In The Gay Science and Thus Spake Zarathustra, and the posthumous The Will to Power, Nietzsche puts forward the idea of eternal recurrence, the endless repetition in every detail of the entire history of the universe, including our own lives, and including this present moment. ‘This life [he says] as you now live it and have lived it you will have to live once again and innumerable times again; and there will be nothing new in it, but every pain and every joy and every thought and sigh and everything unspeakably small or great in your life must return to you – even this spider and this moonlight between the trees . . .' I am not concerned here to enter the busy industry of Nietzschian exegesis and the question whether eternal recurrence was intended by him as a serious scientific theory or more likely, as I think, a metaphorical or poetic way of presenting a profound personal challenge. He does at one point offer an argument for it as scientific cosmology, based on the principle of the conservation of energy. The universe, he says, consists of a finite number of quanta of energy which, churning about randomly, must sooner or later, in infinite time, fall into the pattern which constitutes our universe, and must sooner or later repeat that pattern again and again an infinite number of times. However this does not occur in anything that he published himself but only in the collection of notes which his sister later put together and published after Nietzsche's death under the title The Will to Power. In his own books the idea comes as the most penetrating possible question about the value of each individual's life and of human life generally. Has your life thus far been such that you would want to live it again and again endlessly, exactly the same in every minutest detail? And would you want human history as a whole to be repeated endlessly, just as it has been? To say Yes is, for Nietzsche, the ultimate affirmation of life by his ideal type, the Over- or Higher- or Superman, who however does not yet exist except in his imagined Zarathustra. He sees the challenge to accept life as it is in this full sense as a burden which present day humans cannot bear. But to affirm life unreservedly in all its mixture of good and evil, happiness and pain, beauty and ugliness, pleasure and horror, triumph and tragedy, would not to be judge it good, or more good than bad, but would be to go beyond good and evil to a sheer act of self- and life-affirmation.

Now there are writers by whom one can be deeply moved and influenced whilst actually believing very little that they say, and for me Nietzsche is one such. I appreciate his extremely penetrating psychological and social insights. But his training was in philology, not philosophy, and we can best reap the rewards of reading him by overlooking the fact that both the challenging question and the Higher Man's response to it are logically null and void. For if there is eternal recurrence, everything, including our affirmation or non-affirmation of it, is happening exactly as it has happened an infinite number of times before, and we do not have the freedom this time round to vary it. We can have only what is misleadingly called compatibilist freedom, that is a subjective freedom which is compatible with being objectively determined – which is the unfree delusion of freedom. So in presenting the challenge to affirm eternal recurrence as though we could now determine our own response to it, Nietzsche is guilty of the error made by all who affirm or imply a total determinism, namely tacitly exempting themselves from their own account of how things are. That is, they assume that in affirming total determinism they are making an intellectually free judgement. But clearly, if they are right, the judgements of those who affirm and those who deny freewill are alike causally determined events, and there is no non-determined standpoint from which they can be adjudicated.

But having noted this, as in duty bound, let us forgive and forget it. Let us turn to David Hume who asks the same challenging question but, as the cool and lucid thinker that he was, without the poetic extravagance of eternal recurrence. He has one of the characters in his Dialogues, Demea, say ‘Ask yourself, ask any of your acquaintance, whether they would live over again the last ten or twenty years of their life. No! but the next twenty, they say, will be better'. For however satisfying our life as a whole may have been during the last ten or twenty years, we can all think of innumerable points at which it could have been better, so that, if we are comparing the way it has been with the way it might have been with these improvements, we would say No to the actual in comparison with the improved version. But we must eliminate this comparison in our thought experiment. I have to try to look back on my life as a whole during the last ten or twenty years and ask whether I would wish to live it again just as it has been, not changed or improved in any way, and without knowing that it had all happened before. It would be exactly as though one was living it for the first time, the alternative being not having existed at all.

Setting the question up in this way I think that Hume (though not the Demea in his dialogues), and also Nietzsche, and indeed all of us would opt to live it again. Only very few very unhappy people living in deep depression or in utterly unbearable circumstances of some kind would, I think, wish not to have existed. I suspect that even the millions in our world now living in dire poverty, anxiety and danger hope, with Demea, that the next years will be better and will thus make the past span of life worthwhile, not in itself but because it will have led on to that better future.

But on the other hand, still focussing on those millions who have lived in hope that life would in the future become better for them, or perhaps for their children, when we look back over human history we see that in a very large proportion of cases that hope was not in fact fulfilled. And so we have to ask whether we would want that entire history to be endlessly repeated in an eternal recurrence, or indeed in a single recurrence. If we think of ourselves simply as individuals, I would say Yes, as one of those who have been fortunate in the lottery of life. But should I say Yes on behalf of humanity as a totality, including those who have been desperately unlucky in that lottery? Would I want those who have lived in miserable slavery, or in constant fear and anxiety, or with debilitating and painful diseases, to have to live that life again and again without knowing, as they did not, that their situation was never in fact going to change for the better? Would I want those who have become sadistic monsters, from serial rapists and murderers to evil dictators, to live again and again? Would I want all the wars, persecutions, tortures, murders, rapes, cruelties and all the famines, droughts, floods, earthquakes and diseases to happen again and again? This is a challenge to the world religions, because each of them is in its own way a form of cosmic optimism, affirming the positive value of the totality of the process of which human history in this world is, according to them, a phase.

At this point I want to bring in Jean-Paul Sartre. He makes the very important point that the meaning or significance of a present event in our lives depends upon what it turns out to have led to in the future. For example, speaking of adolescent love, he says, ‘The adolescent is perfectly conscious of the mystic sense of his conduct, and at the same time he must entrust himself to all his future in order to determine whether he is in process of "passing through a crisis of puberty" or of engaging himself in earnest in the way of devotion'. And in general the significance of our present choices depends upon the larger pattern of our lives to which they contribute as this develops over the years. And it is true of us collectively, as societies and nations, that the meaning or significance of what we do now is determined in part by what comes out of it in the future. We can all recall career decisions, personal relationship decisions, commitments of many kinds, deliberate and accidental actions and inactions, whose significance both positive and negative has been determined retrospectively. I want to project this principle onto a much larger scale. I shall argue that, for the great religions, our present life receives its ultimate meaning from the eschatological future which they all in their different ways affirm. There are, to use visual imagery, widening circles of meaning, from the immediate meaning inherent in each present moment of experience, to that same moment as it takes its place in the larger context of a further, say, ten years of living, to the further, sometimes different, meaning that it takes on after another period of years, and so on as our life develops, to its final meaning in the light of the all-encompassing eschatological future.

For Sartre there is no such final all-encompassing circle, no state that, in his terms, has its value in-itself-for-itself. Death is an absolute end and there is no possibility of further life within whose enlarging pattern our present life could become a stage on the way to an all-justifying good. And so we are about to enter the culturally forbidden territory of speculation about death and the possibility, affirmed as more than a possibility by all the great world religions, that our present life is only a very small part of our total existence.

However thoughts of a life after death are all alike ruled out by the naturalistic assumption that nothing exists but matter. For if we think, in traditional Christian terms, of a further resurrected life there must presumably be a disembodied phase corresponding to the ‘sleep' before the general resurrection, or the purgatory of Catholic doctrine, or if we think in Buddhist terms there is the between-lives period described in the Bardo Thodol, and all of these possibilities are incompatible with physicalist naturalism. Physicalist or materialist naturalism assumes either consciousness-brain identity, according to which mental events literally are electro-chemical events in the brain, or epiphenomenalism according to which consciousness is not itself a physical object or process but a non-physical by-product temporarily generated by the functioning of the brain and having itself no executive power. Whether either of these theories – for they are theories - is sustainable is today the hottest point in the whole science/religion debate. Practicing neuroscientists themselves are generally not very interested in such theories, because it makes no practical difference to their work whether, in mapping brain activity in ever greater detail, they are mapping thought itself or the neural correlates of thought. However those of them who have discussed the question, and these are among the most eminent within the profession, have had to conclude that the nature of consciousness and its relation to neural activity remains a mystery. All I have time to do at the moment is to quote a few of them. Thus Professor Susan Greenfield of Oxford, well known for her TV advocacy of identity, admits that ‘I cannot at this stage describe exactly how a large number of neurons has the emergent property of consciousness'. Professor Roger Penrose, also of Oxford, who advocates an emergent property theory, adds that ‘conscious actions and conscious perceptions – and, in particular, the conscious phenomenon of understanding – will find no proper explanation within the present-day picture of the material universe, but require our going outside this conventional framework to a new physical picture . . whose mathematical structure is very largely unknown'. Professor Steven Rose, Director of the Brain and Behaviour Research Group at the Open University concludes that ‘the issue of consciousness lies beyond mere neuroscience, or even psychology and philosophy'. Dr Wolf Singer, Director of the Max Plank Institute for Brain Research in Frankfurt, believes that self-awareness and the subjective connotations of qualia ‘transcend the reach of conventional neurobiological approaches'. Professor Antonio Damasio, Head of the Department of Neurology at the University of Iowa College of Medicine, says, ‘If elucidating the mind is the last frontier of the life sciences, consciousness often seems the last mystery in the elucidation of the mind. Some regard it as insoluble. . [A]t the moment the neurobiological account is incomplete and there is an explanatory gap'. But there is, surely, more than just a gap that a more complete knowledge of the brain may one day fill, because no knowledge of the workings of the neural networks, however complete, can convert correlation into identity. Damasio himself is clear that he and his colleagues are researching the ‘neural underpinnings' of consciousness, ‘the neural architecture which supports consciousness', but not consciousness itself.

Once this is accepted, the door is open to a huge range of possibilities that were automatically excluded by the widespread naturalistic assumption. That assumption has long been, for us in the industrialised west, a paradigm so firmly fixed in our minds that we do not so much see it as see everything through it. However if we have to accept that the universe includes the non-physical reality of consciousness, and no doubt also a huge range of unconscious mental life, as well as the physical reality of matter, then the materialist or physicalist assumption becomes a ghost to be exorcised. This does not of course entail a religious interpretation of the universe, but it does show that such an interpretation is an open possibility, not to be excluded on the mistaken ground that it has been ruled out by the sciences. And any re-formed naturalism will have to be much more complex and sophisticated than the old version.

Moving now within the realm of religious possibilities, and still on the culturally forbidden subject of death, we are confronted by two very different options. Most westerners, whether they accept, or more often reject, the idea of a life after death think in terms of an eternal heaven and hell. For most easteners, on the other hand, what they either accept or reject is the idea of a journey through many lives. Which of these options is for us the standard idea to be either accepted or rejected depends in the great majority of cases on where we were born. However philosophy, in contrast to theology, tries to transcend this global postcode lottery. And it seems to me that, given the possibility of more life than the present one, then from a religious point of view the eastern model is to be preferred. For at the end of this short life very few, if indeed any, are ready for either eternal bliss or eternal punishment. But on the other hand all are ready for further growth and development. And if such a process is indeed taking place, we are all clearly at an early stage in it. If it is to proceed it requires further interactions with others within a common environment. It seems that this must take the form of further mortal lives, lived within the boundaries of birth and death, because it is the inexorable pressure of these boundaries that gives life the urgency that an unlimited horizonless future would lack. The cosmic scenario that best meets these requirements is some form of the concept of rebirth or reincarnation. So this is the option that I now want to explore a little.

Let me bring in at this point Milan Kundera's strange but striking novel The Unbearable Lightness of Being. At one point he has his central character Tomas reflect as follows: ‘Somewhere out in space there was another planet where all people would be born again. They would be fully aware of the life they had spent on earth and of all the experiences they had amassed here. And perhaps there was still another planet, where we would all be born a third time with the experience of our first two lives. And perhaps there were yet more planets, where mankind would be born one degree (one life) more mature. . . Of course we here on earth (planet number one, the planet of inexperience) can only fabricate vague fantasies of what will happen to man on those other planets. Will he be wiser? Is maturity within man's power? Can he attain it through repetition? Only [Kundera says] from the perspective of such a utopia is it possible to use the concepts of pessimism and optimism with full justification: an optimist is one who thinks that on planet number five the history of mankind will be less bloody. A pessimist is one who thinks otherwise'. This points very well to the sense in which, within the multiple lives option, religion involves the cosmic optimism which believes that through a series of lives in which any moral/spiritual maturing achieved in one is carried forward to the next, human existence will eventually be perfected. Each life story, and the human story as a whole, will lead eventually to a limitlessly good state. This cosmic optimism anticipates an end state that has a value in itself so great as to make worthwhile the long path that has led to it, so that in retrospect we will all be profoundly glad to have travelled it.

In Kundera's imagined scenario he looks forwards from human life as it now is to a supposed better future. But let us try the thought experiment of thinking back from that imagined future better state. Suppose that on the fifth planet human beings have become distinctly more caring towards one another, distinctly more inclined to care for their neighbour as much as for themselves, no longer able to be stirred to communal hatreds and wars, sharing the earth's resources equitably – by no means yet perfect beings in a perfect society but manifestly having moved in that direction. If we were part of that future world, and could see the emerging projectory, would we think that the earlier stages are now justified retrospectively by the increasingly better states to which they have led? We know what pain and suffering and despair and unhappiness there is in the world today. Would even this be justified within Kundera's imagined scenario?

I think that most of us, perhaps all of us, including those who now suffer most, would say Yes. We would all think that if that is indeed what is going on then we are glad to exist rather than not exist as part of this process. It is not a matter of a balancing compensation in the hereafter for pain suffered is this life but of the ultimate fulfilment of the human potential. In the course of this some may well have suffered much more than others – at any rate this is certainly the case within any one particular lifetime, - and yet all will have come by their own individual paths to the same end. Some may well have had a harder journey than others, and in this respect life may very well not be fair. It may be more like the situation in Jesus' parable of the workers in the vineyard who all receive the same reward even though some have done much more work than others. Further, in the scenario we are considering, it is not the case that the particular experiences which happen to each individual were specifically necessary to lead them to the future great good, or that the events of each person's life had to be just as they are, nor that the course of our lives is planned or directed by an omnipotent and loving God. Rather what happens occurs through the unpredictable interactions of very imperfect free beings. Remember that much the greater part of human suffering is caused by human actions or inactions. But whatever may be the largely accidental course of our life, or our many lives, it can – according to the religions - become the path by which we shall eventually have arrived at what John Bunyan symbolised in Christian terms as the Celestial City.

In both east and west the rebirth or reincarnation idea is popularly understood in an unsophisticated way as the present conscious self being born again in this world, including even sometimes being born in lower forms of animal life. But this popular picture is far from the conceptions found in some of the Buddhist and Hindu philosophies. These are themselves diverse, and there is no one official doctrine. But three major differences from the popular idea are fairly standard. The main one is that it is not the present conscious self that is re-embodied, not the persona gradually formed by the set of circumstances into which we are born - by our genetic inheritance, our various innate gifts and limitations, the family of which we are part, our short or long span of life, the region of the world and the society and culture and historical epoch in which we find ourselves, and the way things go in the world around us. That which is re-embodied in a future new conscious self is a deeper unconscious dispositional structure which Hindu philosophers speak of as the linga sharira, or subtle body – though this has to be understood within a whole philosophical framework in which it is not a body at all in our ordinary sense, - and which Buddhist philosophers speak of as a karmic bundle or complex. For them the conscious self is entirely evanescent, not an enduring substance. I suppose the most obvious Christian term for the deeper on-going self would be the soul. It is an aspect of our nature that exists far below the level of consciousness. All of the various factors in terms of which we live our conscious lives constitute, so the speak, the hand of cards which this deeper self has been dealt in this particular life, the stream of challenges and opportunities, capacities and limitations, with which life presents us. A major question, which I do not take up here, is whether or not some automatic process provides the reincarnating ‘soul' with a ‘hand of cards' appropriate to its need for further development. But what both affects and is affected by our basic dispositional structure is what the conscious personality makes of these cards. We are all the time both expressing and forming our deeper self by our responses to the circumstances, both agreeable and disagreeable, in which we find ourselves. And it is this cumulative quality of response that is built into the basic moral/spiritual character that will be re-embodied in another conscious personality.

The difference between Hindu and Buddhist understandings of rebirth is a topic which deserves further exploration. Broadly speaking, Hindus have taken a pessimistic view of the process, as involving further lives of suffering, whilst Buddhists take an optimistic view of it as a means of progress towards nirvana. (But there are exceptions. For example, Mahatma Gandhi, as a Hindu, had a more Buddhist outlook at this point).

Another difference from the popular conception is that our future lives may well not be lived on this earth or, as in Kundera's picture, on other planets of our solar system, or even other galaxies of our universe, but perhaps in the quite other spheres of existence of which Hindu and Buddhist philosophies speak. Or some of our lives may be lived in this world and some elsewhere. Each successive Dalai Lama, for example, is supposed to be a reincarnation of his predecessor, not only in this world but specifically in Tibet. But Buddhism also speaks of other spheres of existence within which life is carried on. If we ask where these realms are, meaning where in the only universe that we know, the answer is nowhere. The idea of other spaces has generally seemed in the west to be pure gratuitous imagining, but we may have to get used to the idea that there are things that are real although they don't exist in our customary sense. For the more we read those scientists who are trying to communicate with the rest of us, the more we are led to suspend many of our inherited assumptions. Sir Martin Rees, the Astronomer Royal, who is not himself a religious believer, in his book published last year, Our Cosmic Habitat, argues for the currently canvassed cosmological theory that this universe, beginning with its own big bang some thirteen billion years ago, is one of innumerable universes, among which there may well be many that sustain life, some more and some less advanced than the life on our own planet. He claims that ‘the multiverse concept is already part of empirical science'. Indeed the range of responsible scientific speculation is now greater and more exciting than it has ever been, and the possibilities that it opens up are much more mysterious and surprising than even a decade ago. Stephen Hawkins' recent account for lay readers of current scientific cosmology in The Universe in a Nutshell, also published last year, is far less dogmatic, far more conscious of surrounding mystery, than both the mainstream Christian theologies and the dogmatic naturalism of our time.

Returning to the multiple lives idea, yet another difference from the popular conception is that in the more philosophical eastern reincarnation, or rebirth, doctrines there is generally no conscious memory of previous lives, even though such supposed memories abound in popular folklore. As Gandhi wrote, ‘It is nature's kindness that we do not remember past births. Where is the good of knowing in detail the numberless births we have gone through? Life would be a burden if we carried such a tremendous load of memories'. A latent memory of the totality of our experience is however integral to the dispositional or karmic continuant which is expressed in each successive new conscious personality. There may or may not, as some claim, be occasional leakages of fragments of this complete memory into someone's consciousness. But normally not. However the full accumulation of memory nevertheless exists beneath normal consciousness. According to the traditional story, when the Buddha attained to full enlightenment during his night of deep meditation under the Bo tree at Bodh Gaya he remembered the complete succession of his previous lives. It is in virtue of this normally inaccessible thread of memory that the many lives are different moments in the same life project.

Returning now to Kundera, in his imagined scenario we do not now, in the first world, know what the future holds. Suppose however we had come to the belief that we are in fact taking part in a journey from world number one to world number five and then to yet further worlds beyond. Would not this change the way in which we experience and engage in our present life in world number one, the world as he says of immaturity? Would it not give a new and different meaning to what is now happening? Borrowing John Bunyan's image of life as a pilgrimage towards the Celestial City, the events on the journey, both its pleasant and joyful moments and its unpleasant and its terrible moments, have different meanings for the pilgrim who lives in faith in the reality of the Celestial City from that which it has for those who have no such faith. The cosmic optimism of the world religions consists in their picture of a larger process of which we are a part, such that we can live now in trust that, in Julian of Norwich's famous words of Jesus in her vision, ‘All shall be well, and all shall be well, and all manner of thing shall be well'. And in her vision Jesus adds, ‘Accept it now in faith and trust, and in the very end you will see truly, in fullness of joy'. An important aspect of religious faith within the great traditions consists in living now in trust of what Julian calls the ‘fullness of joy' to which we are moving. More generally, to quote a contemporary scholar, Mark Webb, ‘nearly all religious experiences result in the belief that the universe is an essentially friendly place; that is, that we shouldn't worry about the future'. Needless to say it is also true that, despite occasional vivid awarenesses of the essential friendliness of the universe in its totality, the ordinary religious person often gets caught in Bunyan's Doubting Castle, and falls into the Slough of Despond, and is bothered by both Mr Formalist and Mr Discontent, and gets waylaid in Vanity Fair, and indeed falls at some time into all the other dangers that meet us on life's pilgrimage.

This is the place to note that this basic cosmic optimism is marred within the monotheisms by their traditional doctrine of an eternal hell. And given the prior assumption that this present life is the only one there is, so that there is no possibility of continued maturing and moral growth beyond death – and the traditional doctrine of purgatory does not allow for this, - it is natural to think that some have proved themselves to be so wicked that their destiny can only be either hell or, more mercifully, annihilation. The fear of hell was of course also, notoriously, been used for many centuries as a tool of social control. Julian of Norwich was one of the minority of pre-modern Christian thinkers, and Jalaluldin Rumi a hundred years earlier one of the minority of Muslim thinkers, who have been hospitable to the idea of universal salvation; and it may well be significant that they were both mystics, that is to say experiencers, rather than writers of dogmatic theology. Buddhism and Hinduism, on the other hand, believing in many further lives to come, have much less need for an eternal hell. Their cosmologies do indeed include many states that are generally called hells, but these are states through which people pass, not to which they consigned for eternity. It may even be that we are in one of these now. But the cosmic optimism of these faiths, shared by various strands of Christianity, holds that the fundamental element of good at the core of our nature, the atman, or the universal Buddha nature, or the image of God within us, or ‘that of God in everyone', will eventually come to its complete fulfilment through the course of many lives, each bounded by birth and death and thus subject to the creative pressure of mortality.

Bringing all this to bear on the question of the meaning of our present lives, the hypothesis before us is that we are presently engaged in one phase, by no means necessarily the first, of a multi-life process of moral and spiritual growth within a universe which is, as the world religions affirm, ultimately benign or, speaking metaphorically, friendly. But how can it be said to be benign when it involves all the suffering, all the agony and despair, all the cruelty and wickedness that exist around us? Only, I think, if we grant the very high value of moral freedom and the consequent principle that goodness gradually created through our own free responses to ethically and physically challenging situations is enormously, we could even say infinitely, more valuable than a goodness implanted in us without any effort on our part. Putting this in the terms in which it appears in the intra-Christian theodicy debates, this is the Irenaean suggestion (as distinguished from the Augustinian theology) that God created humanity, not as already perfect beings who then disastrously fell, but as spiritually and morally immature creatures who are able to grow, through their own free decisions within a world that functions according to natural law and is not designed for their comfort, so that there are pains as well as pleasures, hardships to be endured, problems to be solved, difficult choices to be made, the possibility of real setbacks and accidents and of real failure and tragedy. The creative value of what is from our human point of view a very imperfect world is that only in such an environment can the highest human virtue come about of a love that is able to make sacrifices for others, the valuing of others equally with oneself. In a paradise in which there was no pain, in which nothing could go wrong, no one would be able either to help or to hurt another and there would consequently be no such thing as wrong action, and therefore no such thing as right action. But a world in which we can hate as well as love, wage wars as well as seeking peace, persecute and enslave as well as working for social justice, ignore one another as well as caring for one another, is a world in which moral choices are real and in which moral growth is possible and does in fact often occur. But – to voice the obvious objection – surely a loving God would not allow the extremities of human, and also animal, suffering that actually occur. The intra-Christian debate involves at this point the question whether God could intervene to prevent ‘man's inhumanity to man' or nature's perils without infringing either human freedom or the autonomy of the physical world. But since I am not postulating an omnipotent loving personal God, I leave that debate aside. I am postulating instead a cosmic process of which we are part, which we do not understand, which we often find to be harsh, sometimes extremely harsh, which we find to involve both great happinesses and great miseries, but which is nevertheless found in mystical experience within each of the great religions to be, from our human point of view, ultimately benign. And our reason tells us that this benign character must involve further living beyond our present life. When we try to spell out what this may involve we are still, however, dealing only in pareschatology, with what happens between now and the ultimate eschatological state. That state itself must lie beyond even our present imagining.