Like a lion, perhaps, in a den of Daniels, I gave a talk last week on ‘Why I am an atheist’ to theology students at Bristol’s Trinity College. It was an enjoyable event, and hopefully helped me to think through and sharpen my arguments (though not, I suspect, to change anyone’s mind). Here’s the transcript.

There are three kinds of arguments that an atheist can make in defence of the insistence that no God exists. First, he or she can argue against the necessity for God. That is, an argument against the claim that God is necessary to explain both the material reality of the world and the values by which we live. Second, he or she can argue against the possibility of God, against the idea that a being such as God is either logically or materially possible. And third, an atheist can argue against the consequences of belief in God. This is the claim that religious belief has pernicious social, political or moral consequences and that the world would be better off without such belief.

Historically, much of the discussion of God has been about the possibility of God. Christian apologetics grew out of the attempt rationally to defend the possibility of God’s existence, while atheists wanted to show that the idea of God made no rational sense. Much of the contemporary debate is about the consequences of religious belief. The so-called New Atheists, in particular, have been scathing in their attack on what they see as the wicked and malevolent social consequences of faith – from the harassment of gays to mass suicide bombings. I, too, am sceptical of the possibilities of God. And, while I do not think, as many do, that faith is, in and of itself, pernicious, I do believe that there are often social and moral problems that arise from religious belief. What I want to concentrate on today, however, is on the first type of argument. And that is because for me, as it is for many other atheists, this is the primary motivation for my atheism – I simply do not see the necessity for God.

There are three kinds of reasons often given for the necessity of God. First, there is the claim that God is necessary to explain Creation and the maintenance of the cosmos. Second, that God is a necessary source of moral values; that without God we would fall into the abyss of moral nihilism. And third, that without belief in God, there can be no purpose or meaning to life. Let us look at each of these claims in turn.

The Christian idea that God is necessary for the creation and maintenance of the universe can be traced back to pre-Christian, pagan philosophy, to the Greek tradition, and in particular to Aristotle. Aristotle argued for the existence of a First Cause or Uncaused Cause to the universe. The universe, Aristotle argued, is forever in a state of flux. Behind every change must lie a cause, and indeed a chain of causes, that brings about that change. But such a chain of causes cannot stretch out for ever because it is impossible to have an infinite regress of causes. The first link in the chain, as it were, was what Aristotle called he Unmoved Mover, the prime cause of all change in the cosmos, but which itself was not caused by anything. This Unmoved Mover Aristotle called ‘god’, not as an entity to be worshiped, but as ‘a supreme and eternal living being’, the most powerful, intelligent and beneficent creative force in the cosmos.

This argument, which came into the Christian tradition via the Kalam school of Muslim philosophy, lies at heart of the first three of Thomas Aquinas’ famous ‘Five Ways’ of proving the existence of God. It is often called the cosmological argument, though strictly speaking this refers only to Aquinas’ third proof, which was so labelled by Kant. The cosmological argument is of this general form:

1 Whatever begins to exist has a cause

2 The universe began to exist

3 Therefore it has a cause

There are many variations of this general argument. For instance, what is often called the contingency argument, states that

1 Whatever exists must have a cause

2 The universe exists

3 Therefore the universe must have a cause

All variants of the cosmological argument comprise three basic elements. First, the claim that there cannot be an infinite regress of causes, so there must be a First Cause. Second, the insistence that any such First Cause must lie outside of time and space because it is itself the creator of time and space and a creator cannot exist within that which it has created. And, third, the assertion that the only being that can lie outside time and space is God. Hence, the argument runs, God is a necessity for the creation and maintenance of the universe. The problems with this argument have long been recognized, including by Christian theologians themselves. I will mention just four.

First, why insist that one cannot have an infinite regress of causes? William Lane Craig, perhaps the most cogent of contemporary defenders of the cosmological argument, suggests that the idea that one cannot have an infinite regress of causes ‘is so intuitively obvious that I think scarcely anyone would sincerely believe it to be false.’ Intuitions may be important in all manner of ways, but they do not necessarily make a good premise for rational argument nor the basis for evidentiary claims about the universe. After all, it seems intuitive that the sun revolves around the Earth, which is why the heliocentric view of the solar system took so long to accept. It does not seem intuitive to think of light as being both waves and particles, and yet physicists today think of light as possessing properties of both. And so on. In any case why should the idea of an uncaused First Cause seem any more intuitive or coherent or believable than the idea of an infinite regress of causes?

A second problem is the question of what caused the First Cause. Of course, the very concept of the First Cause is that it is uncaused. But that is simply to say, if we believe that there cannot be an infinite regress of causes, then we must accept that there must be some beginning to the chain of causes. But that simply leads back to the question of why there cannot be an infinite regress of causes.

If it is possible for God to exist without a cause greater than God, why is it not possible for the universe to exist without a cause greater than itself? It won’t do to answer, ‘Because God is of the form that requires no cause greater than itself’. We do not know what it is to be of a form that requires no cause greater than itself. Therefore the universe could equally be thought of as a form that requires no cause greater than itself.

Indeed the very concept of an infinite regress of causes is simply another way of saying that the universe is of a form that requires no cause greater than itself. In this sense the concept of the ‘Uncaused First Cause’ and that of an ‘Infinite regress of causes’ refer to the same phenomenon – our ignorance about the origins of the universe. Accepting an infinite regress of causes is simply to make explicit that ignorance; the idea of the Uncaused First Cause is philosophical handwaving to cover our ignorance and imagine that we actually have an answer.

Third, why should the First Cause be God? The argument is that the First Cause necessarily lies outside time and space since, in creating the universe, it also created space and time. And any being outside time and space must be God. The trouble is that God, or at least the God of theists, possesses many properties that are not implied simply by First Cause. He is supposed to omniscient, omnipotent, benevolent, loving, forgiving, and so. So, even if we accept the idea of an Uncaused First Cause, there is no reason to see that Cause as God, certainly as theists understand it.

And this leads us to the fourth problem. Aquinas defined the God outside space and time as a wholly simple God, a God without parts, without body, a God who is immutable, unchangeable, necessary. A God beyond human understanding or imagination. But, of course, this is not the God of Scripture. The God of Scripture is not outside of space and time, but actively intervenes in both space and time, and, in the Christian tradition at least, is immanent as well as transcendent. How could a wholly simple God outside of time and space act upon time and space?

This tension between Aquinas’ wholly simple God and the God of Scripture has been at the heart of much theological debate. Aquinas himself suggested that God may act timelessly to bring about an effect within time. Even the sympathetic theologian Peter Vardy says of this, that ‘It is, admittedly, hard to understand what a timeless action involves’. But, he adds, ‘If God is beyond time and space, then God is largely mysterious to those within time and space. If the existence of God is accepted, then the possibility of God acting timelessly to produce a temporal effect is not impossible.’ But this, it seems to me, is little more than saying that since God is beyond our comprehension, then there is nothing wrong with imagining God doing impossible things. Or, to put it another way, that since there are many things of which we are ignorant, so let us accept that impossible things are possible. That may not be an irrational sentiment, but it is not a particularly useful one either. Nor is it an argument for the necessity of God. Similar questions and criticisms can be made, and have been made, about other theological proofs for the necessity of God’s existence, such as the proof from teleology or the ontological proof.

In a sense, though, all these questions and criticisms are immaterial. No one comes to believe in God because they have been convinced by the arguments for God’s existence. No one says, ‘I was unsure whether God existed, but now I have read Aquinas’ first three proofs, I am convinced that He does.’ Rather they insist, as philosopher Peter Stannard does, that ‘I don’t have to believe in God, I know that God exists – that is how I feel.’

The proofs, therefore, are a means of demonstrating not the existence of God but the intellectual soundness of belief in God, of demonstrating that such knowingness can be rational. If you already believe in God, these proofs suggest that such belief may not be irrational. But if you do not already believe in God, they certainly do not demonstrate the necessity for doing so.

The difference between believers and atheists is not about whether either can explain the ultimate cause of the universe. It is about how we wish to explain it. I am happy to say, ‘I do not know what First Cause is, or even if there is one. It may be that one day we discover the answer to that. Or it may be that we never will. For now I am happy to keep an open mind, accept our ignorance of First Cause and live with the uncertainty of not having one’. Believers are unwilling to say that. They insist that there must be a First Cause and that that First Cause must take the form of God. They cannot live with the uncertainty about First Cause that comes with non-belief. In Peter Stannard’s words they know – they have to know – that God exists. The difference between believers and atheists is, in other words, not simply a difference of philosophy, it is also a difference of psychological temper.

A similar distinction can be drawn between atheists and believers with respect to the second issue for which it is claimed that God is necessary – morality. ‘If God does not exist, everything is permitted.’ Dostoevsky never actually wrote that line, though so often is it attributed to him that he may as well have. It has become the almost reflexive response of believers when faced with an argument for a godless world. Without religious faith, runs the argument, we cannot anchor our moral truths or truly know right from wrong. Without belief in God we will be lost in a miasma of moral nihilism. ‘The elimination of God’, the theologian Alister McGrath writes, ‘led to new heights of moral brutality’. Though given the extent of brutality undertaken in the name of God, I am not sure that that is a particularly astute sentiment.

‘If God does not exist’, William Craig claims, ‘Objective moral values and duties do not exist’. There is a voluminous philosophical literature on the debate between moral realists and moral anti-realists, that is between those who see moral values as akin to facts, and those who reject that idea. It is an intellectual swamp, and one into which I do not intend stepping, at least in this talk. All I would say is it is possible to believe that moral questions have non-arbitrary answers without conflating facts and values. But that is for another discussion.

What is striking, though, is that, contrary to what is claimed in this kind of theological assault on atheism, many of those most hostile to religion are also the ones who insist that moral statements are in fact objective facts about the world. The philosopher Patricia Churchland argues that it is a ‘false dilemma’ to claim that ‘either God secures the moral law or morality is an illusion’ because ‘Morality is grounded in our biology’. Sam Harris, one of the so-called New Atheists, and perhaps the most strident of contemporary critics of faith, in his book The Moral Landscape, attacks both religion and moral relativism, arguing that moral values are in reality moral facts and as facts they can be scientifically understood by studying brain and behaviour. ‘The wellbeing of humans and animals must depend on states of the world and on states of their brains’, he writes, ‘and science represents our most systematic means of understanding these states’. Science, and neuroscience, do not simply explain why we might respond in particular ways to equality or to torture but also whether equality is a good, and torture morally acceptable. A Christian might look to the Bible to help distinguish right and wrong, good and evil. Harris would look in an fMRI scanner.

I am highly critical of Harris’ views, often for many of the same reasons that I am critical of theological claims about morality. This is no place to enter into that debate. All I want to show is that the claim that atheists do not believe in ‘objective moral values and duties’ is not true. Let me concentrate here on why God is not necessary for instantiating moral values.There are three broad reasons for challenging the idea that God is necessary for a moral life.

First, because moral values do not have to be defined by God to be non-arbitrary. Briefly, I see three primary sources of human values: empathy, reason and community. As humans we have a sense of empathy with others, partly natural, partly culturally given. Reason allows us to take that sense of empathy and transform it into a thought-out moral framework. And that framework is shaped not just by a sense of empathy but by the needs both of the collectives in which humans are embedded and by the history of which they are a product. All of which is why moral frameworks are both contingent and non-arbitrary. Contingent, because as human creations, values are not absolutely fixed in stone. Non-arbitrary, because empathy, reason and community all impose a framework, all impose constraints and boundaries upon our moral universe.

Second, most of the moral claims made by Christianity are to be found in other ethical systems, both religious and non-religious. Take, for instance, the Sermon on the Mount, perhaps the most influential of all Christian ethical discourses. The moral landscape that Jesus sketched out in the sermon was already familiar. The extensions of the Mosaic law upon which Jesus insisted were already part of the Jewish tradition.The Golden Rule – ‘do unto others as you would have them do unto you’ – is central to many religious traditions, as well as to many non-religious ethical systems, from Confuscianism to Kantianism. The insistence on virtue as a good in itself, the resolve to turn the other cheek, the call to look inwards, the claim that correct belief is at least as important as virtuous action – all were important themes in Greek Stoic philosophy. Similarly, the concept of universalism, often seen as a key Christian ideal, was also drawn from Stoicism. Neither God in general, nor the Christian God in particular, is necessary, in other words, to derive such values.

Third, believers and non-believers face exactly the same problem when it comes to moral values. Believers often claim that without God every human has to make up his or her own mind about what is right and wrong. There is no anchor for moral values. Rather everyone can pick and choose as to which values they accept and which they reject. All of which is true. But all of which also applies to believers. For pick and choose is exactly what believers do.

Leviticus sanctifies slavery. It also tells us that If a ‘man commiteth adultery’, then both ‘the adulterer and the adulteress shall surely be put to death.’ And it instructs believers to ‘chase your enemies and they shall fall before you by the sword.’ According to Exodus, ‘thou shalt not suffer a witch to live’. It also insists that those who work on the Sabbath may be put to death. Genesis implies that birth control is a capital offence. Proverbs tells us to ‘beat the child with the rod’. And so on. Few modern day Christians would accept such commands. But other commands they would accept. You might say, ‘Of course that would be case. After all, the Bible was written 2000 years in a very different world facing very different problems, and with very different social and moral resources.’ And that’s exactly my point. As societies change so do moral values. So Christians come to interpret the Bible differently. But ‘interpreting the Bible differently’ means deciding for ourselves which values make sense and which no longer do.

Let us not forget that in the past, thousands of witches were burnt and millions of people enslaved, because it was believed that God had sanctified such practices. In the past such Biblical values were acceptable. Today they are mostly not. That change has come about not because God has changed His mind but because humans have. Even today, some Christians, reading passages in Leviticus and in Paul, think that the Bible justifies the execution of gays. Others, reading the Bible differently, insist that practising homosexuals are committing no sin at all. Each reads the Bible as they wish to fit into their own moral framework. Belief in God, in other words, does not obviate the need for each of us to make up our minds about what is right and what is wrong. Even those who read the Bible (or the Qur’an) literally have chosen to follow a particular set of values.

The fundamental problem of looking to God to define right and wrong was expressed 2000 years ago by Plato in the so-called Euthyphro dilemma. In his dialogue Euthyphro, Plato sets up a discussion between Socrates and Euthyphro, who is about to prosecute his father for the murder of one of his servants. Socrates is shocked by Euthyphro’s action, which appears to disregard both convention and his obligations to kin, and wants to know how Euthyphro distinguishes between the pious and the impious, the good and the bad.

Euthyphro provides a series of definitions each of which Socrates knocks down. Socrates’ key question is this: Do the gods love the good because it is good, or is it good because it loved by the gods? Unless the gods love something for no good reason, then they must love something as pious because it inherently possesses value. But if it inherently possesses value, then it does so independently of the gods. Or, as Leibniz asked at the beginning of the eighteenth century, if it is the case that whatever God thinks, wants or does is good by definition, then ‘what cause could one have to praise him for what he does if in doing something quite different he would have done equally well?’ If, on the other hand, God recognizes what is good and promotes it because of its inherent goodness, then goodness must exist independently of God. It might now make sense to revere God’s goodness. But God is no longer the source of that goodness, nor do we need to look to God to discover that which is good.

One answer may be that God cannot but be good, so the dilemma is ill-formed. If God and the good are one and the same, then we cannot ask whether God chooses good because it is good – the very question separates that which is inseparable. But we can restate the Euthyphro dilemma in a different way, to meet such an objection. We can ask: Is God good because to be good is to be whatever God is; or is God good because He has all the properties of goodness? If it is the former, then we find once more that goodness is arbitrary, since it would be whatever God happened to be. If, on the other hand, God is good because he has all the properties of goodness, then it means that such properties can be specified independently of God. And so the idea of goodness does not depend upon the existence of God.

Believers and non-believers, in other words, face exactly the same problem: that we as humans have to decide what is right and wrong. We both have to pick and choose. Of course we do not pick and choose values simply as individuals, or as we might pick and choose a shirt or a car. We live not simply as individuals but also as part of communities, societies, cultures, histories, traditions and, yes, faiths. It is always as part of a collective that we make our choices. But choose we do. And there is no getting away from the fact that we bear responsibility for our moral choices.

The difference between believers and atheists in not, then, that one picks and chooses moral values, while the other simply receives them from God. It is that I, as an atheist, accept that values are humanly created, while believers, having humanly chosen what is good and what is bad, then alienate this decision to God, because it seems provide those values with greater authority. So Christians who think that gays should be executed think that God has told them. So do Christians who believe that practising homosexuals have committed no sin.

The difference between atheists and believers on the question of moral values is, as with question of Creation, not a difference in how we define morality – both have to decide what is right and wrong – but rather about how we wish to explain it. One accepts it as a human creation, the other feels necessary to alienate that creation to God. The difference, in other words is between those who are happy to accept the unnerving thought that we live by our own morals and those who like to imagine that they can set their ethics in concrete by invoking the figure of God.

The third argument for the necessity of God is that without God there would be no meaning or purpose to life. In part the idea that God is necessary to infuse meaning into our lives derives from the belief that He is necessary for the creation and maintenance of the universe and for the establishment of an ethical framework. But if you reject both those ideas, as I have done, then the claim that one needs God to infuse life with meaning also falls.

But there is a broader issue here. In part, the argument that without God there is no meaning derives from the idea that, as William Craig has put it, ‘on the atheist view humans are just animals’. In fact I would argue the very opposite. Only an atheist view allows us to be truly human.

Religion played a vital part in the development of civilised life because it made possible the belief that there was more to life than mere animal existence. But the price of transcendence has been enslavement to the sacred. Religion attempts to give meaning and a dignity to our mundane existence through creating a relationship between the profane and the sacred. But in doing so, the sacred becomes a means of diminishing the sense of what it is to be human. ‘The sacred order’, as Leszek Kolokowski the Polish Marxist-turned-Christian philosopher, observes, ‘has never ceased, implicitly or explicitly, to proclaim “this is how things are, they cannot be otherwise”.’

For me to be human is precisely to reject the idea that ‘this is how things are, they cannot be otherwise’. It is about wanting to seize responsibility for human fate away from God’s hands so that humans can help shape their own future. Meaning and dignity derives not from the acceptance of fate, as in religion, but from our capacity to defy it.

I want to finish this talk with the French Algerian existential philosopher Albert Camus’ meditation on faith and fate in his book The Myth of Sisyphus. Written in the embers of the Second World War, Camus confronts both the tragedy of recent history and what he sees as the absurdity of the human condition. There is, he observes, a chasm between ‘the human need [for meaning] and the unreasonable silence of the world’. Religion is a means of bridging that chasm, but a dishonest one. ‘I don’t know if the world has any meaning that transcends it’, he writes. ‘But I know that I do not know this meaning and that it is impossible for me just now to know it.’

Camus does not know that God does not exist. But he is determined to believe it, because that is the only way to make sense of being human. Humans have to make their own meaning. And that meaning can come only through struggle, even if that struggle appears as meaningless as that of Sisyphus, who, having scorned the gods, was condemned by them to spend eternity in the underworld forever rolling a rock to the top of a mountain, only for it to roll all the way down again. The certainties of God – though not just of God, of course – provide false hope and in so doing undermine our humanity by denying human choice.

For Camus, religious faith must be replaced not with faithlessness but with a different kind of faith: faith in our ability to live with the predicament of being human. And in so doing, Camus made fate a matter of human action, not of divine intervention or of natural cause. It was a courageous argument, especially in the shadow of the Holocaust. It was also a challenge that remains as important today as it was then.

The human condition is that of possessing no moral safety net. No God, no belief in God, no amount of ethical concrete, can protect us from the dangers of falling off that moral tightrope that is to be human. That can be a highly disconcerting prospect. Or it can be a highly exhilarating one. Being human, the choice is ours.