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Key Philosophical Texts in the Western Canon

recommended by Nigel Warburton

Even if you've never studied philosophy, it's nice to be able to read a few books and get a sense of what it's all about. Here, we asked our philosophy editor, Nigel Warburton, to talk us through five key works of Western philosophy—many of them in the public domain and available for free as ebooks—and explain why, despite one or two odd conclusions or quirky writing styles, they've played such an important role in expanding our understanding of the world.

Interview by Sophie Roell, Editor

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We’re going to talk about five key philosophical texts in the Western canon. First off, how have you chosen them?

Obviously, the history of Western philosophy includes thousands of books and to narrow it down to five is ridiculous. But I’ve chosen books that I think are incredibly important and not too threatening to read if you haven’t studied philosophy formally. These are books which are classics, undoubtedly, and repay reading at the level of ideas but have some kind of literary merit as well.

I should stress that these are choices from a history of Western philosophy. This is a tradition that stems from the ancient Greeks but has certain points of contact with Eastern philosophy. They’re very much within the core canon. They’re all male authors, which reflects, sadly, the history of philosophy up until the 20th century, dramatically skewed towards male writers for all kinds of sociological reasons that have nothing to do with women’s ability or potential to write great philosophy. There have been some great women philosophers, but if you had to pick only five books it would be tokenism to choose a book above these, I feel. If you’d like to find out more about women philosophers, I recommend The Philosopher Queens as a good place to start.

Let’s go straight to your first choice, which is Plato’s Republic. Why is this a book that’s worth reading?

It’s obviously a foundational book in the history of Western philosophy and of political thinking as well. It’s written as a dialogue, but it doesn’t feel much like a dialogue, at times. In the book Plato, the author, includes Socrates as a character, and we assume—because Socrates was Plato’s teacher—that it gives a reasonably accurate picture of the kind of thing that Socrates said. But, at a certain point, the views are very much Platonic, rather than Socratic.

It begins with a discussion about a fundamental question about ethics, basically why anybody should behave well. Anyone who had a magical ring which he or she could put on that made them invisible, surely they would just take advantage of other people? It’s only because of the risk of punishment or because powerful people stop us doing things that we don’t behave immorally most of the time, one of the characters suggests. The overall arch of the book is to suggest No, that there is a reward of acting well, there’s a psychological health which is achieved when the three parts of the soul, or as we would say mind, are in good balance.

Now, that doesn’t give you any idea of why it’s called Republic. But, actually, the way that Plato develops the argument is by likening the well-balanced mind to a well-balanced city-state, in which you have philosopher kings or queens at the top, trained in a particular way so as to be unbiased. This is the rational part of the soul. You have workers at the bottom, doing the dirty work, and a kind of drone/ guardian/soldier class in the middle. This is supposed to reflect the well-balanced mind, but actually is a model of the state. And, so, Plato presents in this book a theory about an ideal state, an ideal way of organizing society, where because power corrupts, you have a special kind of incorruptible class at the top, a class of people who can see more deeply into the nature of things and aren’t sidetracked by mere appearances.

“I’ve chosen books that I think are incredibly important and not too threatening to read if you haven’t studied philosophy formally”

It’s at this point that Plato presents one of the most famous thought experiments in the history of philosophy, the analogy of the cave. The cave is where people are chained facing a wall and they see flickering shadows on the wall. But they don’t realize these are shadows, they take the shadows for reality. In fact, they’re shadows cast by objects being held in front of a fire behind them. And then one of these chained people escapes and goes outside and sees the real world outside and the sun and realizes that everything else is a mere representation at several removes from reality because it’s a shadow of a silhouette—and tells people about the reality that’s out there.

This image is supposed to show us how philosophers, by the power of thought, reason about the abstract ‘Forms’ and not just the appearances of things. Most of us are like the people chained facing the wall, taking appearances for reality. But philosophers reason about the perfect versions of things. So, if you think of a circle, any circle that you look at is an imperfect circle. But we have this idea in our minds of a perfect circle, where every bit of the perimeter is precisely equidistant from the center. That ideal doesn’t just exist for circles but for things like tables: there is, for Plato, an ideal table, or an ideal person. Everything has an ideal Form. And, according to Plato—in this metaphysics that he presents—the role of the philosopher is to think about those abstract ideas.

The Republic is a mixture of metaphysics, political philosophy, and a kind of psychology about the balance of the different parts of the soul. Many of its ideas have subsequently resonated throughout the history of philosophy.

I remember the philosopher Jonathan Glover, in his Five Books interview on moral philosophy, being quite critical of the Republic. He said it contains “a tremendous amount of nonsense about what the ideal society would be like. But it is an unmissable book because of Socrates. He invented the method of doing and teaching philosophy that has never been improved on”. Do you agree with that?

Certainly that’s true of the opening of the book. There are some very challenging ideas in there. Karl Popper famously described Plato as a totalitarian thinker, because his ideal society is heavily censored, for instance. Plato says you shouldn’t have the arts because the arts deal in fictions which are prone to make us have the wrong kinds of emotions and give us a false picture of reality. So turn away the artists at the borders of your state, because they’re going to corrupt society.

You also have this fundamental lie at the heart of society where you tell people that the reason they occupy a particular stratum in society is because they have a certain kind of metal in their soul. If you have the right metal, you get to be higher ranking, if you have the wrong metal, you’re lower. These are kind of lies which keep society in place. It’s awful.

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There’s a famous critique of democracy there as well, where Plato famously likens democracy to a ship being steered by all the passengers, rather than having a skilled pilot at the helm, which is what you need in a storm.

There are, then, lots of things about the content of the Republic which are controversial or wrong—including the idea at its heart, the metaphysical approach which suggests that there are these discoverable forms for everything, and that appearances are fundamentally deceptive about the things that matter.

Nevertheless, the book is really stimulating for all kinds of reasons, not least because of something I strongly believe – that the best philosophy books are the ones with which you can disagree, and which it is easy to disagree with. They stimulate you to thought. Also, there’s the importance in the history of ideas of these idealized versions. If you think of painting, in the Renaissance there’s a kind of Neoplatonic view about beauty where some artists are trying to represent the Form of beauty, not a particular beautiful person. That’s got a fairly direct link back to Plato’s ideas about the Forms, that we can abstract from some particular beautiful person and get to this perfect circle version of them, as it were.

Shall we talk about Descartes and his Meditations next?

We’re jumping from the fifth century BC right forward to the first half of the 17th century. René Descartes is a superb writer who, in his first Meditation (which is the one I’m recommending) takes skepticism—which is an unwillingness to assume anything, a philosophical stance where you question everything—about as far as it can go. Meditations is written as if he is going through a process in real time, he’s imagining himself sitting by a fire taking all the thoughts that he’s had in his past, the different ways of acquiring information, cross-questioning himself about whether he could have been deceived about any of those, and employing what’s come to be known as ‘Cartesian doubt’. It’s not taking as true anything about which there is the slightest possible doubt. In ordinary life, that’s not a way to behave. If I take a step, the floor could always give way beneath me, I can’t guarantee that it won’t. But on Descartes’s view, if there’s the slightest possibility that it might give way, then I shouldn’t take that step—or at least shouldn’t treat my belief that the floor is firm as an example of a foundational belief. That’s a strategy for once in a lifetime, of reflecting on the foundations of knowledge for him.

He does this beginning with the sensory inputs that he has. Should he trust his eyesight? Well, coloured things look a different colour under different lights. You make mistakes when you see things in the distance, too. Nearby a straight stick looks bent when half in water. Should he trust his hearing? That can be wrong too. Should you trust any of your senses? Maybe you should trust the sense of touch. But there are illusions with this sense too.  But what about the fact that you could be deceived about just about anything in a dream? You could be dreaming. That’s an outside possibility most of the time, but still a possibility. He’s had these false awakenings in real life, he’s imagined he’s woken up when he hasn’t. And he thinks, Well, I can’t be sure I’m not dreaming now. How do I know I’m not dreaming now? Probably, I’m not dreaming now. But I could be dreaming. And he pushes and pushes with this and thinks—he’s a mathematician—‘even in dreams, two plus two equals four’. But what if there’s an evil demon that exists—it probably doesn’t—but what if there were and he is almost as powerful as God, and creates the illusion that two plus two equals four, when it actually equals five? And because it’s so powerful, how do I know that’s not going on now?

“For me, when I read it as an 18-year-old, I was stunned”

So he’s got this kind of progressive doubt that is actually pre-emptive. He’s not saying that you should doubt all these things. He’s pushing doubt as far as he can, then to perform a U-turn, to get beyond skepticism. He’s descended to the nadir of doubt, as it were, the lowest point he can possibly go and feels that he’s in a whirlpool of doubt. And then he finds this one thing which he thinks is impossible to doubt, which is his own existence. Because even if he doubts that, it proves that there’s a doubter. And you get this famous, “I think, therefore I am”. It’s questionable whether it’s a logical ‘therefore’. But there’s a sense that it’s impossible to doubt your own existence without certifying your own existence by the fact that you’re having a thought. And this leads him to think that he can be more certain of his own existence than he can be even of his own body, because his knowledge of the body comes from sensory information. And that’s always unreliable. But his knowledge of his own existence as a thinking thing is, he feels, the kind of groundwork or base from which he can rebuild the whole edifice of knowledge. That’s basically the first Meditation.

Then, in the subsequent fives Meditations (there are six in all), by a few devious moves, he gets back to normality. These devious moves involve proving the existence of God and then a benevolent God who wouldn’t deceive him. So he ends up thinking that whatever he perceives clearly and distinctly is true, and from that point gradually rebuilds more or less everything he had believed before.

Historically, the important thing is that pushing of skepticism as far as it can go. He gives us the ‘cogito’ argument and then puts forward a dualism between mind and body, because he’s certain of his own existence, whereas he can still doubt his own body. That’s one stage away from his own final position, which is that the soul is separable from the body, which was an orthodox Catholic belief. That’s an offshoot of his theory. Descartes is famous for this dualism, where he believed that the mind and body interact. They’re not the same thing. And so you have this Cartesian dualism of mind and body interacting, the mind stuff and the body stuff, the soul as it were, and the physical material body, which, in many people’s view, set philosophy off on a wrong path for hundreds of years. It’s what the Oxford philosopher Gilbert Ryle described as the myth of the ‘ghost in the machine’.

But it’s an incredibly important book, not just historically, but also because it was very accessibly written and gives you the excitement of thinking things through, and makes a good starting place for studying philosophy. It’s argued, it’s not just asserted, and some of the sceptical arguments are very plausible. And if you have not come across it before, it can pull the rug from underneath your assumptions one by one. For me, when I read it as an 18-year-old, I was stunned, because I thought, ‘Could I be dreaming?’ Most of us haven’t progressively moved through those stages of doubt in that way.

I read the Meditations when I was studying 17th century history as an undergraduate. I didn’t know quite what to make of it.

He gives a better description of the Cartesian method of doubt in a different work, where he talks about a barrel of apples. If you want a good barrel with no rotten apples, you have to take them out one by one, and examine them and not put any back in again until you’re absolutely sure it’s not rotten. You don’t want to take the risk of putting a rotten one in. That’s what he thinks he’s doing. He doesn’t want to put any rotten belief back into the barrel. And he’ll probably sling some good ones out as a result. But he wants to be absolutely certain about some things, he doesn’t want to just take a chance.

Life is lived for us as a matter of probabilities most of the time. We don’t worry about really long odds of things possibly being misleading. But, for Descartes, this was about trying to understand the absolute basis of our human knowledge and its limitations and whether nothing could be certain, whether even the idea that nothing is certain might be uncertain. That’s the extreme Pyrrhonian skepticism after Pyrrho, the Greek philosopher, and Descartes doesn’t end up there. But he starts off by using the same kinds of arguments. It seems to me that it’s a plausible exercise, you’re trying to understand how we acquire knowledge and beliefs, and how reliable those methods are. He pushes those things to the limit, you’re testing these things to destruction. These are thought experiments, he’s not prescribing this as a way of life. It’s a once in a lifetime device.

I didn’t understand how Descartes can conclude that there is a God, for example.

He uses the ontological argument, which is basically the idea that, by definition, God must exist. It’s like the three angles of triangles having to add up to 180 degrees by definition. From the definition of God, it must follow that there is a God because God is that entity than which nothing greater can be conceived. And there must be such an entity. To many people, that seems like a sophistical argument and totally implausible.

He also uses a version of the argument from design, which is usually known as the trademark argument: if you introspect, you’ll find you have an idea of God.  Everybody’s got an idea of God. Well, it must have come from somewhere, God left that stamp in your mind to find there. Where did that idea of God come from? It’s this little hint from the maker. I’m not convinced, but some people are.

Let’s move on to David Hume’s Enquiry and why that’s made your list of key philosophical texts.

David Hume was a really remarkable thinker and writer of the 18th century. He was an atheist, or at least a very skeptical agnostic in a religious age, which made it difficult for him to find a job as a philosopher. He was an independent writer for most of his life, and a very successful one.

As a young man, in his early 20s, he published a brilliant book known as A Treatise of Human Nature, but it was quite densely written and he famously described it as falling “dead-born from the press”. It wasn’t taken up, it wasn’t discussed. He actually wrote a review of it himself, to summarize it, hoping that would help. So, amazingly—something that you wouldn’t catch many people doing today—he rewrote the book in a more popular way, expanding it in some ways, omitting other bits, because he felt that part of the problem was the style of his communication. He’s a brilliant writer, very witty, sometimes ironic, so he rewrote the Treatise as the Enquiry Concerning Human Understanding. This was picked up and became very popular as a book. He also wrote many essays specifically for a popular audience and also a long history of England that was also very popular.

“Like John Locke, he thinks that the mind is a blank slate, filled by experience”

In the Enquiry he puts forward his particular empirical account of the mind. There’s a whole section on morality and so on, but the key bit for me is where he’s talking about how, following on from John Locke and the tradition of seeing the mind as a blank slate, we get ideas from what he calls ‘sense impressions’. If you think of an impression as like a footprint left in the sand, the senses get impressed, somewhat passively, by information that comes in from outside. And the impression that’s left in the mind, when we think about it away from what we’re seeing, is called an idea.

The whole opening part of the book is about where we get our ideas from, and is it possible to have an idea without a corresponding impression? Can you think about things that you’ve never actually experienced? And he suggests not. You can combine ideas, but everything that is within the mind has come from some prior impression. That’s extremely controversial, because people think of genetics, of patterns of thought that must be there in the mind. Kant reacted very strongly to this, he described Hume as ‘waking him from his dogmatic slumbers.’ And Kant’s Critique of Pure Reason is an attempt to show that certain sorts of patterns must be imposed on all our thought,  in order for us to have any thought at all. But Hume’s empiricism is very interesting and very, very important.

Why is Hume called an empiricist?

He’s called an empiricist because, like John Locke, he thinks that the mind is a blank slate, filled by experience. Empirical knowledge is a knowledge acquired through the senses as opposed to by some kind of a priori reasoning. I know that apples are red and crisp because I’ve seen red apples and bitten into some of them. These are empirical observations that I’ve made from which I generalize.

Many people think that two plus two equals four is not an empirical observation, it’s not because I’ve added two apples and two oranges and got four fruit over and over again that this is true—it’s because of some kind of abstract relationship between symbols that I can recognize as holding. Hume would agree and see this as a relation between ideas. Somebody might say we need to get the empirical evidence for those symbols – John Stuart Mill, a later empiricist philosopher, bit the bullet and claimed that mathematics too was indeed based on empirical generalisations.

Also within this book—which is three books joined together—there are some controversial and fascinating essays on religion, most notably one on what we call the ‘argument from design’. This is the argument that there is an analogy between natural objects, like the human eye, or the human heart, and designed objects, like the workings of a clock or a carriage or a building. If you look at the human eye, how could it not have been designed? Surely something incredibly powerful and benevolent must have created it?

Hume takes that apart as an argument from analogy and looks at its weaknesses. He did this more thoroughly in a brilliant posthumous book Dialogues Concerning Natural Religion, but his main criticisms of the argument from design are all contained within a chapter of his Enquiry. He suggests that even if you acknowledge there is a strong analogy between natural objects and designed ones, it doesn’t follow that there is one personal God that designed them, or who carries on existing and interacting with the world. They could just as easily have been made by a bunch of lesser gods working as a team or a God that subsequently died. He toys with all kinds of ideas, not because he believes they’re true, necessarily, but because he says that from the evidence, they’re equally probable. He even entertains an idea that is quite close to evolution as a possibility. It’s a very clever unraveling of a certain style of argument by analogy.

“He doesn’t get obsessed with his skepticism”

There’s also a brilliant essay on miracles, and whether you ought to believe the testimony of somebody who claims to have witnessed one. It turns on the idea that a miracle is a transgression of a law of nature. You’ve got huge amounts of evidence that if somebody says that somebody rose from the dead and walked about that the witness was mistaken, that there’s been misreporting. He gives some psychological accounts of why that might be so. His line is, ‘always believe the lesser miracle’. It’s a lesser miracle that someone was confused or conned than that somebody did actually arise from the dead. His conclusion is you shouldn’t believe eyewitness testimony that a statue has wept blood, or whatever the miracle might be. This was very controversial in his time and has been much discussed ever since.

Those are just examples of the sort of ideas he has. Hume has a wonderful personality that comes through his writing. It’s a playful personality. You have to work to get through some passages. The books is quite difficult in parts because of the 18th century prose, but it’s worth persevering with. It’s also very easy to find commentaries on Hume to help you through that, including an amazing website originally made by Jonathan Bennett called Early Modern Philosophy, which includes complete paraphrases of huge number of philosophical works in contemporary language, including Hume’s.

Hume excites a lot of devotion—even the American economist Paul Krugman recommended him as one of his inspirations. Is that because of the personality that you’re alluding to, that comes through in this book? Or is it because of Hume’s atheism or his empiricism?

It’s different for different people. What you can’t miss is just how intelligent he is and creative in the way he presents counterarguments and examples. He loves creating imaginary situations which allow you to understand what’s at stake and why a particular argument has gone too far in its conclusion. He’s got a very fertile mind. And he’s quite genial. There are jokes in it, which is quite unusual for philosophy. He’s somebody who’s very skeptical, but what’s attractive about him is he’s not saying, ‘you can’t really believe anything.’ Crudely, what he believes is that there’s a point where you can’t push reasoning any further and we fall back on our human nature. Rather than worry too much about it, he goes off for a walk or plays backgammon. He doesn’t get obsessed with his skepticism. He’s a mitigated skeptic, as he puts it, rather than someone who says, ‘I can’t be sure I can take a step forward because I might fall into the abyss.’ He pushes arguments as far as they’ll go, but when he can’t resolve something, he’s not tearing his hair out. In answer to your question, a very attractive person comes through. His contemporaries mostly liked him, except those who hated him for his anti-religion, as they saw it.

People don’t read him because they believe empiricism is true because very few are going to be taken in by his system. They read him because he’s a fascinating, intelligent thinker, trying to get to grips with things and has some brilliant arguments within that, some of which do hold still, particularly in the area of religion.

What was his point about the sun coming up every day?

This is the famous argument about the problem of induction. How do we know the future will be like the past? Just because the sun has come up every morning so far doesn’t mean it’ll come up tomorrow. Arguing from patterns of past events aren’t like deduction: we can’t be sure those patterns will hold in the future. Arguments from induction involve accumulating a large number of cases in support of continuity. Deduction, on the other hand, is where you say something like, ‘All men are mortal, Socrates is a man. Therefore, Socrates is mortal.’ If the premises are true, the conclusion must be true. It’s 100% true if the premises are 100%, true. A deductive argument is a truth-preserving machine.

Induction is more problematic. How can we rely on induction—as we do. This is what science relies on, this is what we do in our daily lives. We assume patterns of similarity carrying on in the way that we’ve discerned in the past? How can we rely on such an unreliable way of reasoning? Bertrand Russell’s example is about a turkey who wakes up every day until Christmas Eve, when it then gets its neck wrung. The turkey had this justified belief, using inductive arguments, that the future would be like the past, but it absolutely wasn’t. That fateful day it wasn’t fed by the farmer, instead it was taken out and killed. How do we know we’re not in that same position in relation to the sun rising and any number of inductive conclusions that we draw? I step out of my office, I expect to be in my garden, but how do I know I’m not going to be in London? Just because I haven’t been in the past it doesn’t follow that I won’t be in the future.

Hume tries to look at that, he looks at questions about cause and effect as well, and dissects them. What is it for one thing to cause another? Is it some kind of mysterious power that’s transferred from one thing to another? Or is it just finding the two things together in a certain sort of pattern? He analyzes that very systematically too. These are very deep, philosophical questions that he brought into sharp focus in the Enquiry, but originally in the Treatise.

And does he resolve the issue: can we be confident that the sun’s going to come up tomorrow or what we mean by cause and effect?

As I said, in almost everything like this, where he gets to a paradoxical situation, he says we have to rely on our own human nature in the end, the patterns of understanding the world we’re born with. This is where he’s a skeptic, philosophically. You push the skeptical arguments as far as they’ll go, and you can’t guarantee that the sun will rise tomorrow by inductive reasoning. You cannot find a warrant of induction that will be entirely reliable. Many people have tried since. It’s disconcerting, but you fall back on human nature at a certain point: we just do stuff.

At that point, you just go for a walk or whatever.

That’s more or less what Hume says—that or go and play backgammon. Most of us take for granted that we can rely on induction. We take for granted we know what we’re talking about when we talk about causes of things. If a billiard ball hits another and the second one moves, we say the first one caused the second one to move. But what do we mean by that? Just that whenever the first one hits the second one, it will move? It’s kind of mysterious, what we mean by it. And Hume teases that apart and looks at it analytically. That is a fundamental question in science, identifying cause and effect and what we mean by causation.

Hume is incredibly important at opening up significant questions and putting forward arguments and thought experiments to demonstrate what he meant that have been the hugely discussed since.

Just as an aside, if anybody does catch the Hume bug, his life is absolutely fascinating. There’s a great biography of him written in the 1950s by Ernest Mossner, which I think is better than any subsequent biography of Hume, though others have come out since. He was a fascinating man, so I’d recommend that strongly. There’s also a fascination section in Michael Ignatieff ‘s book The Needs of Strangers where he describes James Boswell visiting Hume while he’s dying, and the conversations they had and the significance of Hume’s death as an atheist in a religious age. Boswell, as a Christian, doesn’t believe Hume is really going to his death without fearing it, but Hume seems quite happy with the sorts of arguments that Epicurus and Lucretius used about why you shouldn’t fear dying, even though they didn’t believe in any kind of afterlife, or any separable soul. Hume didn’t seem to either. It’s a lovely summary of a real deathbed scene with the characters of Boswell and Hume in stark contrast.

Okay, let’s move on to On Liberty by John Stuart Mill. It’s our most recommended book on Five Books. Why is it significant?

On Liberty was published in 1859, the same year as the Origin of Species but wasn’t entirely eclipsed by it. It’s a slim book. There was actually a version of it published in Mill’s lifetime that could fit into a worker’s pocket. It’s a book written for a general audience, though today the language can seem convoluted because Mill wrote in very long sentences with quite complicated syntax at times.

What this book does is hammer home one truth. Mill described it as a “philosophic textbook of a single truth”. According to him it was hugely influenced by his discussions with his wife, Harriet Taylor, though she didn’t physically write it, and it’s his name on the cover. As the title suggests, it’s focused on liberty, on freedom. It puts forward what’s come to be known as ‘the harm principle’ which is that the only justification for the state or other people interfering with the lives of adults is if they risk harming others with their actions. (Adults doesn’t include children or people who’ve got psychiatric problems, or peoples in their ‘nonage’, as he rather worryingly puts it in the book—that is a kind of imperialist denigration of some more ‘primitive’ people as opposed to the Western, ‘civilized’ human beings he’s writing for). Then the whole book is an of unfolding of that principle in different areas.

“The people with whom you disagree do you a huge favor by making you clarify what you think”

Put it another way, John Stuart Mill is very vigorously against paternalism (or maternalism), of acting as a parent would to a child, of protecting someone for their own sake—whether that’s by creating rules, or by what he called the ‘tyranny of the majority’, the great forces of social power that shape people’s lives through pressures to conform. He felt that individuals should be allowed to decide for themselves and make their own mistakes. You could argue with people, you could criticize them for what they’ve done, but you should never coerce people who are adults, because that invades their autonomy in significant ways, and will be bad for society in the long run.

Mill was famous for his utilitarianism, the idea that you should aim to maximize happiness for the greatest number of people. His was a more sophisticated version of Jeremy Bentham’s utilitarianism. Bentham, one of his mentors, cashed out everything in terms of pain and pleasure. For John Stuart Mill, in contrast, there were higher and lower pleasures, and these were not commensurable, there’s no common currency in which you could measure them both. He thought of human beings as progressive in the sense that we could become more fulfilled in all kinds of ways. And he wanted a society which gave us space to grow and to do that. He felt—and this is part of his empiricism and he’s very much in the empiricist tradition—that we learn by our mistakes. You cannot know, in advance, how things are going to turn out, you need to experiment. And we are all what he called ‘experiments of living.’ Now, each of us probably knows better than other people what will make us happy. But even if we get it wrong, it’s better that we’re allowed to make our own mistakes, and experiment for ourselves,  than have somebody else’s view of what we should be forced upon us.

Where was he coming from politically? He’s sounds libertarian.

He was actually an MP for a while at Westminster, a member of the Liberal Party. Libertarian philosophy can find a lot in John Stuart Mill. It’s written very much from an individualistic point of view, with the claim that by allowing individuals to flourish, we will produce a better society. So, for instance, one of his arguments is that what makes societies progress, often—and this is controversial—is geniuses. We need geniuses to push the boundaries, to make us think differently, to invent new things, to find radical new ways of doing things. According to Mill, just about every genius is perceived as weird and an outsider figure because they don’t conform with the expectations of other people. The conditions which allow geniuses to flourish is to give them space to do what they want to do, by not making them conform with other people, or coercing them to be like other people. So that if you want to have geniuses, you need to give such people personal space to do stuff that other people might disapprove of. As long as they don’t harm other people in the process, they should be free to do that, even if it offends other people that they’re doing and thinking these things. So that’s one way in which society is improved according to Mill.

The other general way is that he believes individuals relish making their own mistakes. Choosing for themselves is almost an existential position.

He also defends extensive freedom of speech. Chapter two of On Liberty is the most important defence of a liberal position on freedom of expression, where he argues that people should be free to express themselves up to the point where they incite violence. That point shouldn’t be measured by the words that they utter, but by the context in which they utter them, and the likelihood of its giving rise to violence. So, for instance, he says it’s fine to write ‘corn dealers are starvers of the poor’ in a newspaper editorial, but if you put that on a plaque and wave it in front of an angry mob outside a corn dealer’s house, that constitutes incitement to violence. And that is the point at which you can curb an individual’s freedom of expression.

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So he makes a distinction—still very important, I feel—between offending people, which he thinks is an almost inevitable consequence of saying things in public, and actually harming people. This has been controversial too, of course. He didn’t have a rich concept of psychological violence, what could be done to someone with words alone through a certain kind of hate speech. That’s something which you might want to modify.

But, generally, the idea that society benefits from a free market of ideas is one which a lot of people still respect and believe. He puts it in terms of the value of conversation, of public discussion of key ideas. The people with whom you disagree do you a huge favor by making you clarify what you think and encourage you to hold your beliefs in a non-dogmatic way. He’s very much into the idea that until you’ve had your ideas tested by somebody who believes they’re false, you just hold them as a mere dogmatic belief, not a living belief that has survived criticism. In a sense, that chapter is a summary of what many of us think is central to philosophy in general, the idea that you test ideas to destruction, and one of the best ways of doing that is by having conversations with people with whom you disagree. So in fact, the single voice that stands in opposition to the mob, as it were, is the one that he values most highly, because it’s the one that makes people think. It’s easy to conform and even if the person is wrong, there might be a little bit of truth in what they say that wouldn’t otherwise come out, so you don’t want to silence them in advance and stop them saying things.

He’s much closer, I would say, to the way free expression is treated in American law than in British law, because we do have restrictions on the things that people can say in the UK. There are good arguments for having laws against anti-racist, anti-homophobic and anti-transphobic speech, perhaps, but he was much more laissez-faire in this respect than many European countries’ laws are. I think it highly unlikely that he would approve of censorship of Holocaust denial, for instance, even though he’d think it would be outrageous that people are denying its existence. The point is that when people do that, it’s an opportunity to refute them, and to show point by point where historically they’ve gone wrong. They shouldn’t be silenced in advance.

Where is all this coming from? It’s not out of the blue, presumably?

It didn’t come out of the blue. There are lots of precedents in Milton, for instance. Many of his arguments were prefigured in a little book that Milton wrote called Areopagitica, which was a tract in reaction to pre-censorship of books, banning books before they’re published, killing books, as Milton put it.

Mill came out of quite an anti-religious group of free thinkers. If you look at them, many of the arguments about freedom of expression are reactions to certain sorts of censorship and arguments to conform that came from religious sources.

He’s part of a group of intellectuals who felt that freedom was incredibly important and was essential to what a human being is. Within the utilitarian tradition, there was a strong thread of allowing people to flourish in whatever way they wanted to when they weren’t harming other people, because that would add to the general happiness in the world. Interestingly, for instance, I mentioned his mentor, that eccentric figure, Jeremy Bentham. Although it wasn’t published in his lifetime in the 18th century, Bentham wrote about the irrationality of prosecuting practising homosexuals, because that would likely diminished the amount of pleasure in the world, and they weren’t harming other people by their consensual actions. That was very radical when homosexuals were still being hanged. He certainly would have been prosecuted if he’d published it in his lifetime.

So Mill didn’t come out of nowhere. No one comes out of nowhere.

Finally, we’re at Wittgenstein’s Philosophical Investigations. This is a book I know nothing about.

This book was published posthumously, from the notes that were left to Elizabeth Anscombe, his friend. He’d been putting this book together for ages and at his death it hadn’t quite come together. She eventually edited, published and translated it. He wrote it originally in German, though Wittgenstein did speak English. He was from Vienna, a great Austrian intellectual from a hugely wealthy industrial and highly musical family. It was an unusual family. His brother was a concert pianist who lost his arm in the First World War and carried on his career very successfully, commissioning concertos for one hand from Ravel and other people. His other three brothers committed suicide.

Wittgenstein came to Cambridge just before the First World War after initially starting off as an aeronautical engineer studying in Manchester. He switched to philosophy and became interested in mathematics and the foundations of logic. He persuaded Bertrand Russell to take him on as a student and then, having had these very intense discussions with Russell and other Cambridge philosophers, he fought on the other side in the First World War, and wrote his first book, the Tractatus Logico-Philosophicus, while in a prisoner of war camp. He thought he’d solved all the problems in philosophy and then went off and worked as a gardener and subsequently as a schoolteacher for a while.

Then, eventually, he realized that maybe he hadn’t solved all the problems in philosophy and came back and became a professor of philosophy in Cambridge. He was extremely eccentric and lived in a room with no books and just some deck chairs and an army bed. It was very plain, very bare. He didn’t give normal lectures; he would just wait for somebody to come up with a problem or an issue and then he would discuss it. Then, halfway through the discussion, he would tear his hair out and say, ‘No, no, I’m a fool. I’ve said that wrong’ and start off again in another direction.

Gradually his ideas coalesced, and his students wrote them down in notebooks and these got circulated. He had very radical ideas about the nature of the mind and its relation to language and how we think and what philosophy is. These ideas then reach their most popular version in the Philosophical Investigations, this posthumously published book. It’s a series of fragments, really, a series of numbered propositions, not completely coherent, jumping from topic to topic, almost aphoristic some of them.

Ideas that come out of it include an attack on what’s come to be known as the Cartesian picture of our relationship to reality, that we have an inner picture of what the world is like and that we describe it to ourselves in a private language. Wittgenstein was in a more behaviorist tradition in the philosophy of mind, arguing that language is a public medium, that we don’t have private meanings in our heads, that we learn things and communicate in certain sorts of ways that are shaped by our ‘forms of life’—the complex social webs in which we live. Our minds are much more legible than philosophers had previously thought. We have to recognize that we’re in a community of social beings communicating with each other and there aren’t these private meanings in our heads.

Another idea that is very important in the Philosophical Investigations is the idea that philosophy arises, as he puts it, ‘when language goes on holiday’. That’s a typical Wittgensteinian phrase, and what he means by it is that most traditional philosophical problems arise because people are using words that have a perfectly reasonable use in one context but they’re using those words in another context, and then wondering why they get into paradoxes. And so, by analyzing language and how we use it, we might be able to dissolve a lot of philosophical problems. He thought that by his method of revealing to people where their confusions lay he would, as he put it, let the fly out of the fly bottle. A fly bottle is a device for trapping flies with a small neck. And these flies are buzzing around in there. And what the philosopher does, if he’s a good philosopher like Wittgenstein, is let the fly out, and then there’s no more buzzing.

It’s a kind of philosophy as therapy. Once you’ve done it, you needn’t do it again. He spent some of his life telling people who were studying philosophy to go off and work in factories rather than have careers as philosophers because he thought a lot of philosophy was simply a waste of time. Once you’ve solved these problems, you can just get on with something else.

He was a very charismatic figure. The thing about the Philosophical Investigations is that it’s very rich as a stimulus to other people’s thought, there are a huge number of interpretations of exactly what he meant.It’s not some kind of wild poetry as some people take it to be. There are patterns within what he’s saying.

“He thought he’d solved all the problems in philosophy”

Another important idea of his is about how we suddenly see things differently. He’s got the example of the duck-rabbit, the famous illusion, where you have this line drawing that you can see either as a duck or as a rabbit. But you can’t see both at once. And he talks about ‘the dawning of an aspect’, of aspect seeing. The retinal image doesn’t change when you see a duck and then you see a rabbit: it’s exactly the same pattern reflected within your eyes, but it’s a kind of gestalt shift where you suddenly see it as one or the other. This is how human beings engage with the world when we see things under descriptions. We can flip between different ways of seeing things without the things themselves changing. He then applies that in various ways.

Another important thought of his is about how philosophers generalize. They’re looking for abstract generalizations about the world, they’re not just talking about one rock, they’re talking about matter; they’re not talking about one person’s thoughts, they’re talking about mind, or consciousness. Wittgenstein has an anti-essentialist thread running through the Philosophical Investigations. Take his example of a game. What is a game? Do all games have something in common? Don’t just assume they do, he says, look and see. Then he runs through all the different sorts of games—throwing a ball against the wall, playing cricket, athletics. All kinds of things are called games. We tend to assume as Socrates did (according to Plato), that if they’re all called ‘game’, there must be some essence of the thing that makes them games. Maybe they have a winner and loser. Well, what about solitaire? Maybe they’re all activities, but you can play chess in your head (that’s probably not a very good example for him, because he wouldn’t say ‘in your head’). But his thought is that there are these things which he calls ‘family resemblance’ terms. ‘Game’ is a family resemblance term. You can see the resemblance between people in a genetically related family, but they might not all share one common feature. They don’t all have the same-colored eyes, they don’t have same shape cheeks, but there is a pattern of overlapping similarities between them. Analogously, games don’t all share some key feature.

He thought that we assume with language, when we use one word in different contexts, there is some essence that carries across all those different things. But he says there’s a cluster of different things there, patterns of overlapping resemblance. Using another metaphor, if you have a piece of rope, lots of fibers are overlapping, but there is probably no single strand that runs the whole length of the rope, there is no essence of the thing that makes it what it is. And, once we recognize that, a lot of problems in philosophy will dissolve. When you start looking for the one thing that all freedom has in common, or one thing that all consciousness has in common, that kind of essentialism, it can be a flawed assumption in your reasoning.

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There are many different aspects of Wittgenstein, a huge number of things that are brought up by this very original thinker. He’s somebody who deliberately tries to provoke you to thought, rather than doing the thinking for you. There are big gaps between what he says which you’re supposed to fill in by your own reasoning and either move along with him or disagree with him. It’s a really interesting, important book in the history of philosophy. It can be irritating too, because it’s far from obvious some of the time what he is getting at. And sometimes his style of writing can be a little too indirect. I think, though, that he would have been glad to know that people are still discussing it and arguing about what he meant nearly seventy years after it was published.

I’m interested that in the entire history of philosophy, Wittgenstein makes the cut.

He’s had a massive influence on 20th century philosophy, that’s why. I’m not entirely a fan of his. I certainly wouldn’t be a fan of his personality; he would be a horrible person to have to deal with, often a jerk—more worried about his own honesty to himself than hurting others around him. But he’s an incredibly important thinker because he’s introducing new ways of seeing the subject. Whether you agree with him or not, he’s had a huge influence.

And non-philosophers could understand the Philosophical Investigations?

I don’t think anybody understands all of it, in the sense of being able to say definitively what he meant by everything in it. There are numerous commentaries, and their authors disagree with each other about key points. But I think people can get something out of a lot of it. I think the way to do it is to read bits of it, be confused by it. Take on what you can, and then possibly go to some commentaries—of which there are many—and read it again and think about it again and see whether it makes sense to you. The section on what a game is might be a good place to start. I don’t think the ideas are impossibly difficult to grasp. It’s a lot easier than the theory of relativity, the things he’s dealing with, though he does it in an indirect way, often, by getting you to think about scenarios rather than telling you straight out what he thinks and it is not always obvious whether he is endorsing a view or merely entertaining it in order to refute it.

I love his quote, “whereof one cannot speak, thereof one must be silent”.

That’s the last line of his earlier book, the Tractatus. That was about the limits of what can meaningfully be said. He was kind of mystic in that book: religion, ethics, everything important about humanity, you might say, is beyond the pale and you can’t talk meaningfully about it.

But then he came back and wrote The Philosophical Investigations.

There’s an early and a late Wittgenstein. The Tractatus is the early, extremely difficult book, but with some lucid aphorisms within it. The Philosophical Investigations is more approachable, more psychological in places. It also has its difficulties, but you can get more out of dipping into it.

Editor’s note: If you enjoyed this interview, Nigel Warburton’s book, A Little History of Philosophy, has chapters on all these philosophers, plus many more—around 40 in a total. For anyone who’s interested in learning more about them and understanding a bit of the context, it’s a brilliant introduction.

Interview by Sophie Roell, Editor

July 2, 2021

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Nigel Warburton

Nigel Warburton

Nigel Warburton is a freelance philosopher, writer and host of the podcast Philosophy Bites. Featuring short interviews with the world's best philosophers on bite-size topics, the podcast has been downloaded more than 40 million times. He is also our philosophy editor here at Five Books, where he has been interviewing other philosophers about the best books on a range of philosophy topics since 2013 (you can read all the interviews he's done here: not all are about philosophy). In addition, he's recommended books for us on the best introductions to philosophy, the best critical thinking books, as well as some of the key texts to read in the Western canon. His annual recommendations of the best philosophy books of the year are among our most popular interviews on Five Books. As an author, he is best known for his introductory philosophy books, listed below:

Nigel Warburton

Nigel Warburton

Nigel Warburton is a freelance philosopher, writer and host of the podcast Philosophy Bites. Featuring short interviews with the world's best philosophers on bite-size topics, the podcast has been downloaded more than 40 million times. He is also our philosophy editor here at Five Books, where he has been interviewing other philosophers about the best books on a range of philosophy topics since 2013 (you can read all the interviews he's done here: not all are about philosophy). In addition, he's recommended books for us on the best introductions to philosophy, the best critical thinking books, as well as some of the key texts to read in the Western canon. His annual recommendations of the best philosophy books of the year are among our most popular interviews on Five Books. As an author, he is best known for his introductory philosophy books, listed below: