Or the only truly tested philosophy is that of a dead philosopher. When the philosopher dies, the philosophy is put to the test. Does is still seem valid? Or does it fade into irrelevance in the face of eternity? From the Sydney Writers' Festival, a conversation with Simon Critchley, author of The Book of Dead Philosophers.

Alan Saunders: Hello, and welcome to The Philosopher's Zone. I'm Alan Saunders.

Philosophers who seek to learn how life is to be lived, must also ask how the project of life is shaped by the knowledge of its eventual termination. And when the philosopher is dying, the philosophy is put to the test. Does it comfort you? Does it strengthen you? Does it still seem valid? Or does it fade into irrelevance in the face of eternity?

These are some of the questions asked by Simon Critchley, Professor of Philosophy at the New School for Social Research in New York, in his recent Book of Dead Philosophers, which looks at some famous philosophical departures, from Socrates in ancient Athens to David Hume in 18th century Edinburgh.

And here he is in conversation with me at this year's Sydney Writers' Festival. And we're beginning by looking at how death was faced by a very sober, unreligious, scientific-minded thinker indeed, the English logical positivist, A.J. Ayer, who died in 1989.

Simon Critchley: He choked on a piece of salmon, but he revived; he was technically dead for two or three minutes and when he revived he had a near-death experience. And he reported that he was in this vast space, and everything was coloured red, and he could see himself, and he was aware that something was wrong with space and time, there were ministers of space and ministers of time. The ministers of space were present but the ministers of time were absent. And he remembered through Einsteinian physics, that time-space was a continuum. And he was trying to indicate this by shaking his watch, he was walking around with his watch. Then he revived, and lived for another year or so.

And there's a lovely story that his wife tells, that she said to Jonathan Miller, who remarked Well Freddie's in spectacularly good form these days. And she said, Yes, he's so much nicer since he died. And it caused Ayer to doubt the question of the afterlife, and he published an article in The Sunday Telegraph or something to that effect. It's an interesting story.

Alan Saunders: Perhaps we should get to some more serious philosophical deaths and - I mean all deaths are serious, but the sort of canonical philosophical death is Socrates, and his is the death from which we are supposed to learn how to die, aren't we.

Simon Critchley: Yes. The philosopher for Socrates in the Phaedo is the person who professes death, the person who is already half-dead, Socrates says, already half-dead. So to be a philosopher is to be half-dead. It's the meaning of study, one of the meanings of the word 'askisis' is 'study', you know there's a certain sense in which to read books is to die a certain way, you're not attending to the world, you're a contemplative. And the Socratic death is one where - I mean you've got different ways of interpreting this, but he says in the Apology that 'I'm going to die and there will either be an afterlife, which would be rather nice because then I would meet Homer, Hesiad and the rest of the Greek heroes and my old friends; or there's nothing, just a dreamless sleep. And one way or the other we don't know.' And I make a great deal of emphasising this fact that Socrates and the Socratic approach is one of not knowing. Philosophy is a love of wisdom, but not a knowledge, and what philosophy requires is a certain suspension of claims to knowledge in the name of the cultivation of his practice that Socrates calls love of wisdom, philosophy. Which one engages with another person in conversation.

And so Socrates is the model of the philosophical death and in many ways there are antecedents, but there are an awful lot of successors and the story that I try and tell, it's comical as well, but it's a very serious failing, many of the high points in the history of philosophy turn on this question of how the philosopher dies. Famously, Hume. Hume's death is extraordinarily important because this is the death of the atheist. Can Hume the atheist die without wanting to convert to Christianity or believe in the afterlife? And Boswell, Johnson's biographer, visited Hume twice and Hume admitted him to talk about this question and Hume persisted until the end in his belief that there was no afterlife. And so his is the idea as with the philosophical death, as accepting one's mortality without running off into the afterlife, and Boswell says to him, 'Well don't you at least accept the possibility of an afterlife?' and he says, 'It's possible that if I throw a piece of coal on the fire, that it will not burn.'

Alan Saunders: It's interesting that if you read Boswell's journals after these little interviews with Hume, he went out into the streets and got a prostitute. He wanted to have sex, so it was clearly sort of Eros asserting itself against such a display of vanitas.

Simon Critchley: Right, yes. Which I recommend to all of you here. I'm sure Sydney has many such -

Alan Saunders: But the question of -

Simon Critchley: King's Cross for instance.

Alan Saunders: Yes, well absolutely yes. The question of the afterlife versus annihilation is interesting here. I mean Bertrand Russell, great analytical philosopher, said that he thought our respect, our admiration for the way in which Socrates went to his death, has to be tempered by the fact that he believed in an afterlife, so it wasn't as brave as all that. Now of course it's not clear, is it, to what extent that is Socrates and to what extent it's his pupil, Plato for whom we are largely reliant on our accounts of Socrates.

Simon Critchley: Yes, we don't know. There are four Dialogues devoted to the trial and death of Socrates. The Phaedo, the last of them, is where he makes the arguments for the immortality of the soul. Did Socrates believe in immortality of the soul ? We don't know. They're exceptionally bad arguments, and given that Socrates wasn't stupid, there might be a reason why the arguments are poor. My interpretation of Socrates' death is that he wants to die selfishly, in his way at the time he chooses, and he throws out these arguments about the immortality of the soul in order to make his followers feel better, knowing that they're not good arguments.

So in a sense, this raises the question, Well there's two things, I mean there's another great philosophy in antiquity central to this question, Epicurus, about whom we know very, very little, there are just four letters, the Doctrines of Epicurus, are related in Lucretius' On the nature of the universe. Fantastic text. Epicurus has this statement, 'You should not fear death, when death is I am not, when I am, death is not, therefore why worry?' So the philosopher is the person that can achieve a calm, this is a key, ataraxia, a calm in the face of death. Philosophy is a process, is a four-part cure, it's the tetrapharmakos, which I can't remember: do not fear God, what is good is easy to get, and there are two others.

The point is that the philosopher is the person who can face the thought of their annihilation without consolation and face that with calm, and that's an idea that sort of trickles down the last 3,000 years in a really interesting way. Talking of Hume, Hume would be a very good example of that. I think Russell, too. I think Russell's views on the afterlife are very consistent with that.

Alan Saunders: And that's in keeping with what we are told were Socrates' last words which were 'Critto, we owe a cockerel to Esculapeous', that's to say a sacrifice of a cockerel to the God of Healing.

Simon Critchley: Yes, death is curative, it's a curative slumber. And the point is that it's not to be morbid, it's just that we're live in cultures where death is the last great taboo. And philosophy for the last 2-1/2-thousand years has been concerned with that issue, overwhelmingly concerned with that issue, or learning how to die. So we would do well to attend to that thought, death as a curative slumber

Alan Saunders: And in support of your view that Socrates was dying when he wanted to, I mean he was condemned to death for corrupting the youth of Athens and for denying the Gods, the local Gods, and he was made to take hemlock so he was sort of the agent of his own execution, but he could have copped a plea bargain if he'd really wanted to, couldn't he?

Simon Critchley: Or chosen exile.

Alan Saunders: Or chosen exile, yes, but he decided not to.

Simon Critchley: Yes, he decided to die in his way at a time of his choosing. That's a euthanasia in that sense, that's dying well. That would be the message of a whole strand of the history of philosophy.

Alan Saunders: If we take the Epicurean or the Lucretian argument, what it amounts to roughly is this: death is in the nature of things, annihilation; annihilation could not be experienced; it's irrational to fear that which one would not experience, therefore it's irrational to fear death. And I suspect the world is divided into people who are convinced by that argument and those of us who find it just somehow fishy even though we can't quite put our finger on it. Thomas Nagel, the American philosopher's done a very good paper on that subject, and Phillip Larkin's poem, Aubade, tries to capture why you might feel afraid of annihilation, even though you know it's not something you're going to experience. I suspect you accept the Epicurean argument, but do you have any sympathy with the - ?

Simon Critchley: I'm sort of Yes and No. I think it's the Epicurean tradition is one that I want to defend and one of the Epicurus is the hero of the broken people that I see, as returning to that tradition, like Spinoza, like Hume, are sort of heroes of the book. Montaigne. But there is something absolutely selfish, solitary, about this idea of the philosophical death.

One of the arguments that Lucretius makes is that Well there was a time before you were born, are you worried about that? No. There'll be a time after you're dead, why worry about that? This is called the equivalent cycle, if you're not worried about the time before you were born, you shouldn't worry about the time after you're dead. But the thing is, it's here and screw the time we were born, we're looking at life that way, we're looking at life as it were, down the tunnel of our finitude, so it feels different, and that's why we want longevity. But I think the more serious problem with that view is its solitariness, and this is something that I try and - a big theme in the book is the deaths of others, that the philosophical death is a solitary death, usually the death of a man surrounded by his disciples, Epicurus, Socrates, women are asked to leave. Xanthippe, Socrates' wife, is asked to leave, so there's that question. But also that what most affects us in death is the deaths of others. And death enters the world for us through the deaths of those that we love, and we mourn, and it's that experience of mourning that leaves the self incomplete in an essential way I think.

Alan Saunders: The philosopher that we haven't mentioned yet is Seneca, the Roman Stoic philosopher, and of course Stoicism was a very good philosophy if you were going to be philosophical tutor to the Emperor Nero, but there is, I mean when you talk about the way that one's death affects others, Seneca is one of the few philosophers I can think of, well to be honest he's the only philosopher I can think of who actually appears in an opera. He appears in Monteverdi's opera The Coronation of Poppea, and he's sitting with his disciples when the sentence of death arrives, and he, like Socrates, though by different means, is going to have to kill himself, and he's been telling his disciples how this world is of no value at all, but when the order comes, they all sing 'Non morir, Seneca, non morir, Seneca, non morir, Seneca, no.' 'Do not die, Seneca' and they then break off into a beautiful little sort of madrigal about the beauties of the world which he is electing, as they say, to leave. And then they return to the 'Non morir, Seneca', so they are simultaneously prematurely mourning him and also trying to persuade him not to go because life is so good. So we're immediately given a sense that he's not just leaving an abstract world, as it were, he's leaving people who don't want him to go.

Simon Critchley: Yes, sure, absolutely. Seneca is another key figure in this. I spent a lot of time in the book talking about the deaths of Christian saints, and I try and show how the death of the philosopher becomes transposed into the death of the Christian saint. St Antony is the great example that Bishop Athenazis' Life of Antony which is all about how Antony faces his death, and Antony is a Socrates figure. But the key thing about that is if you're looking for literature on grief and mourning, then the Early Christian tradition is a fantastic text. I mean Gregory of Nyssa on the death of his sister, but most particularly, Augustine. Augustine's Confession and Augustine is the philosopher of grief in that sense. He grieves over the death of his friend and the death of his mother. And the death of his mother just tears him into two. It leaves him rent, and he then feels shame for the mourning that he undergoes, but has to express it.

And so on the one hand the Epicurean Socratic Senecan idea of death as an ideal of solitary facing of death in calm, I think is enormously compelling, but it doesn't face up to this question of grief and the way grief leaves us undone, and I want to say that the self is something which is done and undone in this experience of grief, and we carry those that we grieve over in us, but as memories, as things which in a sense we cannot fully capture. There's a deep problem with grief and mourning in the philosophical tradition. So for that I go into, if you like Christianity and other spiritual traditions.

Alan Saunders: It's also a problem, isn't it, in the world generally. I'm sure that if one of us were to die here on this stage and somebody else organised our funerals -

Simon Critchley: It would be great for sales, though.

Alan Saunders: Yes. I don't know about you, I haven't organised my own funeral. But it's as like as not that your funeral, the invitation to the funeral would be 'A celebration of the life of Simon Critchley', that's the way funerals are presented to us very often these days, with or without a spiritual component involved. But that's almost to deny mourning, isn't it?

Simon Critchley: Yes. There's a terrible problem with mourning. We're not allowed to mourn, we're not allowed to grieve. This also has a political meaning, you know. The great American philosopher, Judith Butler has argued that in relationship to 9/11, George Bush, 11 days after 9/11 said the period of mourning is now over. 'Now we're going to go and kick some ass', you know. So whereas what if the United States after 9/11 had become say a culture of mourning, a culture that decided to look at itself as undone by this event. And how might an ethics and politics change if we adopted such a view? I think it would change a great deal. So mourning is a hugely important issue.

I wrote this book in Los Angeles. I was the philosopher at the Getty Museum, it was an ossified existence, ossified luxury with a hot tub and everything. And in many ways, this book is about Los Angeles as a capital city of death, in the sense in which it's premised upon a terror of annihilation and a denial of death. And there's this place that I went to with my sister called Hollywood Forever Cemetery, where you can do internet telecasts of funerals and repeat them and whatever. And it's based upon - and you can ring someone called Carrie Bible. Carrie Bible, who will give you tours of the Hollywood Forever Cemetery, and the whole thing is premised upon a denial of death or the idea of death as the first stage of growth. This idea that death is an illusion to be overcome through the right spiritual practice, and this is something that I think is endemic to certain New Age beliefs and older age beliefs as well. The idea of death is an illusion that we can extinguish with the right spiritual attitude. And I have to argue that death is a reality and philosophy is a way of facing up to that reality.

Alan Saunders: I want to end with a philosopher to whose death you devote a single, rather beautiful sentence. This is the French philosopher, Paul Ricoeur who died in 2005 at the age of (I'm just doing the maths) I think he was 92. And you write 'The great and gentle Hermenuetician died peaceful and without incident in his sleep at the age of 92.'

I spoke shortly after he died to one of his students who now teaches in Australia, and she said she'd been privileged to see him in his last illness and he'd spoken to her and the conversation was interspersed with moments when he just had to stop in order to recover his energies. And he said to her, 'I have finished with philosophy, I have done as much philosophy as I want to do', and having said that, he talked philosophy incessantly with her. There is that sense of 'My life's work is over, it's done, oh no actually, I can't go on, I'll go on', and I personally in the little things I do, I would like to die unfulfilled because I want to think that there are still things that I've got to do and death has stayed my hand. But do you think there is such a thing for a philosopher's thinking 'That is it. It's over. I done it'?

Simon Critchley: There are examples of that. I agree with you, but the striking example is Aquinas. Aquinas wrote 8-million words, died at the age of 49 and he seems to have suffered a stroke in his latter years, and he's reported to have said to his research assistant, Reginald, who was encouraging him to carry on with the writing of the Summa. He says 'To me it all seems like straw, the whole thing seems like straw. I can't go on.' So there is that moment of also giving up that's important. Another thing about Ricoeur which is also a theme of the book is that where did Ricoeur learn to do philosophy?

He learnt to do philosophy as a prisoner-of-war. I talked to him about this on a train to Stoke, Stoke-on-Trent and of course it was delayed for two hours, but a chance to really talk to him about - and he said 'These were non-Jewish French officers, Jewish French officers had to labour, like Levinas had to do that for five years, work in the forest, but Ricoeur was, they studied philosophy, he translated Husserl's ideas and he said that's where he got his philosophical education, in captivity. This is another theme that come up in the book, that the philosopher in captivity. Boetheus' Consolation of Philosophy is written after he's been condemned to death by the Emperor Theodoric. There's a wonderful text by Thomas Moore on a discourse on, what's it called? Consolation Against Tribulation, which is written after he's been condemned to death, and also think about someone like Gramsci.

So the idea of the imprisoned philosopher and in the prison, one achieving a certain freedom. The words of Montaigne, I mean 'He who has learnt how to die has unlearned how to be a slave'. Slavery in this sense is the denial of death, the condition for freedom is the acceptance of one's mortality, that's to say the acceptance of one's limitation. The theme that I try to finish the book with, which is a theological theme is the idea of creatureliness, the idea of being a creature, and in the Christian tradition in particular, to be a creature is to be separated from God but dependent upon God.

I want to have that sort of separation and dependence without the idea of God, and to hang on to the idea of limitation, namely, it's through an experience of limitation and the limitation that's given to us by the body and the years that we have, that gives us the possibility for something like freedom. And it's that that we have enormous difficulty with because we've bought certain myths, propounded by say, medical science and belief in technology and things that our children and grandchildren will live forever, and the idea that we can experience a life without limitation. But life without limitation would be awful. Think about Book 3 of Gulliver's Travels and the Struldbruggs, they're the immortals. And they're as miserable as sin because they live forever. That would be the worst form of captivity. So to be free, is to die.

Alan Saunders: Freedom in death from Simon Critchley who's book The Book of Dead Philosophers is published in this country by Melbourne University Press.

The show is produced by Kyla Slaven. I'm Alan Saunders and I'll be back next week with another Philosopher's Zone.