In Our Time - Logical Positivism

Episode Date: July 2, 2009

Melvyn Bragg discusses Logical Positivism, the eye-wateringly radical early 20th century philosophical movement. The Logical Positivists argued that much previous philosophy was built on very shaky foundations, and they wanted to go right back to the drawing board. They insisted that philosophy - and science - had to be much more rigorous before it started making grand claims about the world. The movement began with the Vienna Circle, a group of philosophically-trained scientists and scientifically-trained philosophers, who met on Thursdays, in 'Red Vienna', in the years after the First World War. They were trying to remould philosophy in a world turned upside down not just by war, but by major advances in science. Their hero was not Descartes or Hegel but Albert Einstein. The group's new doctrine rejected great swathes of earlier philosophy, from meditations on the existence of God to declarations on the nature of History, as utterly meaningless. When the Nazis took power, they fled to England and America, where their ideas put down new roots, and went on to have a profound impact.Melvyn is joined by Barry Smith, Professor of Philosophy at the University of London; Nancy Cartwright, Professor of Philosophy at the London School of Economics; and Thomas Uebel, Professor of Philosophy at Manchester University.

This BBC podcast is supported by ads outside the UK. Thanks for downloading the In Our Time podcast. For more details about In Our Time and for our terms of use, please go to BBC.co.com.uk forward slash radio four. I hope you enjoy the program. Hello, the Vienna Circle was a group of philosophically trained scientists and scientifically trained philosophers who met on Thursdays in term time in Vienna in the years after the First World War.

Out of their meetings, there emerged what's been called a revolutionary new doctrine, logical positivism. It rejected great swathes of early philosophy from meditations on the existence of God to declarations on the nature of history as utterly meaningless. The logical positivists were trying to remold philosophy in a world turned upside down,

not just by war but by major advances in science. Their hero was Albert Einstein. When the Nazis took power, they fled to England and America where their ideas put down new roots and went on to have a profound impact. With me to discuss logical positivism Barry Smith, Professor of Philosophy at the Institute of Philosophy at the University of London. Nancy Cartwright, Professor of Philosophy at the London School of Economics and the University of California,

and Thomas Uble, Professor of Philosophy at Manchester University. Barry Smith, what's the basic idea at the core of logical positivism? How radical was it? This was very radical. Here we have the Vienna Circle, very impressed by science, by developments in logic and mathematics, especially developments in physics, say, but they're also very depressed by the lamentable state of philosophy. You have competing philosophies, metaphysical views about the nature of reality,

the ultimate nature of things, and these views are locked into a pointless dispute where you can't see how to make any progress. Now, the positivists in the Vienna Circle think, we've got to give philosophy a new job. It has to contribute to the advance of knowledge in the same way science and logic, can contribute. So they decide that philosophy doesn't have a doctrine to tell us. It doesn't have a

subject matter of its own. Philosophy becomes a method. It's a way of analyzing the statements and the logical structure of theories. It's a way of deciding which statements are statements of signs that are factual, meaningful, can be tested, and contrasting that with statements in logic and mathematics, which are true, not because we test them, but because they're true by definition. 2 plus 2 equals 4 follows from the meanings of the words that we use. Now, this new method makes philosophy largely about demarcating meaningful talk, which can be rigorously tested from the meaningless talk of metaphysics, which had pretensions to describe some sublime set of facts,

some transcendental reality beyond the ordinary. Now, this critique now becomes a critique of, language and no longer as it was with Kant, a critique of pure reason. Well, that's an excellent overview. Can you, can we just go back a little bit and tell us some of the people involved, how did they get together, did they discover that they had, what did they , well, obviously they discovered how this notion in common. Yes. So the beginning of the movement is really when in 1922, Morris Schlicht is appointed to Ernest Mach's chair in Vienna. And he gathers around him a set of scientists and mathematicians and philosophers.

very scientifically minded philosophers. And these are people who are ambitious. They want to make progress. They want to see how they can make a genuine contribution to the exciting ideas that are going on around them in physics, in logic and mathematics. They're impressed with Russell and Frege's attempt to reduce mathematics to logic.

They're impressed with the new physics of Einstein. And they say, these are people who are telling us something we need to know. So we as philosophers can't be locked in these pointless disputes. So really the kind of philosophy that had been going on where you make claims that are untestable, they cannot be decided, we don't know what sort of experiences we would use to tell whether or not one theory was true and another was false, they rejected them as meaningless.

Can you pick out one or two more people? You mentioned Schlicht. Can you give our listeners an idea of two or three other of the key figures we will be returning to in this discussion? Yes, I think the three key figures are Schlick, Karnap and Neurat. So we can see Schlich as the leading figure around whom the Vienna Circle gather. But more dramatic, I think, is the involvement of Otto Neurat. He's a sociologist, he's a social scientist, and he has a conception really of the movement that's taking place

as part of a larger social movement. He is interested in the unification of science. He's interested in a community of philosophers and science. is working together. In a sense, this is philosophy by committee, because you've got a lot of different views, but they're trying to figure out what they all think and what they share in common. In between them, you have Rudolf Carnap, perhaps the most influential figure of the movement. He is a superbly good logician. He is very inspired by the works of Russell, and he creates a way of rigorously testing scientific theories. So we're in Vienna, and we know what they're coming out of, and

We've got a few, we've got the main players there. Nancy Cartwright, can you give us some sense of the scale of what they were rejecting? Yes. Barry talked about them wanting to transform philosophy, but that's only a small part of what they wanted to do. I think transforming philosophy was a tool or possibly a side effect because they were interested in transforming society. These people had gone through World War I. Autonoir had observed. the ability to really regulate the economy and achieve the ends we needed to provide weapons and organize society to get all the munitions and food and clothes to the troops.

And they also noticed that there's not just the science of physics that was opening up and coming up with fantastic, fascinating new results. But there was a huge increase in skills and information in statistics. And they really did believe that with the proper use of scientific knowledge and social scientific knowledge,

one could transform society. So they were involved in a bigger enterprise than just transforming philosophy. The emphasis on clear thinking, exact formulation was going to be a tool to rid us of a kind of grand metaphysics that stopped social progress. They were opposed to religion,

they were opposed to what they called superstition. Their opposition to Hegelian philosophy wasn't just that it was nonsense, which they thought it was, since as Barry points out, you couldn't tie it down to anything. So can you just develop that a little bit about Hegel, just for a few moments?

They thought it was nonsense. Hague was nonsense. Right, why? They thought it was nonsense because you have grand ideas with very abstract, very loose terms, big claims about

the spirit of history marching forward. And when asked, if you try and think about it, what do these claims really tell us about real experience in the world around us? And the dialectical method doesn't they thought that didn't tell us anything?

That doesn't tell you anything. So they were, I think the important thing to start out from is that they were what in Britain we call empiricists. They thought the source of knowledge about the world around us had to be our interactions and our experiences in the world around us, and that our experiences and interactions in the physical world around us were the police for any further claims we made, that anything we thought we were talking about that seemed to make sense, but we couldn't tie it back to,

we're talking about, as Barry said, some transcendental or sublime views about the world. world, and that's supposed to be the world we live in. Now, what does, what support do those grand views have in our real experience and interaction with the world? And they said, when there's no support in real experience of the world, you not only can't decide whether what you're saying is true or false, you're not saying anything. So when you're having religious disputes and metaphysical disputes there, back to the word that I got from the notes from three, this is meaningless. Meaningless. It's not just that

it's not just that when you can't test it, you don't know whether it's true or false, it's that you think you're talking about something, and when you get down to it, there's nothing there. It's vaporous nonsense was the word that the English

positivists used. Although they were very different people and a brilliant group of people, there was a coherence about them, obviously, these Thursday the meetings for one thing Thursday, evening is not Thursday morning, anyway, and they lived in a part of Vienna called Red Vienna, and many were socialists,

many were Jews. Did their politics play in very directly to all of them or just some of them? Well, almost all of them were dedicated socialists. Schlicht is a bit of a border case, but they were dedicated socialists.

There was a lot of interaction with other movements in Red Vienna, there was a close connection between, you know, Karnap wrote a book called the Logisha Afbao, the logical construction of the world. And nowadays we talk about Afbao Bauhaus, because the Vienna Circle was closely associated with the Bauhaus movement and architecture. They were interested in Noirot was, well, Neurot himself had been the, there was a short-lived socialist government in Bavaria, immediately after World War I, and Noirot was the person who was the director of full social planning.

So he was going to employ these philosophical ideas, which had already been somewhat developed in an earlier set of meetings before the war, to organize all of Bavarian economies. So these people were deeply embedded with a kind of movement to improve society by clean lines, clear thinking, attention to the details of life and not getting swept away by religious views that kept you from

moving ahead in the right ways. Thomas Oval, the early 20th centuries we know about major scientific advances. Major scientific advances had happened before. Why was science so important in the approach of this group of people? Well, that is, on the one hand, the sort of biographical reasons,

as Barry and Nancy sort of said and you said in your introduction if they were straight philosophers they actually had scientific training I mean Schlicht did his PhD with Max Planck the doyen of the German physics yeah and Norad was a sociologist

Hans Hahn was a mathematician Frank was a physicist so they all had first experience of science and they knew how scientific knowledge claims were being established. And they contrasted that with philosophical knowledge claims and what they called the chaos of system and the anarchy of even philosophical terminology. So philosophy rather came badly off by comparison.

And it's also not just that science simply was sober and one knew. what was talking, but one was talking about. Science also made absolutely revolutionary advances, and that's why Einstein was of this central importance. His general theory of

or theory of general relativity, for instance, totally changed our ideas of space and time. Roughly speaking, space was no longer a fixed container through which time flowed, but there was a sort of a multidimensional space

time and moreover the structure of that was variable and was determined by the distribution of mass energy at the specific location, etc. So those were enormously revolutionary ideas and they came out of science itself and

Did they get nothing at all? Sorry to interrupt you. Did they get nothing at all out of what we might loosely call the philosophical tradition? From what Nancy is saying it seems they rejected it lock, lock, stock and barrel? Well, they were, as Nancy said, they were kind of empiricists. So in that sense, they felt a certain allegiance with, say, David Hume in a number of his sort of views. And they also, in their general approach, could be thought they wanted to renew the Enlightenment movement,

which they thought had sort of run out of steam. And now after, especially in those dramatic days after World War, after World War I, they wanted to renew that there because everything has. had to be built anew and they thought, well, let's do it properly this time. The phrase is how we know what we know. Was that the quest? That is how Herbert Feigel, one of Schlichtz, students once put it. He says there's a few basic questions which you always have to ask.

What is it that you think you know? And secondly, how do you know it? And ask this each and every time. And if you do that, you won't be led by the nose, so to speak. Can we take the person they challenged most, who seemed to be the first mountain they look back to, who was Kant, Emmanuel Kant, and an idea that was central to him,

which was synthetic a priori. Now, can you explain that to our listeners and why this was so heavily challenged? Okay, now, the synthetic a priori was Kant's attempt to answer problems of previous empiricism. There were questions for, instance, like everybody assumed that every event has a cause. But how do you prove that? You can't prove your basis of experiences only of events you have so far experienced. You can't, from that,

kind of generalize that into the future of all events. So one way out, which Kant took, is to say, well, look, on the other hand, on the one hand, this supposition that every event as a cause underlies all our thinking. On the other hand, we can't prove it on the basis of experience. Well, we must get it from somewhere else. It must be, as it were, a truth of reason that we bring to our experience. But it was a truth of reason that said something about the world. So it was synthetic.

It said something about the world. It had empirical content. But at the same time, it wasn't learned from experience. it came from within us, from reason. And in that sense, it was a priori. So that's a synthetic a priori. And what the, in the course of the 19th century, sort of continental philosophy kind of invented all sorts of synthetic a prioris

for different sciences, and some Neocantians invented synthetic apriorias for the social or historical sciences, et cetera. And again, the theorists of the Vienna circles, sort of said, what control do we, what cognitive control do we have over the postulation of those things? And they kind of rejected this and said, look, let's just go back to how we know we can gain knowledge, namely let's go back to the positive sciences. And there we have either empirical sources or we have logic. So we either have analytic truths or we have synthetic truths. The analytic truths are a priori. The synthetic truths are a posteriori. The synthetic

truths are a posteriori and therefore this third position that can't I outline trying to bring the synthetic and the I priora together. We don't need it. Barry Smith, can we develop that using the word verification as a key? Yes, sure. So exactly as Thomas said, you have this tradition of empiricism where all of our knowledge is derived from the senses. But of course, some propositions like the propositions of mathematics don't seem to come through the senses. We don't seem to base them on evidence and testing and experience. So the empiricists were rather stuck as to how to explain them. The move forward to make this logical empiricism is the idea that the truths of mathematics and logic are truths by definition, the truths in a system. So now you must ask of any statement,

is it meaningful? And it's meaningful either because it can be verified. And now we have a criterion for meaningful empirical discourse, for meaningful factual talk. Can these statements be verified? And by verified, they mean verified in a way which parallels that of scientific verification. Exactly. They mean by, we can verify a statement by observation or experiment. Basically, we must be able to tell what method would we go about using and employing to find out whether this statement is true or false. Now, there are statements that could be verified. Everything else was either a totology, a pure logical analytical... Can you give us a couple of examples? Give us an example. Give us examples of a statement. It can be verified. It can be verified. And then the other one. Well, suppose

you want to know whether the liquid in the jar is an acid, then you can verify it by testing it with litmus paper and seeing whether the litmus paper turns red. If you want to know how many coins are in my pocket, you can verify it by turning out my pocket and counting them. But if you start to say that all reality is one substance or all reality is a plurality of substances. We've no idea how we go about verifying that. That's not verifiable. Is it not? I mean, what's all this

particle research about that? Well, particle research is fine because you're using the methods of science, and the methods of science have to be ultimately confirmed by the empirical basis. You've got to look at the meter readings, you've got to use the mathematics. But if you're making philosophical claims which are supposed to transcend methods of verification,

then we don't even know what would make them true. So the verification criterion of meaning becomes the kind of key tool to go about analyzing which statements are acceptable and which are not. And of course statements about ethics, religion and so on are not verifiable. They become meaningless. A way to tackle this now at this stage in the discussion would be to ask each of you, as it were, to take place of one of the three key people. There are three of you here. And as you mentioned at the beginning of the program, we have three main persons. I mean, that's maybe unfair to the others,

but there's Schlick and there's Neurad and there's Karnap. So if you, Thomas, Will, can start saying what schlick, because we're not talking about cohesive group there and the logical positivists, but we know we're talking about different people going towards the same end. Can you tell us what Moritz Schlich, what his main drive and argument was? Well, Schlich, as earlier, sort of had a background in physics. He was one of the first philosophers in, everywhere really to write knowledgeably and, in fact, gaining Einstein's approval for that

about the theory of relativity for special and then the general theory of relativity. And in Vienna, he turned to larger-scale epistemological questions about the theory of knowledge. And amongst those three that you've just sort of mentioned, Schlicht perhaps was still the most traditionalist. So within these kind of revolutionary movement, he was the one who was sort of most, most betoken still to be. So how would he express that? And one could say that in, first of all, in how he himself thought of this new philosophy, he thought of that specifically of trying to make clear what we mean,

a kind of meaning philosophy as meaning analysis. But it was still a distinctive science. philosophy, whereas others like Neurat, basically, he didn't even like the word philosophy because he was so abhorred by the past pretensions. And then very specifically, they disagreed about what the empirical basis of our scientific knowledge actually was. And there, all three of them made different proposals, and they took different position in the course of a kind of a long debate that basically lasted the whole extent of all.

of the Viala circle. And Schlicht believed ultimately that you could gain knowledge through observation, which could be private, was private observation. That's right. I mean, they all believed that observation was the key to empirical knowledge, but he conceived of those of the basic elements of our knowledge as statements about the content of our phenomenal experience, what has given to us, what appearances we have,

which precisely, as he suggested, were private, and there are certain difficulties attached to that, which kind of unraveled his views. Sorry, I'm not very sorry about that. Nancy Carter, what about Otto Neurat? Where did, as you stand, is the wrong word? What was his drive? What was his contribution to this group?

Well, Neurat made two contributions, I think three. One was the political push, but the philosophical contributions were in the first place, he strongly disagreed with Schlich about what was the bottom line in science. He thought that this talk about our inner experiences was a dreadful mistake and that science always started with observations described in the language of physical objects. So it's not useful to say, I'm having an experience of a red thing. It might be useful to say the stoplight is red.

One's a statement about my inner experience and the other is a statement about a physical object in space and time. And it mattered because Neuhrat thought you could only build up science from these claims about physical objects and how they behaved in space and time. When you keep using the word science, and Thomas pointed out earlier that he rejected the whole notion of the idea of there being a philosophy. So philosophy didn't count anymore. It wasn't on his...

agenda. It wasn't on his agenda. It wasn't in his mind, as it were. But nevertheless, he made two huge contributions to the philosophy of logical positivism. And the reason Schlicht wanted to go back to experience was the nice thing about science is that it gives us a high degree of certainty. And if you begin to look for certainty, there's a natural progression to think, well, I could actually readily be mistaken about whether the stoplight was red. Perhaps I missaw it, perhaps the light was reflected in non-standard circumstances, etc. But you pull back and say, well, if I want some certain foundations for science, let's go back to something I can really be sure of. I have this red experience now. So it was one of the reasons for wanting to pull back into subjective experience as the basis for science was to try to find some basis that was certain.

And Neill thought that was absolutely mad that you could never build science from those kinds of propositions. So you can't build quantum field theory from reports of read here now, which was the kind of experiential report. And Barry, Barry Smith, Rudolf Carnap. Yes, Carnap comes in as the mediator

between these two other figures. So you're... You're sitting between these two. And I am. I feel like the mediator and I. I just told the listener of how carefully this program has been organized. It's been very well constructed. So we have this insistence that science is ultimately based on the private experiences and observations of the individual scientist. We've got Neurat talking about the public language describing physical objects and their properties.

One of the things I neglected to mention was that for Neurot, what was very, very important is something that we now stress about science is that it's a public enterprise and the vision of labor and that you really did need to have all these different activities by all these different scientists doing different jobs. That's true. That drove you to a physicalist language, a shared physicalist language. That's true. But of course, Carnap doesn't quite readily give up the idea that philosophy has a role. So he thinks the role it has is in fact to be a logic for describing theories and systems. And logic is supposed to give you rigor, clarity, sharp definition of concepts. This is a fantastically good tool to saying what precisely is my theory claiming,

how is it related to its observational evidential base. Now, Karnat at this point has a sort of conventional move to reconcile the other two. He says we could build a theory that's ultimately talking about as the evidence base experience, and the individual reports, but we could just as easily have a theory that talks about physical objects and makes that the basis and the evidential support for the theory.

And it's a conventional choice which one of these you use. If they can both deliver predictions and results, both will do. So we now introduce this idea that you've got competing theories. And another important point of this, he calls it a principle of tolerance.

He says, you know, you can build up your theory any way you like from the inside, and then you can ask questions about what follows in the theory, what is the theory claiming. If you stand back and you ask, but which of these theories is right or correct, now you're asking something quite meaningless. There are only questions internal to the theory, not questions, meaningful questions, external to the theory. Thomas Ebel, the Ludwig Wittgenstein visited the Vienna Circle in the 1920s. What did they take from him? Well, they took from Wittgenstein, who in 22, 22 published a famous book, The Tractatus Logico Philosophicus. It's probably one of the most austere philosophy books ever published.

And they stumbled across that and, in fact, read it in the group in meetings through a whole sort of academic year in 1925. and they found in that the key for the problem that made their positivism distinctive, as it also sometimes called, made it into logical empiricism. They found they're the key for solving the problem for how to account for our knowledge of logic and mathematics. Prior to Wittgenstein, still with Russell, logic was thought of as describing, as it were the most abstract laws for the furniture of the, universe altogether. What Wittgenstein introduced was the idea that logic itself was empty, tautologists. And the word empty here means it doesn't tell us anything about the world.

Logic tells us, for example, either it's raining or it's not raining. That is logically true. It exhausts the possibilities, but it doesn't tell us anything about what the world is like. And that was the job of logic. Logic was a calculus to allow us to build statements, it had formation rules, and then it had transformation rules. It showed which statements followed from others and which contradicted each other. And therefore, our knowledge of knowledge, so to speak, could what was trained or could, in some sense, be considered knowledge of truths of reason, but these truths of reason were precisely, again, not empirical. They were not truths about the world. And with this knowledge,

with this account of logic, they were able to say, well, look, we are good in purposes. We don't need to account for rational intuition to learn about numbers, et cetera, because they also believed, as Wittgenstein didn't, but they added that to Wittgenstein's idea of the tautologistsness of logic, that all of mathematics could be reduced to logic. That was a program of logicism they inherited from Frager and Russell. Barry Smith, can we turn to the area of language now? The philosophy became a critique of language and logic and not reality.

Can you unravel that place? They believe that there is a job for a philosophy to do, but it's the job of logical analysis. And logical analysis means that what philosophy amounts to Carnap thought was the logic of science. was this was the only job left for philosophy. So you look at signs as a set of claims, a set of statements trying to make hypothesis

about the way the world works, claims about what we observe. You have to make those claims rigorous, logically well structured. You have to show how certain observational statements are predicted or follow from theoretical statements. You have to show how internally consistent your theory is. So you're using a study of the meaning

of words and the meanings of theoretical scientific language to be the only philosophy that's left. It's logical analysis. Now this, of course, means that in areas like ethics, we're going to claim that ethical statements that it's wrong to steal money or it's good to be kind to one's neighbor, these are not empirically provable statements, nor are the logical totologies. So they end up being meaningless. But now what we can do is we can say, well, Let's analyze the language of ethics. Let's do a linguistic analysis and say, what does this ethical talk mean?

And they come up with a new view. In fact, Freddie A.J. A.R. comes up with a new view. That we shouldn't see ethical words as describing the world. We should see them as expressing our feelings. They're a way of indicating our attitudes and inclinations, our emotions, if you like. So stealing is wrong. It is not a fact. It's an opinion. It's an opinion, and it's an opinion I try to convince you of.

And A.J. A.R., who had this emotivist theory of ethical statements, developed eventually by Stevenson, says, we could just as well say, you stole that in a sharp tone of voice, or we could raise our eyebrows. So when we say it's wrong, we're saying, I disapprove. Or you're just saying that it's often called the boo hurrah theory. So you're saying, you stole something. Boo. Your kind. Your kind, hurrah. So this is the parody of the view,

mainly that when you utter it's wrong or it's right, you're just giving a thumbs up or a thumbs down to what actually happened. Can we just push this a bit further, Nancy? Can you give us an example of the sort of process, a logical positivist? There's no pure, like we know the different people. Three of you have expressed different views of the different people.

What would he go through to get, let's call it a secure starting point. I mean, the secure starting point for a theology would be a belief in God, that there is a god. That's a secure starting point. Aquinas would have, Augustine would have, that's where I start from. And similarly through other, you probably wouldn't call them disciplines, areas of knowledge.

What's a secure starting point for a logical positivist? Well, I'm sorry, but there are three positions. Secure starting point for Schleck would be a report of your own experience. That can't go wrong. Maybe you can't get very far, starting with that secure starting point, but how could you be mistaken that you are having a red experience now? You've just proved. You just said earlier you could be mistaken. Well, that's Neurat's view, and it's my view, but it wasn't Schlicht's view. So Schlicht's view that once you've retreated into subjective experience, it's secure.

The Neurot's view was that nothing is secure, that you. You have observation reports, and you have to use the language and the concepts that you have at the moment, and you have to use the methods that you have at the moment, and you have to make your bet about what are the best methods, and what are the things that you are most secure in. And he used this metaphor of we're like sailors, having to rebuild our ships at sea, and never able to put into dry dock and build from a firm foundation. So, Neumalt thought, you do have to have tests,

your claims and make them consistent with your observations, but you're never secure that your observations are right, and even your observations might have been wrong, and you've got to start rebuilding. So Noirot said no secure starting points, and as I understand Carnap, Karnap said, well, you can choose a set of claims

that you're going to hold constant for the moment and look to see what that body of theory is surrounding those, but the choice, it's more like the Neurav view, the choice there is going to be conventional. Thomas Schiabel, were traditional philosophers fighting back at this point, or did the logical positive just sweep away all of the systems? Did people say, something revolution has happened, we must abandon all traditional ways of thinking and join in?

No, they did sort of fight back, depending on what place and what, what time we're sort of talking about. In Austria and Germany for related sort of movements like the Berlin Society for empirical philosophy, they fought back by simply ejecting them, sending them into exile, if they were lucky, because political developments were such

that, you know, under Nazism, that kind of science-evidence-based reasoning was just utterly opposed by the authority. could contradict what they were sort of claiming. So the Viennese circle was... Was dispersed, dispersed. And it was partly, of course, the fact that a great

number of them were Jews hastened to disperselled. But it was connected to what they thought as well. Yes, and they were socialists. They weren't just Jews. They were Jews and socialists. And remember, they're sweeping away large tracts of German philosophy, which were very important to the Nazi ideology.

So that's what happened there. But What about France, for instance? Are they saying we're not having anything to do with this? Well, France, there was for a while sort of an opening for them. They had a very big international conference there in 1935, Unity of Science Conference. But the recent research suggests that, in fact,

Neurad, who was always the one who initiated these contacts, was talking to the wrong people, and they fell between the cracks of sort of international. Parisian intellectual warfare. So they didn't get too far there. But in England, of course, there had a spokesman in E.J. A.R., who somewhat simplified their sort of doctrines,

but certainly put it out. And Ayer, being, you know, promoting the doctrine with his useful sort of enthusiasm, obviously took great fight into taking on all comers. And then... And this helped establish an Oxford group, didn't it? Language, truth and logic was a... It resonated around...

It grew out of a, error went for four months to Vienna in 3233. He came back and began to gather a group of discussants in Isaiah Berlin's rooms in all souls. There was a core group of seven, a bit like the Vienna Circle, a core group of seven, that met weekly and discussed the ideas of essentially logical positivism, among other things. And as in Vienna, they all were progressive, left-wing. They tended to be anti-appeasement and were almost all of them involved in the labour government and a kind of socialist-leaning activities after the war. And to push on a bit, it went to America too as well, didn't it, Barry?

Yes, it did. I mean, when this dispersal, they literally went to America for refuge. Some of them went to the UK, some of them went to America. And again had a big impact on America. That had a huge impact. you have the view that becomes very prominent, I think, at that time in the US, that philosophy of science is philosophy enough, that if you're doing philosophy of science, you're doing something that's making a real contribution,

that other things should really fall away. You've got the development of logic, which Carnap continues to develop, but you've also got young philosophers of science coming through people like Quine, who set up a generation of new philosophers of science and create new problems, taking the ideas forward, disagreeing with what came before. But it's this that actually shapes what we call the Anglo-American tradition and especially the analytic tradition in philosophy. You mentioned Quine.

It's probably a simplistic. I'm not a sorry about this, but he, as it were, attack logical positivism, didn't he? He did, but I think you can't understand Quine unless you see that his attack is a way of cleaning the stable so that empiricism can go on. He thought they were mistaken. He thought they were committed to do. dogmas. He thought one of the dogmas was that every statement was either analytic and synthetic.

And he thinks, actually, this division between, you know, facts about the world and facts about meaning is not very robust. In fact, they bleed into each other. There's no clear distinction. And the other thing he rejects is the idea that we can ground our theoretical statements on observations and experience. He says that our statements must face the tribunal of experience as a corporate body as a whole. Briefly, I'm off. There's a lot more. say and I just tip of iceberg stuff but still can you briefly tell me what influence

you think this has had on sort as generally in since the 1920s and 30s Thomas Hugo well I think while it's not a sort of a live project in analytical philosophy now it very much

has set up its ideals of clarity and making testable justifiable at least knowledge claims and to render philosophy in some sense scientific. I mean, at the moment I think we see an analytic philosophy

still a strong sort of counter reaction to it. So 30 years ago, somebody said, well, logical positivism is about as dead a philosophical movement as it ever will be, but in a certain sense, it's sort of, they're sort of the living dead. On the one hand, they're still being invoked by contemporary philosophers whenever they want to put forward their current theories

as something which they reject and want to do better with. And on the other hand, much recent research in the history of analytic philosophy has shown that indeed what this program will have brought out, that the logical positivists were not

as homogeneous as they often portrayed, but actually give you this wide variety of positions, some of which anticipate it's later overcoming. Nancy Contra. I think that they were also part of a movement. I don't know whether they, I don't want to say they were the calls of it, but they were the spokespeople for a movement to scientize the study of society.

So that the idea that you were scientizing philosophy was only a part of it. They were scientizing the study of society. And they moved along with the idea that you could construct a better society by evidence-based policy, which is all the rage at the moment. And finally, in brief, I'm sorry, Barry, Parisma. Yes, I think they've changed the idea that philosophy has its own subject matter. Instead, philosophy is a second-order discipline.

It's the philosophy of science, of mathematics, of biology and so on. So we're making a contribution, as it were, to the methodology. We don't do work on our own to create new doctrines. Well, thank you very much indeed for bringing that down to us. I was a bit, to put it mildly, worried about this program. Thank you very much, Nancy Cartwright, Barry Smith. And Thomas Ewe will next week.

We'll be talking about the Eid Icarra, the Pre-Cambrian Life Forms, which vanished 542 million years ago, whether the earliest form of life. Thank you for listening. If you've enjoyed this Radio 4 podcast, why not try others, such as Thinking Aloud, where Laurie Taylor discusses the latest social science research. To find out more, visit bbc.co.uk forward slash radio 4.