You were born in 1934 in the West Midlands of England. Can you tell us what your childhood was like?

I was an only child. My father then taught music in a high school. Later he became the Essex county music advisor, and after that he became head of a new music department in a technical college and also ran an advanced music school in connection with the music life of Aldeburgh, in which Benjamin Britten and Peter Pears were involved. My mother looked after the home until I was about 11. I spent most of the year when I was 10 in bed, because I was suspected of having tuberculosis, and the cure for that in those days was to rest. But from the age of 11 until I left school, I went to boarding school, and was at home only in the school holidays. My mother then resumed her work as a full-time secretary, which she had been before my birth. She believed that the way to get on in the world was to have a proper ‘public school’ (in the British sense of ‘private school’!) education. She may have been right about this, given how things were in the 1940s. So I went to a ‘prep school’ for a year and a half. And then I got a scholarship, which covered about a third of the fees, to a well-known public school, Charterhouse. And there I remained for five years. After I went to boarding school, I lost touch with my former school friends, and had no friends at home in the school holidays. Because of my suspected tuberculosis, for most of my time at school I didn’t take part in all the sporting activities, and that made some of my contemporaries look down on me as a ‘weed’. Also, most of my contemporaries at Charterhouse were the sons of fairly prosperous parents, whereas I came from a modest background. For these two reasons I didn’t fit in very well in Charterhouse, but it did provide a very good academic education.

How much of a role did Christianity play in your upbringing?

Neither of my parents were religious. But my mother felt that I ought to know what religion is. So occasionally she took me to church. But I have believed in God for as long as I can remember. I don’t know who encouraged me to do so. But I was conscious of differing from my parents, and so hid it from them that I was saying my prayers.

When you went study at Oxford, and this would have been in the 1950s, what was the atmosphere like in philosophy circles at that time? What sort of ideas were popular among Oxford philosophers?

I got an ‘open scholarship’ to Oxford. In those days that was the most prestigious way to gain admission to Oxford, because it meant that Oxford, rather than some local education authority, paid the fees. Scholars wore a different sort of gown from other undergraduates. I studied for a B.A. in Philosophy, Politics, and Economics (PPE). I did not choose PPE because I was interested in philosophy. I was interested in philosophy, but I was even more interested in politics and economics at that time. But I soon realised that philosophy was what I wanted to specialise in. What was the atmosphere? ‘Ordinary-language philosophy’ and the rather more common ‘logical positivism’ between them dominated the Anglo-American philosophical world. In Oxford, under the influence of J.L. Austin, it was ordinary-language philosophy which was the dominant influence. Austin ran a class on Saturday mornings for faculty members. Rumour has it that it consisted in him telling faculty members the answers to various philosophical questions. Austin was very acute. That comes out in Sense and Sensibilia, a book in which he rubbishes A.J. Ayer’s views. I realised that he was very good at the kind of philosophy he practised. When I became a graduate student I went to his classes quite a bit. The one I remember was a class called ‘Excuses’. What we did each week was to take a different adverb whereby you make an excuse for doing something: ‘I didn’t do it deliberately’; ‘I didn’t do it on purpose’; ‘I didn’t do it voluntarily’. Each week we’d consider what it would mean to say, ‘I didn’t do it [followed by the week’s adverb]’. We examined how these words were used in normal discussion and charted that. And we did it very well. But I had the sense, and I don’t know how many other people had the sense, to realise that there were philosophical questions which are a bit deeper than these questions about the ordinary use of words. I had the hope that philosophy of some kind might turn out to be useful in connection with religion, because by that time I had come to feel that I was called to be a priest. The current ‘ordinary language’ philosophy tended to say of religion only that ‘this is a rather antique speech-act game, which we don’t play’. It also had little to say about science, of which it was extraordinarily ignorant. There was hardly any philosophy of science studied in Oxford. There was a lecturer in the philosophy of science, and that was Friedrich Waismann, who was at one time a member of the Vienna circle. I went to his lectures, and I found these the most inspiring lectures I attended. He talked about space and time and the relevance to them of relativity theory. And that got me very interested in those philosophical topics. So, both because I was very interested in it and because I thought it might have application to religion, I went on to study for the 2-year graduate course at Oxford known as the ‘B.Phil’ in Philosophy.

You said that you had a sense at one point that you felt called to be a priest. What changed such that you ended up taking an academic career track?

I realised that it was very important to have a rational defence of religion, yet the typical theology of those days held that ‘religion is entirely a matter of faith; you enter into religion, and you mustn’t expect arguments, because that is demeaning to God’. And I thought that wouldn’t do. The educated world was looking for a rather better answer than that and I thought that by becoming an academic philosopher, I might be able to help to provide that answer.

During that time there were the beginnings of a renaissance of religious philosophy going on over the other side of the Atlantic, which seems to have been driven by the move of saying that it’s quite a lot easier to have epistemic justification than was once held, with the thought being that perhaps it’s also easier to have justified religious beliefs than was once held. But that wasn’t seemingly what gave impetus to your interest in philosophy of religion. Could you tell me about what initially did inspire your approach to philosophical questions about God and religion?

During the period of my life I have just discussed, I wasn’t conscious that even on the other side of the Atlantic there was much philosophy of religion. Alvin Plantinga’s book God and Other Minds was published in the late 60s. But I wasn’t immediately aware of it. I thought that the paradigm of knowledge for the outside world was science. As I said, it seemed to me that philosophers were entirely ignoring science. I felt that what was needed was to connect religious views with this paradigm of knowledge. For that reason, I spent the first ten years of my philosophical career mainly teaching and writing about philosophy of science. My first book, Space and Time, was to a considerable extent about Relativity theory. And my second main book, An Introduction to Confirmation Theory, was about probability and in particular the different degrees of probability ascribable to scientific theories. That’s why I investigated this, because the world saw science as the paradigm of knowledge; and if religion was to be defended rationally, it had to fit into that paradigm.

You went on to build a cumulative case for the existence of God, in which you claimed that various items of evidence are much more strongly predicted by the hypothesis of theism than by the hypothesis of atheism. If you had to pick out one or two items of evidence from that cumulative case that you find especially compelling, which would they be and why?

In the books concerned merely with the existence of God, and not with any specifically Christian doctrines, I drew attention to four phenomena: the existence of a large physical universe; the universe being governed by simple laws of nature; these laws being such as to lead to the evolution of human bodies; and humans being conscious. I suppose the existence of a large physical universe isn’t as strong evidence as the rest, but the other things I regard as extremely powerful evidence. How strong that evidence is depends to some extent on what you think laws of nature are. I wasn’t very clear about what laws of nature are in the first edition of The Existence of God, but I was much clearer in the second edition. I think they are summaries of the powers and liabilities of physical objects. So to say that it is a law of nature that all bodies attract each other in accordance with such and such forces, just is to say, of every chunk of matter in the universe (for example, every atom), that it has exactly the same powers and exactly the same liabilities to exercise them as every other chunk of matter (every other atom). And that is a quite extraordinary coincidence a priori, and it needs a simple explanation. And if you simply say, ‘well, that’s just how it is’, this is just not the way we pursue scientific or historical inquiry. A similar point applies with respect to the other phenomena. A lot of recent attention has rightly been given to the fine-tuning of the universe. That is that the laws of nature each have a constant in them, and that constant has to lie within a very, very tiny interval of all the possible values it could have had, if the universe is to contain life. But that underestimates the force of the total evidence, because it already assumes that there are laws of nature and that they are simple ones. But if you drop any of the laws of nature – for example, suppose there isn’t a gravitational force or suppose there isn’t a strong force – then we could not exist. So the total evidence from the operation of laws of nature is far stronger than evidence of the fine-tuning of the constants. As for human consciousness, if we were to explain that, it would need a very large number of laws, each connecting brain events with mental events, and that too is part of the total evidence of which we ought to take account.

An objection that someone might have is that these arguments looks like they rest quite heavily on what might be called an Aristotelian understanding of laws of nature, on which the laws of nature are true in virtue of the causal powers of objects in the world. How much would these arguments be weakened if one were to adopt a Humean account of laws of nature, on which laws of nature are merely descriptive generalizations about what does in fact happen all the time?

I should say first that the Humean account of laws of nature has rather gone out of fashion in recent years. But if one did adopt such an account, then what one is saying of the laws of nature is that it is just a brute fact that events follow each other in the ways they do. And, once again, if you’re to explain anything – and even Hume wanted to explain things – you have to bring in the criteria for a probably true explanation. You might say that if there are laws of nature, and if they’re just generalisations about what happens, as Hume thought, we use the criterion of simplicity (and so generalise from simple descriptions of phenomena) because it is easier to handle simple generalisations than complex generalisations. But there are trillions of generalisations which will take account of just the same (so far observed) phenomena, but make different predictions for the future. If our preference for simple generalisations were just a conventional preference for what is easiest to handle, then there would be nothing wrong in being guided by any prediction whatever made by any generalisation compatible with evidence observed so far; and so nothing wrong with relying on a theory which is compatible with existing phenomena but predicts that the sun will not rise tomorrow; and that is crazy. We rely on the predictions of the simplest theories compatible with the phenomena, because we believe that it is more probable that simpler theories and so their predictions are true, than that complicated theories and their predictions are true. The Humean cannot explain why we go for the simplest.

Let’s turn to a slightly different concern some might have about your emphasis on the importance of this project of probabilistic natural theology. The worry might be that the ordinary religious believer in the pew typically doesn’t have the time and training to study these sorts of arguments. And so it might look as though on your view, vastly many religious people are in a subpar epistemic position. Does your view have that consequence?

No, indeed not. I think there are two basic principles of rationality before we ever come to my probabilistic arguments for God. The first is what I’ve called the principle of credulity. That is to say: if it seems to you that p, then probably p, unless you have counter-evidence. If it seems to me that there’s a guest in my home and nobody can produce any counter-evidence, then it’s probable on the evidence that there is a guest in my house and so rational for me to believe there is a guest. The principle applies too when the proposition at issue is that there is a God. If there are people who have strong religious experiences apparently of the presence of God, they are rational to believe that they are in the presence of God, unless they have counter-evidence. I don’t think many people have very strong religious experiences; but still, any religious experience is to be taken seriously in the absence of counter-evidence. The other principle, the principle of testimony, is that we should always believe what people tell us in the absence of counter-evidence. Counter-evidence may include evidence that our informants are not qualified to tell us about what they are telling us, or evidence that in fact what they are telling us is false. Almost everything which almost all of us believe about history and geography we haven’t found out for ourselves; we depend on what people tell us. And if the only source of your information is the local priest, or someone you trust, such as your parents, and they tell you that there is a God, then it’s rational to believe them, in the absence of counter-evidence. Quite a lot of people in the Middle Ages were in just that position. In the modern world, people can’t avoid the counter-evidence – counter-evidence in the form, frequently, of learned people who say there is no God; and also of the enormous amount of suffering in the world. And in that case, there is a need for arguments to defeat these counter-arguments. I think there’s a need for arguments a lot more in the modern world than there has been at any time since the fourth and fifth centuries. Those centuries were, I think, times in the Western world where all sorts of beliefs were in competition. But until fairly recently in many countries, Christianity or Islam was the orthodoxy, and these religions claim that there is a God. But in the modern world most people are aware of objections to the existence of God, and objections need to be faced, and that means arguments. Now, arguments, both for and against God, can be given at many different levels. And people must deal with the arguments. I think everybody has some obligation to look at them. There are very simple arguments for the existence of God. My argument from the laws of nature is something that almost everybody could understand. That’s enough to stifle objections at stage one. Many people don’t need to go further. Other people do, but there are many simple expositions of slightly more complicated arguments for God’s existence. And, of course, I’ve tried to write one or two very simple books, trying to produce such expositions. But even if these books are a bit more complicated than I suppose, the simple version of the argument from laws of nature which I have just provided is surely fairly intelligible to a considerable number of non-philosophers.

Regarding the idea that we can treat God as an explanatory hypothesis, a concern that I’m aware some theologians have is that it’s almost as though we’re treating God as we would a hypothetical subatomic particle. The concern seems to be that if we relate to God in that way, then we fail to have a properly reverential attitude towards God. Some theologians might even go so far as to say that this activity that we’re engaged in is a form of idolatry. What would you say to that?

These theologians are recommending that we take the leap of faith without any argument. The trouble is, you can take the leap of faith in any direction whatsoever. What we want to know is why in this direction? And in order to know why in this direction, you need to have some reason to suppose that this is the right direction, that there is a God. Of course, if you’re already convinced of that and you don’t know of any counter-arguments, then fair enough. But if you do know of arguments against the existence of God, it seems to be irrational to take the leap of faith to theism, and especially Christian theism, rather than one in a different direction, and it’s also dismissive of the fact that God has given us reason. Reason is one of the great things that makes humans different from the animals; and the leap-of-faith approach seems to be ignoring this great gift.

Obviously, the problem of evil is one of the major objections to theism. Could you summarise the contours of your response to the problem?

Yes. I have developed my views on this quite a bit over time. You’ll find my latest views in the dialogue between myself and James Sterba, Could a good God permit so much suffering?, which has just been published. What I’m going to say to you is mostly in my contribution to that book. I start from the fact that our major human benefactors, who are our parents and the state, are generally thought to have a right to impose suffering on us under certain conditions. Parents have the right to send their children to a neighbourhood school, even though the children don’t like it, in order to cement relations in the neighbourhood. Why do the parents and the state have these rights? It’s because they are our major human benefactors. Parents brought us into life, and – I’m talking about nurturing parents, not mere biological parents – they have spent a lot of their time and money bringing us up. As a result they have a right to expect certain things from us, in effect to take back some of the good things that they have given us. But they do not have the right to take away more than they have given to us, and so any suffering they impose must leave them on balance still our benefactors. As for the state, without it we’d be living in a Wild West; we’d have no security. And for that reason, states too have a similar right. God is our benefactor so much more than are the state or our parents, because God is responsible for the state having the powers it has and for our parents having the powers they have. God is responsible for the laws of nature. And, above all, God is responsible for our own existence. Although parents may choose to have a child, they don’t choose to have a particular child; God chooses which child they get. So, God is enormously more our benefactor than they are. And, therefore, God has a right to impose far greater suffering on us than do parents and the state. But, of course, there is also a further condition on the right of benefactors to impose suffering. I think it will be generally recognised that parents and the state have the right to impose suffering only if it is necessary for a good purpose – for the good either of the sufferer or of someone else. And those are my two conditions. Someone has the right to cause someone else to suffer if and only if the former remains overall a benefactor, despite the suffering he causes, and imposing the suffering is necessary to provide an (at least equal) good for the sufferer or someone else. I suggest that these conditions apply also to God. But for God, who can do all things that are logically possible, the second condition has the consequence that it must be logically necessary that he cannot provide these good things without imposing the suffering. So, my two conditions for God’s having the right to impose the suffering are that he is and remains our benefactor, and that his imposing the suffering is logically necessary for some (at least equal) good for the sufferer or for someone else. The ‘or someone else’ is rather important. The state has the right to impose suffering on someone for the benefit of someone else. The example I always give is the right of the state to conscript us into the army. That is putting us in danger of death. It’s not good for the person who is conscripted, but it is good for the rest of the population. And, therefore, God has the right to impose on us much greater suffering, for the sake of a good which it is not logically possible for him to give to anyone else without imposing that suffering on us.

In general, I suggest, God satisfies the first condition because, despite the amount we suffer, our earthly life is on balance such that it is good to have lived it. But for any humans whose earthly life is not on balance such that it is good for them to have lived it, God can always give us a longer life after death in which our happiness outweighs that earthly suffering; and, in virtue of his perfect goodness, he will surely do this. But it needs to be shown that God always satisfies the second condition, that allowing us to suffer is always for the benefit of ourselves or others. The first obvious point to make is that it’s a great good to us if we have libertarian free will, of a kind that allows us to cause either good or bad effects. A separate argument is required for the claim that we do have libertarian free will. But on the assumption we do have libertarian free will, it’s an enormously great good for us that we are, as I sometimes put it, mini-creators. We can make a difference to the world, make a difference to other people, and make a difference to ourselves. That’s an enormous good for us. But for us to have free will of that kind, God must not interfere with our choices. And that has the consequence that the evil humans do to others is not prevented by God. But, of course, there are evils which are not caused by other humans. These are ‘natural evils’, the evils of disease and earthquakes and such like. So what’s the point of those? The point of those is to give us the opportunity to deal with them. If we were all made so that any harm we did was the result of pure malevolence, we’d be pretty nasty people. But we can also do harm by the lesser evil of simply neglecting to prevent some natural evil occurring. And this gives us many opportunities that we would not otherwise have. For example, if I get ill, that gives other people the opportunity to help me, by getting me medical help, looking after me, and being sympathetic to me. But it also gives me the opportunity to cope with my illness, by being patient and not becoming sorry for myself or bitter because others do not look after me sufficiently; and so on. And in both of these ways, by making good choices, we not only produce the desired effect, but also we change our own characters. Each time we make a good choice of a certain kind, it becomes easier to make good choices of that kind in future. Conversely, each time we make a bad choice of a certain kind, it becomes harder to make good choices of that kind in future. So, we have the opportunity to form our own characters, either for good or bad. These two are the basic reasons why God allows moral and natural evils – to allow us to make differences to the world and each other, and thereby form our own characters.

You might feel that this works for lesser evils. But why some of the horrendous things humans do to each other? It’s important to bear in mind that these horrendous evils are fairly short-lived in the scale of eternity. And if we suffer for a long time, it would have to be limited suffering if we are not to die quickly from it. But, of course, horrendous suffering remains horrendous. However, it gives us the opportunity not merely to make ourselves quite good people, but to make ourselves saints, which otherwise we wouldn’t have the opportunity to do. It also gives people the choice to make themselves very evil people. I don’t think anybody would be happy in heaven unless they were a saint. A saint is someone who wants to spend their life helping other people and glorifying the all-good source of good things, which is what early Christian theologians claimed were the occupations of the occupants of Heaven. Ordinary good people might not want to do that everlastingly. But I think that God is ambitious for us. He doesn’t want us to be mere ordinary good people, as a sideline, as it were. His plan for us is for us to become saints. And at the other end, I think everyone should have the opportunity to reject God. The analogous example I always give is that of the suitor. The suitor asks the beloved for her hand in marriage and gets the answer ‘no’ first time. He’s entitled to ask again. He’s perhaps entitled to ask many times. But he’s not entitled to go on asking for ever. To do so would be to regard the beloved as not having the right to choose her own future for herself. For the same reason, in the end God must take ‘no’ for an answer and allow people to become the evil people they have chosen to be. But no one (except those who are psychopaths from birth, and what I am saying doesn’t apply to them) makes very evil choices at the beginning of their life. Rather, they make themselves evil people by making worse and worse choices, until finally they simply lose the concept of an action being morally good. But they can only do that by bringing about a horrendous evil without the slightest regret. God surely gives people many choices. If there’s a spark of goodness left in them, there remains the possibility that they will make the right choices; and so put themselves back on the road to sanctity. But if people are to have the ultimate choice of what sort of a person they are to be, they need to have the possibility of causing horrendous evils and in no way regretting doing so.

I wonder how animal pain gets covered by your account. As you said, on your account God can allow us to undergo suffering for basically two reasons: it benefits us; it benefits someone else. One might think that with animals, their sufferings are going to be rather heavily on the benefitting-someone-else side of things. You also said that an important part of the purpose of this moral arena God has constructed is that he wants us to be able to choose to become saints. But it doesn’t look like animals get that choice.

I don’t think animals have libertarian free will. I also think that they don’t suffer as much as we do. We suffer a lot, and I think that single-celled organisms don’t suffer at all. The question is: which animals do suffer? The mere fact that an animal reacts to a bodily injury is in itself no evidence that they are suffering. You can’t argue from same effect (moving away from the cause of the injury by both humans and animals) to same cause (feeling pain). But you can argue from same cause to same effect. In humans there are two neural channels from a bodily injury, one of which leads to our public reactions, and the other of which leads to our pains. And it’s possible to block off either of these channels. So, in order to have good reason to believe that certain kinds of animals suffer it needs to be shown that those animals have a part of their brains corresponding to the part of our brains which cause our suffering. My view is that it follows that we have no good reason to believe that any animals suffer except the mammals, and possibly the birds. The part in their brains which correspond to the part in our brains which underlies our suffering is either somewhat different from ours or comparatively smaller than ours. For example, in the brain of our nearest relative, the chimpanzee, the part that is responsible for pain is three times smaller than ours, and that gives reason to believe that, although they suffer, they do not suffer nearly as much as we do. So, to generalize, I conclude that only some animals suffer; and the ones who do, probably don’t suffer as much as we do. Now, it’s also a benefit for humans, not merely if we do something good voluntarily, but also if we do something good involuntarily, which we are compelled to do. It’s a benefit for prisoners if they are made to clean the sewers rather than just break up a rock which nobody is going to use. They are contributing to society, and they value that. Prisoners often say that what they value most is being able to help other people in some way. It is a benefit for one person if they are of use to other people. People can also be of use if they suffer in some way or are even killed as a result of a bad accident, if that accident leads to some reform which prevents such things in future. I grant that these are not benefits nearly as great in any way as the benefit to us of doing good things of our own free will. They are benefits, nevertheless. And, so, I think that animal suffering is less than ours – significantly less than ours – but also does have these benefits for the animals, because animals do things which are extremely good things to do: in particular, saving their own lives and getting food for their offspring. An example I always use is of a mother bird who acts as a decoy to prevent a predator killing her offspring. That’s a great benefit for the mother (as well as for her offspring). One must always ask oneself in this case: what sort of a world would God want? Would God want a world where all animals live in zoos? Or would God want one where they live in the wild, where they have risks they try to avoid, where they have tasks that are worth doing, and so on? That would be the general outline of my argument. But it does depend on my view about which animals suffer and how much they suffer; and it is possible – though, I suspect, unlikely (since animals cannot talk) – that neuroscientists may make some new discovery relevant to this issue.

A final question on the problem of evil: as I’m sure you know, the Wittgensteinian philosopher of religion D.Z. Phillips offered some quite strident moral criticisms of your approach to the problem of evil, and particularly of your notion of being of use to others. He wrote that ‘to ask what use are the screams of the innocent, as Swinburne’s defence would have us do, is to embark on a speculation we should not even contemplate’. How would you respond to that sort of moral critique of your approach?

It’s a natural reaction for a convinced atheist to whom it seems so ‘obvious’ that suffering serves no good purpose, that there’s no point in offering a theodicy. In this respect a Wittgensteinian ‘theist’ is in just the same position as an atheist. Phillips didn’t believe that there’s a God. So given that, his situation is understandable. But for someone who has come to think there are good reasons for believing there’s a God, there’s an objection to be faced in the form of the problem of evil. And it’s reasonable in those circumstances to face up to the objection and see whether a theodicy works.

You’ve offered natural theological arguments not just for bare theism, but also for the central claims of Christianity. Could you summarise your argument for thinking that Jesus of Nazareth is probably God incarnate who was raised from the dead?

If you’re investigating any claim that a certain historical event occurred, there are always two sorts of evidence you ought to take into account. First, there is the evidence which is more likely to be discovered if the event occurred than if it did not occur. When, for example, it is claimed that King Richard III arranged the murder of the princes in the Tower of London, any record of what some contemporary witness wrote or any physical evidence subsequently discovered, has to be taken into account. Suppose we have evidence that some contemporary writer, whom there is no reason to suspect of bias, wrote that Richard arranged the murder. It is much more probable that that evidence would have been found if Richard had arranged the murder than if he had not arranged the murder. Hence, it constitutes evidence that Richard did arrange the murder. But, secondly, you need to take into account evidence from a wider field about whether the event is a kind of event likely to have occurred; and so, in my example, evidence about whether Richard was or was not likely to commit such a murder. I call this ‘background evidence’. If we have evidence that he was the sort of person who would arrange a murder to forward his ambitions, that would make the claim that he did arrange this murder more probable; and if we have evidence that he was not that sort of person, that would make the claim much less probable. Applying this model to the claim that Jesus is God incarnate who rose from the dead, let’s look first at the second kind of evidence, the ‘background evidence’, about whether it is probable that there is a God who would become incarnate in that sort of way. Given that, as I have argued, probably there is a God who is perfectly good, we must consider whether such a God is likely to become incarnate and do and suffer the kind of things which Jesus did and suffered. There are three reasons why God is likely to become incarnate and do and suffer those kinds of things. The first reason is to identify with our suffering. God makes us suffer a lot. We’ve talked about why he makes us suffer. Suppose there’s a law that says that 18-year-olds have to be conscripted into the army unless their parents object, and suppose I have an 18-year-old who is about to be conscripted. He asks me to object and I say, ‘No, it would be good for you to fight in the army’. But if I am able-bodied and able to volunteer, it would be good if I also joined the army. That would show solidarity with my son and would provide a justification for me allowing him to be conscripted. Analogously God might be expected to suffer the kinds of things that we suffer in order to identify with our suffering. The second reason, which is the reason for an incarnation more normally put forward in Christian tradition, is that humans need atonement for our sins, we are unable to provide it ourselves, and so a perfectly good and so loving God might become incarnate for this reason. I suggest that if God came to earth as a human, lived a perfect life, getting killed for so doing, that would provide the required atonement. And the third good reason is to give us an example of how to live. However carefully moral rules are stated in writing, we understand much better what it is to conform to them if we’ve got a concrete example of someone who lives by them. So, there are these three reasons why God might become incarnate as a human.

If God did come to earth as a human, how would he have to live in order to fulfil these reasons for his incarnation? He would need to show that he believed himself to be God and that he was offering his life as an atonement for human sins, he would need to live a perfect life in which he endured much severe suffering of the kind that some humans endure, to found a church to continue his work, and have that life culminated by an event of a kind which God alone could do to provide God’s signature on his work. I believe that the evidence supports the claim that Jesus of Nazareth fulfilled all these requirements. He didn’t go around saying, ‘I am God’. If he had done so, the obvious interpretation would be that he was claiming to be the sort of god whom pagan religions claimed sometimes temporarily became incarnate, and the Jewish population would have concluded that such a person could not be the God whom they worshipped. Hence, it is not to be expected that Jesus would Jesus go around saying he is God incarnate before he has been crucified and shown what God’s incarnation means. But he would need to leave behind enough signs so that after the event, people could realise that he was claiming to be God incarnate. And Jesus did that. The first sign he left behind is that he claimed to forgive sins, which – Jews believed – God alone could do. The second sign is that his actions led to his trial at which the accusation against him was ‘blasphemy’, meaning that he had been claiming the prerogatives of God. And the third sign was that, after his crucifixion and purported resurrection, he allowed himself to be worshipped – both Matthew’s and John’s gospels claim that the apostles worshipped Jesus then; and, Jews believed, God alone deserves worship. In claiming that he was replacing the Temple, Jesus was claiming that he was providing the means of atonement that the Jews, perhaps mistakenly, believed that the Temple provided. Insofar as we know the details of his life he certainly did live a perfect life, ending with being crucified and thereby suffering one of the worst evils that humans suffer. The fact that he appointed twelve apostles indicated that he was founding a new community, a church, to make the news of his incarnation and its consequences available to everyone, everywhere, replacing the old Israel, based on the twelve sons of Jacob, after whom the twelve tribes of Israel were named. And, I believe, the evidence shows that after three days he rose from the dead, which, being a ‘violation’ of laws of nature, is an act which God alone can do; and so God put his signature on the work of Jesus. So Jesus fulfilled very well the requirements for God becoming incarnate for the sort of reasons which, I claimed, we would expect a perfectly good God to become incarnate. But there is no known other human who satisfied even most of these requirements. Neither Mohammad nor the Buddha claimed to be God incarnate, or to make atonement for human sins; and although some modern gurus have claimed to be God incarnate, their lives have not been perfect or culminated by great suffering, nor is there evidence of God’s signature on their actions. I conclude that the background evidence suggests that we might expect God to become incarnate in the way in which Jesus became incarnate, and no other human – to our knowledge – has lived a life of that sort. All of this together gives significant probability to the claim that Jesus was God incarnate.

A concern someone might have is that this case for Christian theism relies on a number of claims about what God would do – that God would be likely to become incarnate in order to make atonement, establish a church, provide moral teaching, and so on. The worry might be that we shouldn’t really have much confidence in the intuitions upon which these claims are based.

We get our intuitions about what a perfectly good creator would do by reflecting on how good parents would behave towards their children. Good parents make atonement. They pay the fine that the court imposes on their children. Parents share the suffering of their children. Parents seek to be real examples to their children. God is much more our creator than our human parents, and also perfectly good. So, taking account of the difference between human parents and God in respect of power and goodness, we can reach a conclusion about how (probably) God would behave towards us.

Since the 1990s, as I understand it, you have found your spiritual home in the Eastern Orthodox branch of Christianity. Would you say there are any aspects of your work that have been shaped by distinctively Eastern Orthodox ways of thinking?

No, I don’t think there have been. I don’t think there are any serious differences between the central doctrines of Orthodoxy and those of other large Christian ‘churches’. I don’t believe in the extra bits that the Roman Catholic Church added, such as papal infallibility. But I share the Orthodox critical view of some other Christian ‘churches’, that they have tended not to stop their priests teaching doctrines incompatible with those central doctrines, and have tended to be too ready to abandon important parts of Christian moral teaching (for example, about sexual matters). But I didn’t join the Orthodox Church because I thought they had doctrines that other Christians didn’t have.

Your approach to the Trinity is what some people might describe as a more social Trinitarian model. So, I wonder whether it’s more than coincidence that your model has some affinities with the Cappadocian approach to the Trinity?

I cannot recall what led to my formulating my version of the social theory of the Trinity, but I knew what Gregory of Nyssa thought about the Trinity. Above all, I knew what Richard of St Victor thought about the Trinity and, of course, he was Roman Catholic. I think that when it is said that the social Trinitarian view is an Eastern view, and that monist Trinitarianism – if that’s the correct description of the view that the Trinity is one substance – is a Western view, my view is that the monist view is a novelty. If you go back to what Aquinas and Scotus wrote about the Trinity, as well as above all what Richard of St Victor wrote about the Trinity, you’re a lot nearer to the social Trinitarian model than you are to monist trinitarianism.

Over the years it seems as though you’ve had a lot of opportunities to travel in Eastern Europe and build philosophical partnerships out there. Can you tell us a bit about how that came about?

After leaving school, and before starting my undergraduate studies at Oxford, I had to do my national service. At that time young men were obliged to do two years compulsory National Service. Those ‘called up’ could opt to join the navy, the army, or the air force, and to train for various military jobs. You could opt to become a military engineer or an infantryman or a radio operator or a gunner or one of many different specialists. You weren’t necessarily accepted for your preferred option, but the military would try to satisfy your preference if they thought you were suited for it. Around 1950 it suddenly occurred to the government that at that time hardly anyone could speak the enemy’s language. It was believed that there would soon be a world war against the Soviet Union, and navy, army, and air force all needed Russian interpreters. I joined the Navy and was accepted for the interpreter course. That involved spending almost 20 months of my national service doing nothing else except learning Russian, some of the time in civilian clothes. So, at the end of the course I could speak Russian fairly fluently. But I had no use for it for the next 40 years. However, when the Cold War ended, because of some contacts I had with Russia I gave one or two lectures in Russian in Russia. In about the year 2000 the Society of Christian Philosophers set up an ‘Outreach to Russia’ committee and an ‘Outreach to China’ committee; and they asked me to chair the Outreach to Russia committee. We got a grant from the John Templeton Foundation, which enabled us to run a summer school for Russian philosophers and theologians, have conferences with Russians, and to pay for a programme of translating various philosophy of religion books into Russian. That gave me many more contacts with Russians and more occasions to visit Russia and lecture in Russian. I ceased to be chair of that committee in about 2014, not because I wasn’t enthusiastic about it, but because I think that all committees ought to change their chairs and members from time to time. I have still kept up my connections with Russia. But it has not been possible to visit Russia since Russia invaded Ukraine. I think I have had some success in developing analytic philosophy of religion in Russia – at any rate I’ve helped them to learn about it. And I have done a lot of lecturing (in English) in Eastern Europe generally, not specially arising from my connections with Russia, but arising perhaps partly from my membership of the Orthodox Church.

Latterly, you’ve devoted quite a lot of time to the philosophy of mind. It seems that a fair number of philosophers of mind these days are open to property dualism, the view that mental properties such as the sensation of tasting coffee are distinct from neurophysiological properties having to do with brain states. But you’ve wanted to go further and argue that the mind is a distinct substance from the brain. What would you see as the strongest arguments for making that further step to substance dualism?

I’m careful not to use the word ‘mind’, which seems to be used in various different ways. I use the word ‘soul’, and I use it in Plato’s and Descartes’s sense, as the name of a kind of substance. I argue that each human consists of two parts, a soul and a body, and these are in interaction with each other. I argue that the soul is the essential non-physical part which makes me me, and that there are no logical difficulties in supposing that it could exist without my body. In my book Are We Bodies or Souls? I gave two separate arguments for this. One argument is for our soul being necessary for our existence, and the other argument is for our soul being sufficient for our existence.

In these arguments I define a physical substance and a physical property as ones to which there is public access – anyone can discover the existence of any physical substance or the instantiation of any physical property just as well as can anyone else can. I define a mental substance and a mental property as ones to which only one person has privileged access by experiencing them. Thus, my sensory properties (for example, having a red image) and my occurrent beliefs are such that I can know better than anyone else that they occur, because I experience them. The first argument starts from the fact that the instantiation of our mental properties, that is our conscious life, depends on the operation of our brain and in particular on the cerebral cortex. The cerebral cortex is comprised of two cerebral hemispheres, a left and a right hemisphere. A few people have had a very acute form of epilepsy, which can only be cured by cutting out one of the cerebral hemispheres. Modern neuroscience has made the crucial discovery that if you cut out either of these hemispheres from someone’s brain, it doesn’t make much difference to that person’s memory beliefs and attitudes. So that opens the practical possibility of the well-known thought experiment where a surgeon takes out both my cerebral hemispheres and transplants them into the bodies of two unfortunates who have had both their cerebral cortexes removed, putting my left hemisphere into one of them and my right hemisphere into the other. Given the discovery that only one cerebral hemisphere is needed to preserve someone’s memory beliefs and view of life, since each of my two hemispheres caused me to have similar memory beliefs and a similar overall view of life, it will then follow that both of the subsequent persons would claim to be me. But, of course, they can’t both be me, because they are now having different experiences from one another. They must be different people. So, there are only three remaining possibilities: the one with my left hemisphere is me and the other one isn’t; the one with my right hemisphere is me and the other one isn’t; or neither of them is me. But there is no conceivable scientific experiment which could show which of these is the true account. Hence, we don’t know of each of the subsequent persons whether or not they are me. Now consider one of them. The one with my left hemisphere claims to be me, and yet it’s logically possible that that person isn’t me. So, something else must be necessary for being me other than brain parts which are physical parts, and properties of the brain which are physical properties, and certain mental properties. So, if it’s not a physical part, and it’s not mental or physical properties which make me me (since we know all about these, and yet do not know whether that person is me), the only remaining possibility is that it is a mental part that makes me me. And for that reason, I think it’s necessary that there is a mental part, a soul, that makes all the difference to whether someone is or is not me. That’s the first argument, much condensed.

The second argument is in essence Descartes’s argument for the sufficiency of that mental part for my existence. Descartes’s argument, adjusted a bit, is as follows: I can conceive – which is to say, I can see that it’s logically possible – that I lose my body and yet continue to have a conscious life. How do I know this is conceivable? Well, surely I can imagine it, and, indeed, many people describe having a near-death experience of being out of the body and looking down on the body from above. We may think this a hallucination, and maybe it is. But my point is, we can understand what it is they are hallucinating; we understand, as a coherent claim, what they are saying. We can coherently imagine what it’s like for that to be true, and that’s just that I could lose my body and yet continue to exist. Hence there’s no logical difficulty in the idea of me losing my body and yet continuing exist. But no substance can continue to exist if simultaneously it loses all its parts. So, I must already have had a part, the soul part, if I am to continue to exist while losing my body. And given that, it follows that having a soul is sufficient for me to exist.

A common worry about substance dualism is that it doesn’t take seriously the extent of the correlations that modern neuroscience is uncovering between conscious experience and brain activity. The vast extent of the correlations isn’t something that was really anticipated before the twentieth century. It doesn’t seem viable any longer to think that the mind interacts with the physical body via a single brain region – for example, the pineal gland, as Descartes thought. So, could you sketch how a modern version of substance dualism might envisage the mind-brain relationship in a way that can take seriously these findings?

Yes, there’s no problem about that. Neuroscientists are discovering that we need one part of the brain for having experiences of sound, we need another part for having experiences of vision, we need another part to form intentions, and so on. Thus, we are coming to know which parts of the brain are necessary for which sorts of conscious experience. Taken together, this total extended area is the part of the brain which interacts with the soul. And there are lots and lots of separate interactions between different brain states and different mental events (which are instantiations of mental properties). But there is an issue about whether our mental events are caused entirely by brain events. And it doesn’t look as if they are, because when we go through an exercise of reason – for example, working out the answer to a mathematical problem – what influences the conscious conclusion we reach is our conscious expression to our self of the previous step in the calculation. The physicalist can try to avoid this conclusion by being an epiphenomenalist and claiming that it is an illusion to suppose that one mental event ever causes another mental event. More generally, epiphenomenalism holds that, while brain events cause mental events, mental events never cause other mental events or any brain events. So, an epiphenomenalist would hold that each conscious step in the mathematical calculation is caused solely by a brain event. But epiphenomenalism is self-defeating. For how could you know anything about someone’s past mental life, and so be justified in advocating some theory about what causes it, unless they told you about it? They can only tell you about it if their occurrent memory beliefs cause them to open their lips and provide information. And how are they to remember correctly what happened? The answer must be that what they experienced caused brain events which caused their present memories. So mental events must sometimes cause brain events. So, there is no reason why an earlier conscious expression of the calculation could not cause (if not directly, then via our brain events) our conscious expression of the conclusion. Therefore, epiphenomenalism, the view that mental events never cause brain events or other mental events, is self-defeating. If it is true, we could not have any evidence that it is true.

Over the past few decades, you’ve taken up invitations to speak to wider audiences, you’ve done some public debates, and you’ve even turned some of your academic books into popular level books. How did that interest in addressing a wider audience arise?

It’s because I think the wider audience wants to know the answers to the questions which I discuss, such as whether God exists, and whether each of us has a soul which makes us who we are. It’s as simple as that. And I do take opportunities to address larger audiences for just the same reason, with the hope that my talks might lead to them reading the books. And I’ve done quite a bit of popular presentation of my ideas recently in Zoom podcasts, which is a way of reaching large audiences without travelling anywhere.

Do you think this is something that philosophers more generally should be trying to do with their work?

If they think their work has implications for how people ought to live, certainly. And they should do so even if their work does not have those implications, but merely because non-philosophers are interested in the answers to (most of) the questions which philosophers discuss, because they are big questions about the foundations which sustain our existence and the existence of the universe, and about the nature and knowability of apparent moral truths.