In December1965 the Second Vatican Council declared (Gaudium et Spes 18) ‘It is in regard to death that man's condition is most shrouded in doubt’. That may seem an overstatement. There is certainly doubt, but is death the most mysterious thing about our human condition? What is death?

Doctors transplant organs, including hearts. To remove the heart of a living person is to kill that person, something doctors are unwilling to do, despite the growing demand for euthanasia. It was formerly thought that when your heart stops beating and your blood ceases to circulate you die, but it is now recognised that the circulation of the blood, which is necessary for other vital functions like those of the brain and the lungs, may stop and restart, either spontaneously or through skilful human action. Doctors say, therefore, that you die, not when your heart stops, but when it stops and it is impossible for it to be restarted. To say that someone was dead but came back to life by some natural physical process (doctors do not take into account the possibility of a miracle) is, it is felt, to use the terms ‘dead’ and ‘life’ improperly. A person whose heart has stopped does not die until it is no longer possible for it to be restarted.Footnote ¹

Saying that death is an irreversible ceasing of circulation will not dispel all doubt about what it is because new methods of resuscitation may be discovered. Nevertheless defining death in this way is natural for doctors. It raises, however, an ethical question. If it is wrong to kill, but there is no moral obligation ‘officiously to keep alive’, is it wrong to withhold treatment which might restart circulation if this would be of no benefit to a patient? The ethical question does not arise over the transplanting of kidneys and other parts of the body, but it does over transplanting hearts. Here, as J.K. Mohindra saysFootnote ² it is natural to appeal to the principle of ‘Medical futility’. Mohindra distinguishes two kinds of medical futility: goal futility, when the goal cannot be achieved by the treatment, and value futility, where the goal can be achieved by it but is not worth achieving. If the goal of the treatment is restarting the circulation of the blood, it will be goal-futile if the patient has been decapitated or stabbed through the heart, but in the case of heart-transplants, it would have to be claimed that this would be of no value to the patient. Since blood-circulation is necessary for life, it might be thought that any treatment which restores it, even for a few seconds, is of value. Better grounds are needed for saying it is value-futile than a judgement that the patient's life is not worth living. Since human life involves sentience and the capacity for purposive acting and refraining, it could be said that treatment which cannot deliver that (perhaps because of other permanent brain damage or deficiency) is value-futile. Even, however, if satisfactory conditions can be formulated for determining whether the resuscitating treatment withheld is value-futile, it may be hard to claim that a heart donor from whom it is withheld is already dead and therefore not killed by the heart's removal. Mohindra suggests death might be defined as cessation of blood-circulation, when it is certain that it will not restart naturally, and it is certain that it will not be restarted, not only because there is no one available with the necessary skill, but also because, if there is someone available, the skill will not be used because using it would be futile. This definition would allow a surgeon to claim that a heart-donor whose heart is transplanted is really already dead at the time of the transplantation.

The question whether this redefinition of death is acceptable, though tricky, hardly justifies the claim in Gaudium et Spes. The words of the Council Fathers fit not doctors contemplating organ transplants but believing Christians who have a different conception of death.

To say that death is an irreversible cessation of circulation is not, in fact, to give a good definition of death. It is to say when death occurs rather than what it is. A good definition should tell us why we might want to know when it occurs; it should bring out the practical significance of death. In ordinary thinking death is the end of life. We think life begins at birth (or, as our biological knowledge progresses, with conception,) and ends with the irreversible cessation of vital functions. We also think that for living things, life and existence are the same: to exist is to live, and to cease to live is to cease to exist altogether. For Christians the human condition is shrouded in doubt because Christians believe that an irreversible cessation of bodily functions is not, or need not be, the end of our existence: at least for the virtuous, there is life, or at least existence, afterwards.

In the Old Testament the concept of a life after death for human beings is bound up with that of God. The earliest clear references to such life are comparatively late. In 2 Maccabees 7 the second Maccabaean brother says (7.9): ‘You are releasing us from the present life [to paron zên], but the king of the cosmos will retore us, after we have died for his laws, to eternal renewal of life [anabiôsis]’. He says nothing about those who have died otherwise than for God's laws, but in Daniel 12.2 we are told that ‘many’ who sleep in the earth will get up, some to eternal life [zôê aiônios], some to eternal shame [aiskhunê] and - the readings vary – to dissolution [diaspora] or reproach [oneidismos].

In Wisdom 2. 23-3.4 we read:

By the time of Christ belief in a life after death was well established, though not universal, among the Jews. In the Gospels, Christ is portrayed as bringing back to life the daughter of Jairus, the son of a widow of Nain, and Lazarus. Their vital functions have all ceased irreversibly, and are restored to them miraculously. Christ himself dies on the Cross; his death, Christians believe, was real and physically irreversible; but he returns to life. The life to which Christ restores Lazarus and the others is one that will terminate in irreversible death, but the life envisaged in 2 Maccabees, Daniel and Wisdom is conceived as unending. It cannot be terminated by physical action. So is the life promised by Christ in his teaching, and so, Christians believe, is Christ's own life after his resurrection. The life after death in which Christians believe is a kind of life different from life before it.

Some Jews of the first century believed, and Christ taught, that there is a life of happiness that is physically interminable, and that this is available, thanks to God, to the good who live according to God's laws. That is all, for practical purposes, that Christians need to believe about death. But it raises plenty of questions for theologians.

Does the physically irreversible ceasing of vital functions, involve ceasing to exist? The Jews spoke of Sheol or, in Greek, of Hades, as a place of the dead, and early creeds speak of Christ as descending, after death, to Hades or the lower regions – in Latin inferna, inferi. Going to a place of the dead seems to require continued existence, but the use of such terms, such as ‘the Deadlands’, might be euphemism for ceasing to exist. Existing in Sheol is certainly not the life after death to which Jews looked forward, and it is unclear what it might consist in; the Jews did not embrace the vivid picture offered by Homer in Odyssey 11 and 24.

The life after death to which Jews looked forward was a life of the same person as the one who had died. In the natural world motion involves spatio-temporal continuity, and a physical object that is identical with one identified at an earlier time exists throughout the interval. For that reason Jews may have thought that there is a place of the dead, a Sheol, where the virtuous exist until they are resurrected. We allow a gappy existence to artifacts. If a chair falls to pieces and can no longer serve its function and support a sitter, it ceases to exist; but if we manage to reassemble the pieces, we may say it returns to existence and is the same chair. Ezekiel 37 with its bones depicts the revival rather of a nation than of individuals, but people may have thought that the continuous existence of human bones might suffice to ensure the identity of resurrected persons with those whose bones they had been, and not reflected that the bones of later virtuous persons might have been formed out of material that formed part of the bodies of virtuous predecessors. Christians may feel a special uneasiness about saying that Christ's death on the cross was his ceasing to exist. Was the incarnate Word non-existent between Friday afternoon and Sunday morning or did Christ merely go elsewhere as he did from Bethany after raising Lazarus?

Spatio-temporal identity is necessary for natural physical motion, but not for identity. Nothing is. Sameness and otherness, two of Plato's Greatest Kinds, are, so to speak, brute facts, and presuppositions of rational thought. In the Gospels the risen Christ appears at different places at different times, and could have been the same person without existing anywhere in the spatio-temporal world during the intervals. Life after death was conceived as involving vital human functions. The risen Christ walked, spoke, ate, and cooked; these actions are bodily; they depend on vital functions, and they convinced those who saw him that he was really alive with human life; but they were necessary for his existence to be human, not for it to be that of the same individual.

Christians might have another reason for hesitating to say that Christ ceased to exist. They might think that he raised himself in the same way as he raised Lazarus. Not only, however, did he, unlike Lazarus, rise to a supernatural life; it is a mistake to say he raised himself at all. His resurrection, like that to which the Jews before him (and Martha in John 11. 24) looked forward, was the work of God and a reward for doing what God wished (Matthew 26. 39–42), for ‘obedience unto death’ (Philippians 2. 8), that is, unto non-existence. His death on the Cross yielded the first fruits of divine salvation from death (1 Corinthians 15. 20–24). Through it supernatural and eternal life was given to all human beings to whom God gives it, including Abraham (cf. John 8. 56–8) and others who lived before Christ. All who have eternal life with God, Christians are taught, have it by sharing in Christ's resurrection.

Jews and Christians believe that endless life after death is given by God to people who do God's will. What, a theologian may wonder, about those who don't do God's will? Is physical death the end of existence for them, or do they too have unending life, though not one of happiness with God?

Wisdom 2. 23 says that God created human beings for indestructibility. That implies that a life immune to destructive causal action was part of the Creator's plan for human beings, but it does not make it clear whether, though it is part of being human to be liable to physical death, it is also part of being human to have a kind of existence not terminable by physical action, or whether being human is at most a sufficient condition for being able to live in a way that God can reward unending life.

Christians have often believed that all human beings, both good and bad, have unending life, but the grounds in the Bible for this view are far from solid. Paul in 1 Corinthians 15. 50–4 emphasises the natural mortality of flesh and blood. In the description of the creation of human beings in Genesis 1 they are not distinguished from animals and plants in having a life that is unending. They are distinguished in being made in the image of God, but their similarity to God is put alongside their being male and female, and the difference between male and female is important in mortal species, but may seem superfluous in immortals. It is present in Greek mythology, but the Jewish God is not like Zeus or Aphrodite. It is not said that human beings are like God in having a kind of life that is unending. On the contrary, in Genesis 2–3, where Adam is produced before Eve, far from being told that Adam had unending life, we are told that that he and Eve did not eat of the tree of life at all; they were made to leave the garden where it grew because they had already become like God in ‘knowing the difference between good and evil’, that is, in intelligence (the Jews saw the highest form of intelligence, ‘wisdom’ or sophia, as moral knowledge rather than natural science or mathematics), and God did not wish them to live for ever (Genesis 3. 22) – a further way of becoming like him. In the Pentateuch the theological teaching is implicit, and it is hard to claim that anything in it implies that it is natural for human beings to live on after physical death. The rewards promised to those who obeyed God's laws belong to the natural order: victory over enemies, long life, abundant progeny and milk and honey (Deuteronomy 6. 1–3). At the time of Christ many Jews who were committed to upholding Mosaic law, including, apparently, leading members of priestly families, did not believe there was any resurrection.

In the later books of the Old Testament Elijah and Elisha both restore life to persons who have died physically, but the life restored is expected to have an end. The ascent of Elijah himself to Heaven in a whirlwind, apparently without return, is not related in 2 Kings 2. 7–13 as a fate in store for everyone. These miracles might be understood rather as proving the existence of God and the authority of his prophets than that unending existence is possible for human beings. We are often warned that evil-doers will end badly, and Wisdom 3.18 speaks of a day of ‘judgement’ [diagnôsis]. Their punishment, however, appears in Wisdom 4 and 5 to belong to the physical order, and so may their judgement: they have no descendants, their achievements pass away, they themselves are forgotten. The belief attributed to the ungodly [asebeis] in Wisdom 2. 1–5, that physical death is ceasing to exist altogether, could have been thought true of them.

The main scriptural support for the belief that human beings naturally live for ever is in Matthew's Gospel. In the account of the Last Judgement in Matthew 25. 31–46 the goats stationed on the left are told to go to eternal [aiônion] fire made ready for the Devil and his angels. This description takes up the interpretation of the parable of the darnel in Matthew 13. 37–42. The harvest-time stands for the end of time [sunteleia aiônos]. The Son will send out his angels, they will collect the evil-doers and throw them into the fiery furnace, where there will be weeping and gnashing of teeth. In Matthew 8. 8–9 it is said that it is better to enter life with one hand, foot or eye than to be thrown with two into eternal fire. And in Matthew's narrative of the parable of the king's wedding feast, at 22. 12–13 the guest without a wedding garment is bound hand and foot and thrown into outer darkness where there is weeping and gnashing of teeth.

This can be taken to imply that those who do not, with God's blessing, take possession of the kingdom made ready for them from the beginning of the cosmos, will all still have unending life in some kind of fire. The darkness, also, weeping and tooth-gnashing are part of life after death for the wicked. Mark, though in his description of the Last Judgement at 13.27 only the elect are present, speaks at 9.43-9, where he repeats the advice of Matthew about bodily parts, of fire that is ‘unquenched’. The wicked are similarly threatened with weeping and tooth-gnashing at Luke 13.28, and in Luke's report of the rich man and Lazarus (16. 19–31) the rich man is alive after death in Hades no less than Lazarus with Abraham.

In the New Testament fire is associated with two functions. One, mentioned in 1 Corinthians 3.13-15 and 1 Peter 1.7 (and also in Malachi 3.2,), but not envisaged in the Gospels, is the purification of precious metals. The other is the disposal of unwanted vegetation: darnel in Matthew 13.30-44, branches that do not bear fruit in John 15.6. Fire which gets rid of useless vegetation does not go on for ever, but brings the darnel or the branches, like the chaff, spray and, smoke mentioned in Wisdom 5.14, to an end altogether. It is not impossible that the fire called ‘eternal’ by Matthew and ‘unquenched’ by Mark is so called to emphasise the finality with which it gets rid of the wicked; it does not leave them still in existence, agonised but unconsumed.

In John's Gospel there are 15 references to eternal life, zôê aiônios or life eis ton aiôna, but usually as somehow conditional: on believing (3.15; 3.16; 3.36; 5.24; 6.40; 6.47), on recognising God and Christ (17.3), on water received from Christ (4.14; 17.2), on certain food (6.2; 6.51; 6.54), on being Christ's sheep (10.28), on the Father's commands (12.50). The exception is 5.39, where people are warned against thinking it can be found in the scriptures, but not doing as the scriptures say. John has less to say about the fate of evil-doers after death. He speaks of ‘judging’ [krinein], and says (5.24) that the Father has given the Son power to pass judgment [exousia krisin poiein], but he does not describe a formal trial on the Last Day. ‘Judging’ for him seems to be synonymous with condemning: so 3.17-19; 12.47, 16.8-11. Those who believe escape judgment altogether (5.24), and resurrection to judgment is an alternative to resurrection to life (5.28) rather than a preliminary to judicial proceedings. Most Jews may have thought that dead evil-doers, though justice required them to be raised in order to learn why, would rise to annihilation.

John has a fairly clear theology of life after death. In the beginning was the Logos and in it was life [zôê] (1.1-4). Though logos is translated ‘word’ it means speech rather than a word that is used in speech. It is through speaking that God in Genesis 1.3 created the natural order. Those who receive the incarnate Logos are given the power [exousia] to become children of God (1.12). In order to see or enter the kingdom of God, it is necessary to be born from above through water and the Spirit (32.5). Death, in ordinary speech, is contrasted not only with life but with birth, and although, as I said, if we speak strictly, our existence begins not with birth but with conception, in figurative speech we need not distinguish the two. The rebirth of which Christ speaks in John 3 is a beginning to exist supernaturally. The comparison is not made in the Gospel, but the supernatural life of those persons who are still physically alive may be compared with the physical life of those children still in the womb: it is the same kind of life as that of the risen, but much more constrained. The Father raises the dead and makes [sc. them] alive [zôopoiei], and the Son makes alive those he wishes to (5.21). He who hears Christ's speech and believes in the one who sent him has eternal life (5.24). As the Father has life in himself, so he has granted it to the Son to have life in himself (5.27; cf. 17.2: the Father has given the Son power [exousia] over all flesh, so that he in turn may give life to all those the Father has given him as his subjects.)

In 6.26-58, when Christ is taking up the statement in 5.39 about people looking for eternal life in the scriptures, he refers to Exodus 16 and the manna from God, and says (6.32-5) that the Father gives the true bread [artos] that gives life to the cosmos; and he goes on to say that he himself is the bread of life (6.48), the living bread (6.51), and that whoever eats of this bread will live for ever. It might be that Christ means simply that his words are life-giving bread, more life-giving than the scriptures, but he goes on to insist in a literal interpretation (6.55-6): ‘My flesh is true food [brôsis] and my blood is true drink [posis]. The person who chews [trôgôn] my flesh and drinks my blood remains in me and I in him’. These and the following words are naturally taken to anticipate the institution of the Eucharist. In John 17, the final discourse to the apostles, Christ prays not only for those present but for all who have faith in him through the words of those present, ‘that they may all be one, as you, Father, are one in me and I in you, in order that they too may be in us … And I have given them the glory [doxa] which you have given me, in order that they may be one as we are one: I in them and you in me, so that they may have been completed [teteleiômenoi] into one’ (17.20-23, cf. 17.11).

There is no distinction here between life after death and supernatural life received from or through Christ; no suggestion that there is a life after death that is natural for human beings. Nor is there any distinction between the supernatural life that comes from or through Christ, and the divine life of Christ himself. Just as a branch cannot bear fruit by itself but must remain in the vine, so we can do nothing unless we remain in Christ (15.4-5), sharing his life, and his life is life in oneness with the Father; those who have it must be one both with Christ and with one another (17.21-3). Christians praying for Christan unity are inclined to model it on the unity of a human society, a happy family, or a peaceful country; but the words of John 17 (and words of Paul like those in Acts 17.28 and Romans 6.23) suggest something closer than that.

This survey of Biblical texts suggests that physical death is not only the end of physical life but the natural end of existence for living organisms. If evil-doers come alive to be judged, the restoration to existence could be momentary. Plato attributes to the popular sophist Hippias the view that the best a man can hope for is ‘to be rich, healthy, honoured by his countrymen, to reach old age, and, after burying his parents handsomely, himself to be given a fine, impressive funeral by his descendants’ (Hippias Major 291 d-e), and before the advent of Christianity it is probable that this opinion was widely held, though classical mythology aired the possibility that some human beings, such as Hercules and Castor, and even some animals might be given an existence after death as a supernatural favour. But Christians today are inclined to say that all human beings have immortal souls and take this to mean that they themselves will live for ever, either in bliss or in agony. Where does this idea come from?

In ordinary thinking, I have suggested, death is conceived as the end of life, and life as existence for living things. In the Phaedo, however, Plato formulates (64 c) a completely different definition of death:

Plato's words have had a powerful influence on European thought. The word we translate ‘soul’, psukhê or psyche, was in common use in antiquity. It could be used, as in Matthew 25–6 and Luke 14.26, for life itself; as by St Paul in contrast with spirit, pneuma, for sensuous, emotional life, as distinct from ‘spiritual’ and perhaps intellectual life (1 Corinthians 15.44-6); or, as by Homer (Odyssey, Books 11 and 24), for a ghost or shadowy remnant of a human being. Plato uses it for a kind of subsistent thing, a separable component of a human being. He goes on to identify Socrates's soul with Socrates himself (‘If you can catch me’, Phaedo 115 c), and he has no doubts about an after-life for evil doers – ‘If death were a release from everything it would be a godsend [hermaion] to the wicked to die’ (Phaedo 107 c). In Republic 10 614 c he describes a post mortem judgement not unlike Matthew's. Judges are seated in a place belonging to the gods [daimonion], with shafts leading up to heaven and down into the earth; and the judges ‘tell the just to go to the right and up and through heaven … and the unjust to go to the left and down’. In Gorgias 525 a-c he divides evil-doers into those who are curable and get their wickedness purged away through pain, and the incurables who ‘undergo the greatest, most agonising and terrifying sufferings for all of time’, as examples or warnings.

Plato's conception of life after death differs from that of the Jews not primarily in that he thinks it comes to good and bad alike, but in its independence of the idea of God and in his dualistic conception of human beings, patent in his definition of death, as consisting of two separable things, comparable, to use his own example, to a weaver and his coat. Why did he think we are composites of a soul and a body? A good description of any object will consist of words or phrases which can be uttered separately and have separate meanings; but it does not follow that the thing described consists of separable components signified by those words. To take an Aristotelian example, ‘a house’ signifies a shelter for human beings composed (unlike a tent) of solid materials such as stones, beams, and tiles. Plato would have agreed that a house itself is not a composite of building materials and a shelter, and denied that when it ceases to exist the shelter and the building materials exist separately. A reflective non-philosopher might think that a human being is an intelligent, purposive agent made up of flesh and bones, or perhaps of head, body, arms and legs; why did Plato think that the death of a human being is the coming to exist separately of an intelligent purposive agent and bodily parts of flesh and bones?

Unlike the Jews, Plato accepted transmigration of souls; he thought that our souls existed before they entered our bodies, either on their own or in other bodies. This, however, was rather a corollary of his dualistic conception than a ground for it. His principal ground was probably that human beings are intelligent. In Phaedrus 245 c-e he speaks of the soul as a thing which is a source of change in itself, something that might be said of any living thing, even a plant; in Theaetetus 184–6, however, he distinguishes sentience from intelligence: sentience depends on bodily parts that are sensitive to light and colours, sounds, flavours, and other sensible properties, whereas intelligence, he thought, does not. The words we use in intelligent speech, in asserting, denying, comparing, inferring, relating causally and temporally – words such as ‘is’, ‘not’, ‘same’ other’, ‘equal’, ‘before’, and ‘because’ - do not (as do ‘yellow’, ‘high-pitched’, and ‘sweet’) signify anything physical. Plato thought that grasping the meaning of such words can have no physical explanation; either we have always have known the things they signify, or we must have learnt what those things are before we become embodied and now recall the knowledge. The ‘we’ that use these words and speak intelligently must be non-bodily persons. This thinking reappears in the Catholic teaching that the intelligent soul, the anima intellectiva, (a phrase used in Denzinger-Schonmetzer 1440 for what Aristotle at De Anima 3 429a10-11 calls ‘that part of the soul with which the soul gets to know and thinks’) is immortal and ‘immediately created by God’ (Denzinger-Schonmetzer 3896).

Plato's thinking does not appeal to philosophers today. Philosophers now mostly accept that intelligent organisms evolved out of sentient, and that intelligence developed naturally with language. The Jews in classical antiquity, like the ancient Greeks, had no idea of evolution. They thought that human beings were immediately created, male and female, as a species by God, and it would not be incompatible with Jewish thought that a species should be created immortal. Although the author of Genesis 1 did not, I suggested, in fact think this about human beings, there is something in first century Jewish thought which is comparable with Plato's idea of non-bodily existence. God at Genesis 1.3 created the spatio-temporal world by speaking. In speech, as we read in John 1.4, there was life. In due course the speech became flesh, and pitched its tent in us, eskênôsen en hêmin. These words can be understood to mean simply that God came to dwell among us in our spatio-temporal world. But they can be taken more literally: God came to make a temporary residence in individual human beings: first, no doubt, in the Virgin Mary when she said ‘let it come about to me as you say’, but then to those who accepted the logos, to whom it gave the power to become children of God (John 1.12). The Jews thought that human beings are naturally intelligent: Adam and Eve learnt naturally, without divine assistance (Genesis 3.11), through speech with creatures (the serpent and each other) to differentiate good and evil; but becoming children of God required the incarnation; Plato thought that it is natural for human beings to be immortal, but intelligence transcends the physical order.

Over the centuries a dualistic account of human beings has appealed to thinkers both Christian and non-Christian, and has never been condemned by a Council of the Church. The emperor Hadrian said in a poem about death:

Shakespeare wrote in his Sonnet 146:

And a Platonic account is certainly suggested by ‘The spiritual soul does not come from one's parents but is immortal. It does not perish at the moment when it is separated from the body in death’ (Catechism of the Catholic Church: Compendium s. 70), These words, indeed, suggest that we consist not just of two but of three subsistent entities, a body, a non-spiritual soul which perhaps does come from our parents, and a ‘spiritual’ or ‘intellective’ soul that is ‘immediately’ created by God and then inserted into a living ovum at some stage in its natural development.

Perhaps Christian teaching authorities should not pronounce on an issue which belongs more to philosophy than to theology. Christians in the second century will have been heartened to find in Plato an ally on central Christian doctrines. It is otherwise today. However much they may admire Plato's philosophy of mind and philosophy of language, reflective Christians may prefer a Jewish approach to life after death. Physical death, they may say, is the natural end of existence for any living organism. The belief that living things evolved out of inanimate matter, and intelligent life out of sentient, has given us a different conception of nature from that of those who saw it as an aggregate of separate creations. We now view the spatio-temporal world as an evolving unity held together by physical laws, and any product of nature must be subject to those laws and destructible. When it was thought that nature is an aggregate of separate creations, it was easy to think that a spatio-temporal species might be created immortal. But if the spatio-temporal order, the only created order of which we know, is a unity, perhaps the only kind of existence immune to physical destruction is that of the Creator, and creatures can have it only through sharing in the existence of the eternal Creator.

This can be seen, however, as a supernatural development of the natural order. In that order life, sentience, and purpose emerge from inanimate material. Sentient awareness and purpose depend on causal processes, on sensitivity of organisms to action upon them by other things, and upon a storage capacity for memory and control of limbs, but a new, non-causal kind of explanation comes to apply; their behaviour is explained as awareness of their surroundings and desire or fear. Intelligence emerges from sentience (philosophers now mostly think) through society and speech. Human beings act and refrain from acting for reasons of which they are conscious. We are aware of acting and refraining for negative reasons, because of what is not the case, as well because of what is. We relate past and future; we attribute not only causal powers but awareness of things, desire and fear or aversion to others; and we act and refrain from acting in order to benefit others as well as to benefit ourselves as solitary individuals. This intelligent thought is mediated by language, which enables us to express negative states of affairs and to be conscious at the same time of things that exist or occur at different times. The evangelist John does not explicitly discuss the relation of intelligence to speech, but in attributing life to speech at 1.4, if he has in mind intelligent life, he is in step with modern philosophers.

Many philosophers and psychologists today think that only causal explanation is genuinely explanatory. They think that the bodily movements we count as purposive are caused by beliefs, desires and fears or aversions and that our beliefs, desires and fears are themselves caused by causal action on our bodies by other things. Belief, desire and fear are modes of consciousness or thought, and how causal action can cause modes of consciousness or modes of consciousness cause bodily movements are admitted to be ‘hard’ questions.Footnote ³ Human behaviour, however, can be thought of in two ways: as movements that are made or prevented, or as the making or not making of movements. Thought of in the first way they are causally explainable; thought of in the second they are thought of as purposive or purposeless. We can think of them in both ways, but not at the same time. Thought of in the second way and as purposive, they are thought of as awareness of reasons, and as desire for or fear of possible outcomes. And these different ways of thinking can both be right.

The Jews came to believe not only that God commanded them to act and refrain in certain ways but that his purpose in these commands was not to benefit himself but to benefit them and through them all living creatures. This purpose of God came to be recognised by the Jews as a purpose for them, too. Insofar as they acted to achieve it, their behaviour was no longer purely natural: it was an exercise not just of natural intelligence, but of what came to be called ‘faith’. ‘Since grace’, says Aquinas (Summa Theologiae 1a q.1 art. 8 ad 2) ‘does not do away with nature but perfects it, natural intelligence should be subservient to faith’. Discussing faith in Summa Theologiae 2a 2ae q. 2 art. 3 he says ‘The perfection of a rational creature consists not only in what belongs to it according to its nature, but also in what is attributed to it from a certain supernatural participation in divine goodness’. Aquinas does not formulate the analogy, but he sees faith, I suggest, as standing to natural practical intelligence as natural practical intelligence stands to sentience.

Natural intelligence concerns beliefs about things that are part of the natural order. The Jews came only gradually to recognise that their God, though he controlled the natural order, differed from the gods of other nations in not being part of it. The gods of other nations might be powerful, but their purposes were natural, like the purposes of human beings, and could be understood in the same way. They themselves could be gratified or offended, angered or placated, in the same way as intelligent creatures. The Jews thought at first in that manner of their own God; ridding themselves of anthropomorphism came late. I said that the earliest evidence in the Old Testament of belief in life after death is comparatively late; I suggest that it went with conceiving God as the external source of the natural order, not as himself a spatio-temporal being.

It used to be thought that natural intelligence is peculiar to our species; a sharp division was made between non-human animals that are merely sentient and human beings. Signs of sagacity in domesticated dogs and birds was discounted. Aristotle, however, emphasised the continuity running through the whole of nature from the inanimate to animals, with no discernible dividing-line [methorion] (Historia Animalium 8. 588b4-6). Even if intelligence is limited to human beings, there is no sharp division between the time when children do not yet act intelligently and the time when they do; and today, when much more is known than formerly about the hominid predecessors of homo sapiens, anthropologists may well hesitate to say when intelligence entered hominids. It is similar, we may think, with faith. Paul attributes faith to Abraham (Romans 4.1-3), and it might well be attributed to the Maccabaean brothers. But the notion becomes explicit and is expressed by the words pistis, pisteuein in the New Testament.

Faith is attributed to Mary by Elizabeth in Luke 1.45 for ‘believing there would be complete accomplishment of the things said to her by the Lord’. It is constantly on the lips of Christ, for instance in Matthew 8.10, in passages I have cited from John, and most noticeably in Paul, for instance Romans 4, Hebrews 11. Faith as understood by Paul is quite different from rational belief and trust such as we have in other human beings and institutions. It is, as he says in 1 Corinthians 17–26 (where ‘wisdom’, sophia, means not so much theoretical or academic knowledge as natural practical intelligence) ‘craziness’ [môria] to those without it. So, a Christian might say, would human intelligence seem like craziness to a trout or a mayfly.

The rationality of someone with faith involves acting for reasons that are beliefs about a being not accessible to the kind of knowledge we have of physical objects. We think that human beings can act to benefit other living things, independently of any benefit to themselves, but we can understand this as a purpose, something beneficial, for any intelligent social creature; we see unselfish action as harmonising to a greater or less extent with respect for the customs of our society and the pursuit of benefits to ourselves as solitary individuals. God's desire to benefit creatures cannot be seen in this way. God is not a social being independently of incarnation. Nor can action to behave as he wants us to behave be rationalised in the same way as action to behave as other creatures want us to. When we act to benefit other creatures, we have knowledge through our senses of their existence and of what is beneficial to them. We have no such knowledge of God through our senses. We know what he wants of us through his telling us, and such knowledge of his present actual existence as we have is not just speculation about the origin of the natural order but inference from his interventions in the natural order, his miraculous utterances and deeds. That was the basis of Jewish belief in God, whereas in our ordinary intelligent inferences we discount the miraculous. Faith in God is quite different from faith in a human friend; it is either an inferior or a superior kind of rationality.

All genuine belief is inseparable from behaviour. That goes for sentient belief such as an animal's perception of something as food or as an enemy or a friend, and also for natural intelligent belief. If there can be intelligent faith in God it will be expressed, as the apostle James emphasises, James 2. 14–23, not just in reciting creeds but in practical action which goes beyond what is natural, behaviour such as Abraham's offering as a sacrifice the son he so much desired, such as Mary's accepting a son without a human father, such as Christ's passion and death. The miraculous element in faith does not make it irrational if it expressed in behaviour which is itself supernatural; though that too is a matter for judgement.

Christians believe that insofar as we act and refrain from acting for God's purposes, we are already identifying ourselves with God and living in a supernatural way. They believe that God actually gives, to those who accept it, his own supernatural life. The supernatural life is constrained at first by the physical laws of spatio-temporal nature, and while we remain subject to those physical laws it may be terminated by sin, by behaving in a way contrary to God's purposes as we understand them. If we remain faithful, irreversible failure of body functions is not the end of our existence. Our existence continues in union with God's. But God's timeless existence is not temporally related to that of spatio-temporal creatures. If Abraham's faith was rewarded with a share in it, the irreversible failure of his bodily functions was not the end of his existence, even if that failure occurred before Christ's offering of his own existence on the Cross. We cannot say that the virtuous dead exist contemporaneously with us. Instead, however, of saying that death is the coming apart of a soul and a body, we may say that it is the natural end of existence for any living organism, but that for those creatures whom God has already endowed with his own supernatural life, it is a release from the womb of nature into the light of perpetual day.