In Our Time - Kant's Copernican Revolution

Episode Date: June 3, 2021

Melvyn Bragg and guests discuss the insight into our relationship with the world that Immanuel Kant (1724-1804) shared in his book The Critique of Pure Reason in 1781. It was as revolutionary, in his view, as when the Polish astronomer Copernicus realised that Earth revolves around the Sun rather than the Sun around Earth. Kant's was an insight into how we understand the world around us, arguing that we can never know the world as it is, but only through the structures of our minds which shape that understanding. This idea, that the world depends on us even though we do not create it, has been one of Kant’s greatest contributions to philosophy and influences debates to this day. The image above is a portrait of Immanuel Kant by Friedrich Wilhelm SpringerWith Fiona Hughes Senior Lecturer in Philosophy at the University of EssexAnil Gomes Associate Professor and Fellow and Tutor in Philosophy at Trinity College, OxfordAnd John Callanan Senior Lecturer in Philosophy at King’s College LondonProducer: Simon Tillotson

BBC Sounds, music, radio, podcasts. Thanks for downloading this episode of In Our Time. There's a reading list to go with it on our website, and you can get news about our programs if you follow us on Twitter at BBC In Our Time. I hope you enjoy the programs. Hello, in 1781, Emmanuel Kant shared his insight into how we understand the world around us, as revolutionary in his view, as when Copernicus realized it's not the earth that's at the center of the heavens, but the sun. Kant argued that we can never know the world as it is,

but only through the structures in our own minds, which shape our understanding. And this idea that the world depends on us has been one of Kant's greatest contributions to philosophy and still resonates. With me to discuss Kant's Copernican Revolution are Fiona Hughes, Senior Lecturer in Philosophy at the University of Essex,

Anil Gohmes, Associate Professor and Fellow and Tutor in Philosophy at Trinity College Oxford, and John Cullinan, Senior Lecturer in Philosophy philosophy at King's College London. John Kallanan, what do we need to know about Kant's life between his birth in 1724 and the date I mentioned

1781? Well, Kant was born in Kurnigsburg, in 1734 as you said, which is now Kaliningrad on the Baltic Coast. He was raised in a modest family and went to the local school and famously lived

in Kurnigsburg and worked there around there for the entirety of his life and never travelled. He showed a lot of talent for science and philosophy as a young student. And after graduating from the Albertina, the local university, he became a private docent, which is an unsalaried lecturer, a freelance lecturer for hire, students would pay him at the door. And he lectured for decades on a huge variety of different topics before he finally became a salaried professor in Konigsberg. He was writing throughout this time early on on matters of metaphysics, but also on science.

He was very educated on Newtonian science. He was interested in how Newtonian science might be integrated and merged with metaphysics traditionally understood, the examination of fundamental concepts such as space, time, substance, cause and effect. And he wanted to know how these traditional concepts mixed together with the new burgeoning science that had developed over the last hundred years with Galileo and Newton. He was writing works throughout his early life, not with a huge amount of success. By the time we got into the 1760s, when he's now around in his 40s, he's developed a somewhat ambivalent attitude towards the idea of metaphysics.

There are too many competing systems, too many of them are dogmatic, asserting different theories without showing that they actually apply to the world. And then finally, in 1770, he's around 47 years of age now, he gets offered a professorship in Konexburg. And we're talking about a man who lived a spectacularly uneventful life. He stayed in the same town on all his life. He went for his daily walks. He lived a bachelor life.

And so we can put the life to one side now. The life was the work. Yes, his life is lacking in dramatic events during this time. He's a very well-known figure in the town, a desired dinner guest and a well-known intellectual. His company is greatly sought after. But as he finally gets a professorship in Konigsberg in 1770, he starts to develop a more regular frame of life, taking his famous daily walks at the same time with a constant regularity, because he now thinks he's starting to put together the systems for a new way of doing philosophy.

We have the Copernican word in this, science. Why did science matter to Kant? Science was hugely important to him because he was a practicing scientist. In 1755, he wrote a theory of the so-called Kant-la-place nebular hypothesis, a theory about the origin of the solar system. He understands Newtonian physics at a very high level, but he understands that it's difficult to ground the fundamental concepts that science presupposes, the concepts of course. an effect that are required to make sense of Newton's law of gravitation, for instance. He understands that there has to be some grounding for science. But also, on the other hand, he sees that metaphysics has started to lose some of its credibility. It used to be considered, he thinks, as part of the scientific endeavor itself. It was all one large form of inquiry. But as time has gone on, it's lost that status. And part of his project that he's working on

all throughout the 1770s, where he publishes nothing, it's known as the silent decade, is a time where he's trying to develop a new scientific method of metaphysics that he thinks he can now reimagine the whole discipline with. And he brings that to publication in 1781 with the critique of pure reason. Thank you very much. Anil Gohms, can you introduce us to some of the background? What's a Descartes thought we could know about the power of reason alone? As John was just saying, the book that we're talking about is called The Critique of Pure Reason.

And one way to think about it is to think about a debate which is going on before Kant, about what we can use pure reason to figure out about the world. So there's this dispute in the history of philosophy before Kant about how much can we use our rational faculties, our pure reason, in order to discover truths about the world. And we sort of, in this cartoon way, talk about the rationalists versus the empiricists. And Descartes is one of the rationalists. The rationalists are the people who think. You can use your pure reason, you can sit in the armchair,

and you can discover really substantial truths about the nature of the world. So Descartes in his meditations thinks that he proves the existence of God and the immortality of the soul. And he thinks he can do all that just by giving you philosophical arguments. He's not going out and looking at the world and seeing what it looks like. Just by using his reason, using his rational faculties, he can discover these really quite substantial truths, the existence of God and the immortality of the soul.

On the other side, you get the empiricists who are really sceptical about this idea that you can use reason to discover these truths about the world. They're skeptical about this project of using reason to discover these kind of claims. They think you need experience if you're going to discover the kind of things that Descartes and Leibniz and Spinoza, the so-called rationalists, wanted to discover about the world. So in someone like Locke, for example, Locke thinks the mind is about. blank slate. You can't come to know things about substances, about causation, all those kind of ideas that John just mentioned to be really important to Newtonian physics. You don't get any of that knowledge unless you go out to do some investigation of the world. So reason by itself can't do anything. You need experience if you're going to figure out these truths. And in some way,

the most important philosopher on the empiric side is Hume. It's Hume who can't read and is blown away by some of Hume's arguments. And Hume thinks that experience is so important. Everything has to be traced back to experience. There's some of these ideas that philosophers talk about, like causation and substance and so on. We can't even make sense of them. We just have to get rid of these notions because we can't make sense of them on the

base of experience. So what you see on the empiric's side is a kind of clipping of philosophy's wings. The rationalists thought we could discover all these truths about the world just using pure reason, and the empiricists thought we couldn't. and then Kant arrives, and in a way he wants to be the referee in this debate, he wants to give you a principled way to decide when we can use pure reason to figure out truths about the world and when we can't. Is this a well-established, in the intellectual planet of the time,

is this a well-established demarcation between groups of philosophers all over Europe? It's something that we have now put back onto these philosophers, but actually Kant is one of the reasons why we start to carve these philosophers up in these kind of ways. He presents himself as writing his book in reference to the history that comes before him. So there's not a clean divide between them, but there is a very natural grouping between Descartes, Spinoza, Leibniz, people who thought Descartes thought you could figure out that God's existence, the immortality of the soul. Leibniz thought you could figure out the structure of the world, just using reason. And those philosophers like Locke and Barclay and Hume who think that experience is much more important.

Without experience, you really can't discover anything about the nature of the world. Kant came in and he saw both sides. Exactly. In some ways he wants to give you the best of both sides. Across all his philosophical works, Kant often feels the pull of two opposing directions. He thinks there's something really important in the rationalist idea that we can use our rational faculties to gain the really substantial knowledge about the world. But he recognises the force of the empiric's claim that how could you come to use your rational faculties to know about a world which was independent of you.

And he wants to somehow thread the needle between these opposing views and combine what's best in both of them, but also show how there's insights in both of them, but also they go, they're mistaken in various ways. Thank you. Fiona Hughes. What was Kant's goal in the critique of pure reason? Does the first line of that book help in the preface?

Shall I read it out? So you might not have it in front of you. He writes, human reason in one sphere of its cognition is called upon to consider questions which it cannot decline as they are presented by its own nature but which it cannot answer as they transcend every faculty of the mind was at the core of his problem i think it does sum up what he's about rather well and what he's claiming here is that we have a natural predisposition to to go beyond the evidence given an experience.

And yet there are questions we just have to try and answer, even though we don't have the grounds for doing so. And he refers to this as what he calls a natural metaphysics, which is characteristic of all of us, whether we're philosophers or not. So we go beyond the physical. We go beyond what is the case. What do you mean by that?

A couple of examples would be even in the most basic, even in counting objects in the world, counting is not something that can just be read off the objects that are out there. There must be some form of structuring activity that we bring into experience. And this is already a form of thought. Another example which may be slightly more easy to get a hold of is in the way in which we introduce moral principles into our experience. And for Kant, those moral principles cannot simply be found within experience. They have to come from something that we inject through our capacity for reasoning that John and Anila have already been talking about. So that's the way in which we naturally have a predisposition to move

beyond what is simply can be read-off experience. One way of thinking about this is that this is a two-edged sword. On the one hand, it has various benefits in that it means that we are capable of forms of self-reflection, that according to Kant, we have a capacity for freedom and morality, and even religious belief, because none of those can be explained in terms of what we can just read off experience. But on the other hand, it also leads us into making. unsubstantiated and indefensible claims about what we do not and cannot know.

And Kant calls this a natural dogmatism within the way we use our reason. What was his struggle for 10 years? What was the centre of the struggle over those 10 years, Fiona? Well, the centre of the struggle, in a sense, was trying to persuade his interlocutors that he could focus on and introduce the centrality of the mind within experience without reducing his account to subjectivism. And when he published the first edition of the critique in 1781, the immediate reaction was, on the part of many of his,

peers was that this was a subjectivism, that he was setting up a situation where the mind dictated what reality was. And his project was to try and establish that the mind was playing a necessary role within experience without coming to the conclusion that the mind created experience. Can we just, it's possible to summarize for the listeners, what his position was, what the core of this critique was? Sure, the mind introduces certain structures into experience, but the mind does not create the matter or content of

experience. So objects and their existence are not concocted by the mind. However, there would be no ordered, knowable reality, where they're not a certain input from the mind in structuring that reality. Thank you. John, John Kahneman, it can't identify Copernicus as a point of reference. What was the analogy who's making there? He makes this comparison with Copernicus in the second edition of the Critique of Purism that Fiona just mentioned, which he published in 1787. And there he's really making a kind of a sales pitch for,

what he's trying to do in the Critic of Pure Reason by suggesting that it's very continuous with the best traditions of science over the millennia. And he mentions Euclid and Galileo and then Copernicus, and he wants to suggest they all have something in common, which is firstly that they sort of bring their own theories to the world of experience, first of all. Euclid didn't go out and measure things

in order to discover the properties of triangles. he just constructed proofs. But then we can use those proofs to understand the physical world around us. So there's this thought that the mind brings things to the table that he wants to allude to when he's thinking about scientists. But he also thinks a second feature that is common in science

is making a radical change in perspective or a radical new way of thinking, as he puts it, in order to get a theory going. And sometimes that theory, that new revolution, and thinking is going to involve making a somewhat counterintuitive move in order that we can then later on see how it makes sense of things. So, for example, and the primary case is Copernicus, it seems as if the sun is moving across the sky, and it doesn't seem as if we here on the earth are moving. That's our ordinary natural judgment. However, if one makes a counterintuitive

of change in perspective and think that perhaps the sun is at the center of the solar system and that we are moving around it, then when you have that hypothesis in mind, you can then do more observations. As Anil was talking about, you can go to experience and agree with the empiricists once you have your theory in mind and then confirm your knowledge. So he wants to suggest that what we need to do in metaphysics to bring it back on track as a science is accept a certain kind of counterintuitive move at the outset, and when we do that, we'll be able to revolutionise metaphysics and interpret it in a brand new way that negotiates rationalism and empiricism.

So to put it very crudely, and I'm treading on a broken glass here, John, the world depends on us. Is that right? Is that what you're saying? There's an element in which that is exactly the counterintuitive move. We see the world around us, it doesn't seem like things depend on us, but there is going to be a sense, Kant says, in which the world fundamentally does depend on the mind. We don't bring the world into existence, as Fiona was saying, but we do an awful lot in transforming it and shaping it into a coherent, ordered, stable thing that allows us to go about our days. Thank you.

Anil, can you help us with some of Kant's language? What should we be told about analytic and synthetic knowledge? Sure, Kant's language is famously difficult and one of the barriers in some ways to understanding some of these ideas. The analytic synthetic distinction is a distinction that Kant introduces. He thinks this is a really important distinction that philosophers haven't recognized before. And one way to get a grip on that distinction is to think about it as a distinction between definitional truths, truths which in some sense just depend on their definition, and truths which go beyond definitions.

So here's an example. Let's think about the difference between all scarlet things are red and all the flowers in my garden are red. I mean, in some sense, it's just a definitional truth that all scarlet things are red. It's part of the meaning of scarlet that it's a shade of red. But it's not a definitional truth that all the flowers in my garden are red. It's not built into the meaning of the flowers in my garden that they're all red. So can think it's really important that we distinguish these kind of claims.

We've got to group together the claims which are just definitional, the ones where it's just the meaning of the words which explain why they're true, and separate them from the ones where that's not the case, where you need something beyond meaning, beyond definition, in order to come to realize that the claim is true. And in a way, this distinction is really important for Kant, because remember we're trying to figure out what we can use our pure, reason to discover what we can discover from the armchair. And I guess it was commonly agreed

by the rationalists and the empiricists that from the armchair, you can get definitional truths. So you don't need to go out and investigate the world in order to know that all scarlet things are red. It's not like we've got around and picked up all these scarlet things one by one and said, okay, that one's red and that one's red and that one's red as well. Definitional truths like all scarlet things are red, analytic truths. They're the kind of truths which you can get just by reflecting on the meanings of your concepts. Whereas the cases which are more interesting are what can't think of as the synthetic claims, the synthetic truths,

the ones where you can't come to know them just by reflecting on the meanings of the words involved. You need something else. Thank you, Fiona. Fiona Hughes, can we stick to the language here? What it can't mean by a priori and posteriori? The a priori literally means what comes first. But going beyond that literal sense to what Kant means,

he means that the a priori comes from the mind and not experience. In contrast to that, the a posteriori is literally again what comes afterwards. And what he means by that is that the a posteriori is given in experience. and cannot be derived from the mind. It has to be found within experience. To go back to what I said a little bit earlier about the a priori, when we started to talk about what the mind introduces into experience, the a priori, I think the best way of understanding it is as a structure or a framework

which the mind brings to experience. The a priori thus provides a structure for the experiential content within experience, the a posteriori. It's not that we first of all have an idea and then we go out and find it within experience, but rather that we're always already using that structural framework. And we also have a capacity for concepts, which again, it's not that we have the concepts before we use them, but rather that we have a capacity to order things through concepts, through words, through terms. Can I come in on this point? Everything Fiona says is exactly right.

But think about that contrast between all scarlet things are red and all the flowers in my garden are red. All scarlet things are red is a definitional truth. It's an analytic truth. But can also think you can know it a priori. You don't need experience in order to come to know it. Whereas to know that all the flowers in my garden are red, you do need experience to come to know it. So the kind of example I gave you,

but already it makes it look like the analytic and the apollary ori go together, and the synthetic and the apostory ori go together. And what Kant wants us to see is that, although most of the analytic cases are a priori, and the synthetic and aposteriori cases go together, actually these categories can come apart. And the really interesting case he thinks

are the synthetic claims which are also known apriori, the claims which are not just definitely, but we can know them without going around and investigating the world. That's why the a priori operates as a framework for the a posteriori. But I would still say that the a priori, although it can be established independently of experience, it doesn't have any validity for Kant unless it is applicable within experience. John Kallan, we've got some of the building blocks now. Can you tell us something about causation and why it's so important?

Causation is a real central case for Kant, and it's at the heart of the critique of pure reason. As Anil was talking about earlier, Kant's reading of Hume shook him, but also provided him with a lot of materials for what he thought were the solutions and the responses to Hume's own skeptical conclusions. Hume was an empiricist and thought that everything was derived from experience, so it looks like everything is. going to be a posteriori then in the way that Fiona's been talking about. But if you take that approach, it emerges Hume thinks that the concept of causation lacks any kind of objective validity. We have, in experience just simplifying one thing after another, what we don't have is a sensation of some things having to be connected in a certain way, which is the very idea of causal effect. And so he wants to say that it must be that the concept of cause is just perhaps something that we project onto our experiences after a certain amount of custom and habituation and conditioning.

And so that it's relatively arbitrary how the concept of causation comes about and how it's used. Now, Kant wants to oppose that and he wants to say it's in fact it's not true by definition, Hume pointed out as well. So it's not going to be an analytic truth that for everything that happens, there must be something that caused it to happen. It's not part of the definition of event that it has some preceding cause. But it's obviously true, Kant thinks, that if anything happens, it must have some preceding cause. So he wants to figure out how could this be? And he takes a lead from Hume by suggesting that it is part of the mind structure, that it brings a general rule, cause and effect, if something happens, there must be something that caused it to happen.

It brings it to experience. It brings it to the table, so to speak, in order to make our experience make sense. He suggests that if all our experience were just sensation, then it would be what William James later called blooming, buzzing confusion. There's way too much sensory information, and we'd never have an ordered, stable experience. Thank you. Anil, can you?

pull this together to explain what Kant's Copernican revolution is? Let's give it a go. So, I mean, in some ways, the Copernican revolution is the solution to a problem. So if we want to understand what the Copernican revolution is, we need to be clear about what the problem was that Kant was trying to solve. And we've talked about that already, that Kant was trying to figure out how you can use pure reason to find something out about the world. But given what Fiona's just said and what...

I was saying about analytic and synthetic before, we can now rephrase the kind of question that Kant is interested in. So he's interested in what pure reason can tell you about the world, and that means that any knowledge you're going to get in that way is going to be a priori. So he's interested in kind of a priori knowledge. But he's interested in substantive truths about the world, not really definitional truths, but much more interesting truths than that. So he's interested in synthetic knowledge. And so he tells us that the problem he's interested in can be rephrase there's the problem of how is synthetic a priori knowledge possible. So John's example of every event has a cause, Kant thinks as both synthetic and a priori.

He thinks it's synthetic because it's not a definitional truth. It's not a definitional truth that every event has a cause. But it's also not the kind of claim that one discovers by going out and investigating the world. So it's got to be a priori. And that's what Hume found so puzzling about every event has a cause. I mean, if it's a priori, then it can't be justified. by experience. But if it's synthetic, if it's a substantive truth, then it's not a merely definitional truth, so it's kind of not justified by logic either. And so what Hume does is

says, well, look, if every event has a cause, if that's not a definitional truth, and if it's not a truth that you go out and discover by investigating the world, then Hume says, commit it to the flames. It contains nothing but sophistry and illusion. Hume wants to say these claims need to be got rid of, right? They're just not justified at all. As a Kant's Copernican Revolution is meant to be a way, a solution to that problem, a way of explaining how it is that we could have knowledge like every event has a cause, which is not just definitional, but not the kind of knowledge you get by going out to investigate in the world, a priori knowledge. So how is the Copernican Revolution supposed to help, right? Why does

this help us at all? And what John and Fiona have been saying is that if we're responsible for the nature of the world, if the world in some sense depends on us, if we impose a structure on the world. Then it starts to be less puzzling how we could know about that world without investigating it. And the analogy with Copernicus is really important and appropriate here, because pre-Cupernic and astronomy assumed that you were fixed. And when you looked up in the sky and you saw the planets moving, what you saw was the real movement of the planets. And then Copernicus comes along and says, no, what you're seeing are not the real movement of the planets, but just the apparent movement of the planets. And you have to explain the apparent movement,

by you doing something, you're actually moving as well. And in a way, Kant thinks that pre-Cantian metaphysics is like that, everyone thinks that you're fixed and the objects you see are the real objects and you're not contributing anything to them. And he wants to take this Copernican move and say, actually, what you see is partly dependent on you. So the Copernican revolution is a way to recognize that we're imposing something on the world, and that explains how we can know about it, April, or I.

Thank you for you. Can you tell us more about the distinction between appearances and things in themselves? The idea of appearances follows from this idea of the Copernican revolution, in that objects have to fit with our minds, or more precisely with the structures that our mind introduces into experience. So Kant talks about objects as appearances. what he means here is that this is a model of understanding what objects are, that they must be both external to the mind and accessible to the mind.

So they appear to us, they are accessible to us. Now, this is contrasted by Kant with what he calls things in themselves. And he believes this to be the prevailing dominant paradigm held, he thinks, by both rationalism and empiricism, which assumes that objects don't have to stand in any necessary relationship to the mind at all. Objects understood as things in themselves are in principle, inaccessible to the mind,

and unknowable to us. Looked out more closely, things in themselves are not so much a special class of objects, but rather a way of thinking of the way in which the practical or the physical or the moral comes to bear upon our experience and cannot be known, but nevertheless is crucial for our experience.

So the examples would be of freedom and God. John, von Galan, what do you think is most innovative about Kant's approach? What do you think? Kant's really radically innovative way of doing philosophy is by taking traditional concepts like causation and substance, which you would think are features of that world independent of us,

the world of things in themselves that Fiona was talking about, and reimagining them as simply operations of the mind. That's an entirely new way of thinking. And similarly, no one before Kant had thought that, many had thought that we have different concepts that we dream up for ourselves or that might be functions of the mind. but no one had thought that they go so deep into the very structuring of what we perceive in our experience, as like Kant was suggesting. So that suggests that the mind is deeply interwoven with our sense of reality. And that's a hugely radical notion, one that is disturbing for many.

The writer and playwright Heinrich von Kleist had a crisis upon reading Kant when he thought that Kant has shown us that we have these green spectacles that we can't remove and that block off fundamental reality from us. And he thought that this was a terrible disaster if Kant's philosophy was true. However, I think Klyst misunderstood the other great innovation that Kant was making, which was that he was examining the question, what is objectivity? We might have thought, naturally, that you have a thought or a representation as objective, when your mind reaches out and that representation matches up how things are in themselves independently of us.

But can suggest that's not needed at all, that we can have a very good working notion of objectivity by staying within the domain of the way that we represent things. There are ways that you and I might see the colours of things that might be different if one of us is colourblind, but we're all going to see things as spatial, as temporal, as engaging in causal connection. connections with other things.

And this is part of the basic fabric of the human mind that everyone must experience in the same way. And he thinks that's a notion of objectivity that's good enough for the scientists and it's good enough for the metaphysicians. Anil, Neil Goams, Kant's been looking at the limits of human knowledge. Where does that leave God in his scheme? God is very important at the time in which he lived.

Where does it leave him? It's a really important question. Because part of what Kant is doing, wants to do is set a limit to the kind of things that we can know about the world using pure reason. So there's a kind of really positive aspect to what he's doing where he's arguing against him and saying, look, we can know that every event has a cause because the mind structures the world in some way. But he also wants to say, look, there's a limit to how much you can know using your pure reason. And against people like Descartes, he wants to say, no, there's a

boundary beyond which you can't use your rational faculties to discover truths about the world, about the nature of things. And in particular, he wants to draw that boundary just where the Copernican Revolution says it should be drawn, which is with experience. So it's all right to use pure reason within the bounds of experience. That's the kind of good aspect of pure reason, but you can't use pure reason outside of experience. That's when you go too far. And so think back to Descartes in the meditations proving the existence, of God and the immortality of the soul, Camp thinks that God and the soul are not the kind of things that you can have experience of. So that's a case where you can't use pure reason to

discover the existence of God, to prove the existence of God, to prove the immortality of the soul. That's going too far. And for some of his contemporaries, they called him Kant the all-crushing because of the way in which he seemed to knock down these arguments for the existence of God. But in fact, Kant himself didn't think this was bad for religious belief. So even though he wants to draw a limit to knowledge and say, you can't know that God exists, you can't use philosophical argument to prove that God exists, you can still think that God exists. It's all right to think that the soul is immortal.

It's all right to think that we're really free. So even though you can't know these things, it's all right to hope that they're true. It's all right to have faith that they're true. So famously, in the second edition of the first critique, Camp writes, I had to deny knowledge in order to make room for faith. Can I come to you again, Fiona, with a quotation. Kant wrote, thoughts without content are empty. Intuitions without concepts are blind. How does this relate to what you've been talking about?

First of all, just to make sure that we know what he means by intuitions, by which he means the sensory intake, which is, a compliment to our capacity to understand and order things through concepts. So the quote that you've just given to us, Melvin, what he's saying is that if you just have thoughts and they were just thoughts alone, then they would be empty and meaningless if they didn't refer to something outside of them. But on the other hand, the sense. would be just chaotic, like John was saying earlier, the blooming, buzzing, confusing, without concepts to guide and order it. So you need two sides. But to look at it a little bit more

even further, what he goes on to write immediately after that is that it's just as necessary to make concepts sensible as it is to make intuitions intelligible under concepts. And what this suggests is that this is that this is a sense. some sort of unification between concepts and intuitions or sensory intake that is required if we are to have knowledge. And the interesting and very challenging task that Kant sets for himself and for those of us trying to understand him is how it is that the conceptual side and the sensory intake side can be unified without reducing one side to the other. so that concepts become a species of sensory intake,

or sensory intake becomes a species of concepts. And that's exactly what he's trying to do, because as Anil was saying earlier, he's trying to give us the best of all worlds, or the best of two worlds, including the strengths of rationalism and empiricism. John Kahn, can we take a look at the impact of this? Did anyone agree that Kant had pulled off a philosophical Copernican revolution?

The impact of Kant's thought was, surprisingly quick and immediate and strong. He wrote the book in 1781. By the mid-1790s, there are journals set up dedicated to his thought. There are Kantian professors in various universities in Germany. So his thought has become indicative of German philosophy in general. But at the same time, there's a range of really remarkable thinkers in the next 25 years who are taking Kant's thought and developing it. Indeed, in the next hundred years, a range of thinkers will also be doing this, often adopting a slogan back to Kant. Kant has this unusual legacy that a lot of thinkers after him feel that they are the ones who need to complete Kant's system,

that Kant got some things right but didn't get it right, and that they are needed to take some element of it and drive it forward. The main thing that most of these thinkers have in issue with is the division between appearances and things in themselves. Yacobi, a contemporary of Kant's claims he can't live, he can't get into the system unless he accepts this distinction, but the distinction is intolerable and he has to leave the system afterwards because of it. It's absolutely vital that Kant has this distinction. Our minds don't bring reality into existence. That is explained by things in themselves. But he's also said that the limits of what we can know and understand is set by appearances. Now this puts them in an immediate difficulty. How do I even know that

there are things in themselves? Can I comprehend them? No. How do I even cognise them or know them with a lot of difficulty? And so it seems to many that things in themselves are an intolerable part of his system. And a lot of the thinkers afterwards, such as Hegel and Fichtha and Schelling, are trying to take Kant's view that subject and object, mind and world, are interconnected and even interwoven in ways that hadn't been appreciated before, and Kant is correct on that, and we need that kind of Copernican turn being made. But they want to develop the system in different ways without the burden of things in themselves as part of their philosophies.

That is actually something that's really a hot issue in, philosophy now, or at least philosophy, particularly when taken somewhat beyond the boundaries of mainstream academic philosophy. One is by a movement called speculative realism. In a nutshell, we need to return to the thing in itself, that we need to get beyond this anthropocentric view of the world that was initiated by the Copernican Revolution, and that this will be useful in all sorts of for instance, taking into consideration non-human animals and even inanimate beings. But at the same time within mainstream continental philosophy, phenomenology, which started at the beginning of the 20th century with Husserl,

insists that we have to start where the mind encounters the world. My colleague Adrian Moore likens Kant to the node in a letter X, that in some ways he synthesizes everything which comes before, And then everyone comes after Kant feels like they have to react to what he's saying. And like John said, sometimes they're thinking that Kant doesn't go far enough. Sometimes they're arguing with his very starting assumptions. But in a way, he sets the framework in which all the philosophers after Kant approach the questions that they're interested in. And one particular thing, which I guess is really important in philosophy after Kant,

is that Kant is interested in this question of how we can use our rational faculties, what we can do with them, when we can gain knowledge with them, or when we can't gain knowledge with them. And that question becomes really salient in philosophy, because in some ways the question Kant is asking is about how we could do philosophy at all. I mean, philosophers tend to sit in their armchairs, but they think of themselves as not just coming up with definitional truths. And so Kant is raising the question, how can you do philosophy? I mean, if philosophy is not just definitions, but it's not an experimental science, how is it possible to do philosophy at all? And that kind of self-consciousness about philosophy itself is a feature of Kant's work.

And through Kant, it becomes a feature of philosophy post-Cant. People have to reflect for themselves. What are we doing when we're doing philosophy? Well, thank you very much. Thank you very much, Fiona Hughes. Anil Gohmus and John Kallan, and to our studio engineer, Sue Mayo, next week, it's Charles Booth's landmark investigation of poverty

and its courses in his great survey of Life in Victorian London. Thank you for listening. And the In Our Time podcast gets some extra time now with a few minutes of bonus material from Melvin and his guests. What did we miss out that you would like to include? Can we start with you, say, Anil? One thing which I guess we didn't talk about, which is really central. Fiona mentioned it, is Kant's idea of freedom. So we have this distinction between appearances and things themselves, between the way things appear, the world of science and the way things really are. And one reason why that's important for Kant is because he wants us to, he wants to make sure that our freedom, our capacity to be free, is compatible with determinism in the empirical world with the idea that everything has a cause. And the way he does that is say, well, look, it's true that everything has a cause in the world of appearances.

But it's compatible with that that I'm really free as a thing in itself, myself. myself as I, in reality, outside the world of appearances, that's where my real freedom is. And that's hugely important for Kant's moral theory. In a way, one of the things which is driving the whole critique is the idea of fitting ethics and moral philosophy into the world as it's discovered by science. So nature, the empirical world, is all structured in the kind of way that the mind structures it in terms of causes and substances and so on. But in the world as it is in itself, freedom's possible. there. So the whole structure of the Copernican revolution leaves open the possibility that we're really free. And without that possibility, morality would be impossible. That's really

very clear the way Anil has put that. And it does open up this question again of what the status of things in themselves are. It does consistently say, as Anil has been suggesting, that this phrase refers to freedom, to God, also to the immortality of the soul. And that is one way in which the thing in itself has a certain role within Kant's philosophy. But as John was also mentioning earlier, it's also possible to see things in themselves as being the ultimate reality, the ultimate but unknowable reality against which we have to understand appearances, so that necessary background that makes them extramental. But there's a third way in which we can think about things in themselves.

And this is where Kant introduces the idea that they, he calls them, limit concepts. And the way I understand that this is that things in themselves can operate. They're a way of talking, which operate. huristically in order to make us aware of what it is that we cannot know. So they set out the limits. And that's not just a negative notion because it's extremely important to be able to recognise what we can't know in order to be able to justifiably make claims to knowledge in contrast to that. I think that's right. I think that it also goes back to what Neal was saying previously about how Kant makes philosophy a more self-conscious endeavor, in that it is,

it has its goal both to determine what we can know and also to determine the limits of what we can know, which is an additional burden that lots of other sciences don't have. They've got to be doing, philosophy has to be doing inquiry into substance and causation and number, and also has to be doing inquiry into the very limits of philosophy itself, which is not an easy task. But I think he brings to metaphysics the idea that it needs to be disciplined, so it doesn't engage in kind of random arbitrary model making, but actually shows some grounds for how it can be applied to reality. But it's, it has to do it for itself. Philosophy has to discipline itself. It has to It has pure reason, but it has to do a critique of that pure reason to show that here's my metaphysical model and here's how it applies to the world.

And that is a very demanding, but I think, meritorious picture of philosophy that you've got to earn your keep and show that this stuff works. And I think that's really important. And it picks up on what Fiona was saying about the first line and how important that is. Because one of the things Kant wants to do, he doesn't want to give the, he doesn't want to give the, impression that philosophy is over once you've written the first critique, as if we could just read it and then all the problems have done away with. Because he thinks that these questions come up again and again, and human reason always tempts us to go beyond and make these claims which go beyond the bounds of experience. So it's almost like philosophy is a constant thing. One

has to keep on doing it and reining oneself in from going beyond the kind of claims that one's going to make. So it's not that the critique of pure reason finishes philosophy, once you've read it, everything and stop. It's that even once you've read it, by the natural power of transcendental illusions, you're going to be pushed to try and say things which go beyond the experience to make these claims about God and the soul and freedom. And you're going to have to remind yourself that you can't do that and bring yourself back in again. So it's always an ever-evolving process. It never finishes. Yes, I really like that. And I think that it also, the way he begins the first edition,

talking about this natural predisposition to go beyond experience, this natural metaphysics is very interesting because of course Kant was a rigorous philosopher and he set up an extremely rigorous and demanding system. But at some level he also wants to say that this capacity for structuring the world is something that all of us as human beings are capable of. Perhaps only philosophers are capable of fully understanding what this structuring process is, but pure reason is something that belongs to all human beings insofar as they have capacities for conceptualising and also taking in things through the senses.

So that element of Kant can be recognized. as describing not just philosophers, but all of us, even when we're not philosophising. I think that's a really important aspect of Kant's thinking. I think in his earlier pre-critical self, he thought that understanding the concept of causation, say, required a lot of intellectual effort and reflection and hard work with the books. But the critical Kant seems to say, if you're able to perceive the world, you're using the principle of causation in your experience, you know everything there is to know just by seeing a ship move downstream or a ball rolled down a hill, then you're using, you have a good grasp of the

concept of causation, and that's something that's open to everyone, not just to philosophers. Is there any way you could, is there any way you could say his ideas are being developed today? I mean, in some ways, the problems that he gives philosophy are ones that philosophy is still wrestling with. So Kant thinks of what happens. before him as people sometimes being tempted into skepticism and thinking that you can't discover these substantial truths about the world or is going too far and using their kind of rational capacities and going beyond what they should say. So there's a kind of seesaw where people are going back and forth and he's trying to bring that kind of seesaw to an end. But of course what you see after

Kant is the seesaw carries on. So in the kind of immediate reception of Kant in Germany, the people that John was talking about, they're making the kind of claims which he would have thought as the kind of metaphysics which he just told you shouldn't be doing. And then, of course, immediately after them, you get people moving back to the kind of skeptical side and much more empiricist than trying to say, well, actually, maybe philosophy is only about definitional truths and we can't go beyond these definitions at all. So the same kind of back and forth that Camp thought he'd brought an end to carries on afterwards. Yes, and very much I think also with somewhat ironically with the concept of objectivity that he introduced,

which was there to try and bolster the sciences and show that it had a good meaning if we just restricted it to the world of experience and detached it from the idea that we need to get to the realm of things in themselves. But critics after Cantors are now thinking that the concept of objectivity is up for grabs. and maybe it is determined by us, but maybe not in the highly scientific way that Kant did. Perhaps it's something the concept of objectivity is developed socially and historically, over time, as Hegel argued. Or who knows, maybe it's a product of political forces like class consciousness, as Mark said.

Or maybe the concept of causation is generated by the ego to control the idds desires, as Freud might have argued. And now we have the whole problem, the whole question of objectivity is problematized in a way that I think Kant would be horrified by, but that he certainly inaugurated by detaching it from this deep kind of metaphysics in the first place. I agree with all of that.

But I think that Kant leaves us with an ongoing standard, which is to not give up on objectivity, but to recognise that mind plays part in it and he's there as a constant reminder even in the face of these swings from one side to the other that Anil was talking about. Well, thank you all very much. I'm sure a lot of people will get a lot out of that. I certainly think. Thanks very much.

In our time with Melvin Bragg is produced by Simon Tillotson. The system. A new six-part thriller from BBC Radio 4. What do you want to do with your life? Do you want to spend your time glued to a screen, feeding the dopamine addiction you don't even know you've got, looking at pictures of things you'll never have, places you'll never go, and people you'll never meet. Or do you want to exist in the real world? Do you want to be part of something? Do you want to use your body, the only body you'll ever have, gifted to you by millennia of evolution?

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