ago but I made the mistake I thought Mises says the truth of economics are synthetic a priori truth now what do we mean by synthetic well synthetic a priori truth would be one it's a priori we know it's true just by thinking about it we can know it's true just by thinking about it but it would not be one we could just discover to be true just by looking at the implications of the concept it would be one that's true we could be true about the world but not one that's just true from the nature of the concept so at one time I thought oh well Mises says thinks the truth of economics are synthetic a priori but in fact he doesn't say that in human action he says there he says there are tautologies which would be that they're not synthetic a priori truth whether he's right to hold that view is another question but that was his view so again the objection is well if you say truth of economics or tautologies they're just statements that are true just because of the meaning of the terms whether you're not telling you anything new but in his answer that is look at math in math you do get truths that are new in the sense of surprising so even if there are tautologies they're still telling you something new about the world now what I think is one of Mises most interesting contributions is his answer to another objection remember the objection we gave so far is well if the truths of economics of praxeology are a priori because they're tautologies then they're not telling you anything new and Mises answer is some tautologies can be very surprising to people now the new objection is different is even if praxeology in the way Mises explains it is gives us knowledge in the sense it's telling us things we didn't realize before it's some of these implications of concept of action aren't obvious or at least not obvious to most people when it we still have a problem if we've started with definitions and concepts how do we know those concepts apply to the actual world so we could say well okay we can get this very elaborate scheme of concepts but how do we know this is actually giving us knowledge about the world after all their mathematical systems that people can elaborate in detail but we have to be able to check that just by observation that that those postulates or action really do apply to the world so wouldn't we have to put in some kind of empirical testing so we know that we're really talking about the world we're not just constructing some system that may or may not apply to the world and I say I think Mises has a very interesting answer and his answer involves what he calls a priori concepts which are different from a priori propositions what I mean by concept is an idea where a proposition is a statement with it has a truth value suppose I say Socrates is a man so that's a proposition I'm making some claim about Socrates but the concept of Socrates isn't making any kind of assertion it's just an idea I have an idea who Socrates was or I have an idea of what the concept man is so I can say Socrates is a man I proposition consists of concept but it's not a concept itself so what Mises says is there are some ideas we need in order to make sense of experience in order certain aspects of experience and he holds and this would be the view that would get him into trouble with Ayn Rand I think it not only would get him into trouble but did get him into trouble with her he holds that some concepts aren't derived from experience because we need this these concepts in order to make sense of experience or in order to make sense of particular aspects of experience so he says well we can't derive these concepts from experience because having the experience presupposes that we have the concept for example suppose we didn't have a concept of money or medium of exchange then we wouldn't be able to understand what was happening when people were buying and selling say we would see people exchange giving pieces of paper to other people or giving people metal discs or of course you have to be careful in when you're giving paper money you have to always avoid counterfeit money I remember there was a story there was a man who was saying his friend got into trouble counterfeiting money said I tried to warn him I told him George Washington didn't wear a turtleneck sweater oh good there people were still laughing I'm glad of that okay so again if you didn't have the concept of money me's his things then you wouldn't be able to understand what people were doing when they were buying and selling we couldn't in his view get the concept of money just by watching people we have to have the concept in order to make sense of the experience so this is really me's his answer then to how do we know that the praxeology if it consists of these tautologies how do we know it applies to the real world he said well we know it applies to the world because we need these concepts in order to make sense of experience we wouldn't have the experience that we're having unless we were using these concepts so taking really the experience exists only because we're using these concepts so it's not an empirical matter whether these concepts really apply the experience doesn't exist in that in that in that form without the concept now he's gotten himself into this rather difficult position because he's accepted a particular view that I think one that Rothbard question I think is one that Rothbard had in my view good grounds for questioning me's is held the view that if we're talking about the truth a priori truth that's to say truths that we know to be true just by thinking of them or that we can know to be just by thinking about them then what we're doing is really just talking about concepts we're not talking about the world directly but we're just talking about concepts but we could ask the question why can't we know truths about the world just by thinking about them why would our a priori knowledge have to be confined just the concepts apart from the world I'm not suggesting that when we're talking about knowledge of the actual world we're talking about non-conceptual knowledge I'm just asking question why should we confine our priori knowledge just to concepts apart from the world out there apart from the physical world maybe they're parts of the actual world we can know just by thinking about it would seem if we rejected that that's rather one no that's rather an a priori judgment itself that we can't have knowledge of the actual world so Rothbard didn't accept this view that Mises had Rothbard thought that all concepts are derived from experience but we thought we could grasp necessary relationships in the world for example we could see that any exchange not only does involve a double inequality say I'm exchanging something with you say I get I have an apple and you have an orange and then we exchange them so I want if we exchange them and I want the orange more than the apple and you want the apple more than the orange so Rothbard thought well we could just grasp right away just by thinking about it we're talking about something that's there in the world we're talking about exchanges we could see that the exchange has to involve this double inequality we're not just talking about concepts in people's minds we're talking about exchanges but nevertheless we could know that these are true we could know certain truths about them just by thinking about it so Rothbard is so Mises answer again the difference is Mises is saying well we have these system of a priori we have a priori truths that are tautologies and we know that these apply to the real world because we couldn't experience the world unless we had the concepts in these a priori truth and Rothbard's view is more we can think about the world directly just no truth about the world directly just by thinking about them I'll leave it to you which if either these views you think is the better one or the one to be adopted I just a one point I should just mention before we leave the rather tangled topic of the a priori maybe it wasn't as easy as I falsely said it was but you know I do lie from time to time now one statement one claim some people make you remember I made I start off my lecture with a feeble attempted humor I said it wasn't a performative contradiction if I said I'm if I said I'm Hans Hopper that wouldn't be a performant contradiction now some people say well though what the test for an a priori proposition is that if you deny it then you'll be in a performative contradiction what do we mean by that well a performer there are some statements that you're if you make the statement that shows the statement is false for example suppose I say I'm now dead I probably a lot of you wish that were true but if if I say that my saying that shows that it's false because I couldn't say I'm now dead unless I was alive some people think well that's the test for an a priori proposition but it isn't because suppose suppose I did not I say 2 plus 2 does does not equal 4 well it isn't the case that I could say 2 plus 2 does not equal for only if 2 plus 2 did equal 4 and then also we could have statements that are performative contradiction but not a priori for example suppose I say I've never spoken an English sentence in my life that's a performant contradiction but it's not a priori truth that I've spoken an English sentence in my life okay so I and the last point I'll make is as I say it to carrying out this point remembering studying human action we're interested in the real world so sometimes certain postulates that aren't necessary or introduced for example that labor has disutility meaning by that that other things being equal we prefer leisure to labor that doesn't have to be true but the fact that we're introducing this empirical assumption doesn't make praxeology empirical because once we introduce it then we can reason deductively so I think I'll stop here so I hope we covered some of the basics of praxeology thank you