Anthony, we’re going to talk about five books which weigh religion and secularism. I think that’s how we’ve decided to frame this discussion? 

The first book that I’ve chosen is from a long time ago: 1670. It was written by Spinoza and published after his death. It’s called "Tractatus Theologico-Politicus" and there are a number of reasons why I think people should read it. One is that it is way ahead of its time in its understanding of the human nature of traditional religion, and on the place of religion in society. Another reason, which has nothing particularly to do with religion, is that it’s intelligible, unlike Spinoza’s "Ethics", which you really need to have studied quite a lot of philosophy to understand. The "Ethics" is the work of Spinoza’s that people try to read, but most of them get very little out of it. His "Tractatus", by contrast, is intelligible to everybody, doesn’t require any philosophical background, and does give you many of the main themes of Spinoza’s thought.

And what are those themes?

Well, with regard to God, I suppose the most famous ideas expounded in the "Ethics" is that God is equivalent to nature, in some sense, and so should not be thought of as a personal being. 

So God is not like us?

God is certainly not like us: he doesn’t have emotions and wishes in the normal sense. So that’s one thing. But the first task Spinoza set himself in the "Tractatus" is to undermine the traditional notion of the Bible as the inerrant word of God. (In fact, the "Tractatus" is arguably the first serious work of biblical criticism.) He takes the five so-called books of Moses and shows why they probably aren’t by a single person, and certainly not by Moses.  As he goes through the various books of the Old Testament, what he’s out to establish is that these writings reflect human ideas, and that they are  the ideas of particular people expressed at a particular place and a particular time. Most educated people accept that now, but it was a horrifying idea to the religious establishment in Spinoza’s time.

So the Bible is man-made, and for this reason, nobody can use it to claim ownership of a divine authority.

No, and certainly not the Jews. Spinoza was Jewish by birth, though he was famously excommunicated by his synagogue, and one of the things he sets out to do in the book—and does, I think, very well—is attack the idea that the Jews were the chosen people, or more beloved by God than anybody else.

I think his books were also banned by the Catholic church?

Yes, because he was generally thought of as an atheist, though he certainly wouldn’t have described himself as one. He thought he was just trying to show what God was really like, and in fact the German poet Novalis called him a “God-intoxicated man,” with some justice, because Spinoza never stops talking about God. Well, you can’t be both God-intoxicated and an atheist.  But you can, of course, be both God-intoxicated and yet unimpressed by traditional Judaism. Spinoza thought that the rules by which Jews lived, as derived from the bible, merely reflected the circumstances of the early state of Israel, and because Israel no longer existed, and times had moved on, he thought these rules had become irrelevant. The dietary laws and so forth, that bound the religious community of his time, and which continue to bind the orthodox, were all based, he felt, on a misunderstanding. It was a mistake to suppose that God wanted you to go on living like that even today.

Didn’t he choose circumcision in particular to exemplify the man-made nature of divine law?

Yes, and interestingly he thought that circumcision was actually key to the survival of the Jews: it was a way in which they marked themselves out and bound themselves together.  This was shocking at the time. Another thing that people found shocking was Spinoza’s notion of religious toleration and of the separation between church and state. So whether or not you think he was an atheist or a theist, he was certainly a secularist. He thought that religion had no part to play in politics. He was, by the way, writing in one of the most secular states at the time, where there was most religious freedom: Holland.

Can you tell me briefly how Spinoza did conceive of God?

He thinks of God as identical with nature, which is a slight simplification of what he said, but will do for now. That is a radical reinterpretation of the idea of God, but on the other hand Spinoza thinks that there is a supreme being who is omnipotent, omniscient and omnipresent—which are the traditional attributes of God. Because he does not think of God as a personal being, however, morality ends up being secularised—because if God is not like a person, then we should not think of him as having desires in the ordinary sense, or as issuing commands, so we have to think of the relation between God and morality in a new way. And Spinoza’s way is to say that God’s law is justice, charity and the love of one’s neighbour, and if you let those things govern your life, then you are in fact following God’s law. That’s all it takes to be godly. One thing that follows from that, of course, is that you can live a godly life while being an atheist. You might just want to do those things anyway, even if you think there is no God. Just so long as you are living a just and loving life, that’s the important thing about being godly. And I think it’s pretty plain that educated, moral, people today who are not religious would say, yes, that’s roughly what I think: if you want to talk about “God’s will”, you can say that living a moral life and doing God’s will come to the same thing. So Spinoza was a very modern thinker, a long, way ahead of his time.

Before we talk about Hume, who is the author of the next book you’ve chosen, one of the things that interested me about Spinoza was his rejection of Descartes’ mind/body dualism. He collapses the difference between the material and the spiritual world and in doing so he invites us to reject divine providence – the notion of a God who is different from nature and who is organising nature from outside. And by the same token he invites us to see that our own freedom is not so much the freedom to change what happens to us as to understand why it happens. Spinoza argues that once we understand this properly, we will understand that reality is the only perfection, and this is also what it means to become more godly.

Spinoza certainly had an unusual conception of freedom. To be free, for him, is to understand the ways in which you are determined. That is one of the hardest things to understand in Spinoza.

Whereas Hume is very sceptical about the degree to which anything can be rationally understood at all, isn’t he? Including why or if the sun will rise tomorrow—to say nothing of the nature of God.

Yes, the difficulty of demonstrating rationally anything much about God is the focus of my second book, which is Hume’s "Dialogues Concerning Natural Religion". This was published almost a hundred years after Spinoza’s "Tractatus"—again, it was published posthumously, because even in the relatively free-thinking atmosphere of late 18th century Edinburgh, Hume’s critique of religion was highly unacceptable. His friends urged him not only to give up the idea of having it published in his lifetime, but even of having it published after his death, because they thought that it would condemn all this other works to the dustbin of history. Nobody would read them, because they would write Hume off as a wicked unbeliever. But Hume insisted and took steps to ensure that the "Dialogues" would be published after his death, and he was right to have done so, because his works are now far from ignored. This one is probably the most read of all his books, and I think it’s arguably the masterpiece of English language philosophy.

That’s a terrific claim. Can you explain why?

The secret of its success is the way in which powerful and original arguments are woven into an elegant dialogue between three thinkers. The dialogue form is hard to pull off in philosophy, and Hume is one of the very few since Plato to be able to manage it. His announced topic here is “natural religion”. This is contrasted with “revealed religion”, and it means the sort of religious conclusions one can arrive at by reason rather than revelation. So for example, if somebody says “I know that Jesus wants me to do this, because he came to me in a vision,” or “because that’s my reading of scripture,” then that counts as revealed religion. On the other hand, if someone were to say that he is going to behave in a certain way, or that he believes in God, because of certain rational arguments, then that is natural religion. The part of natural religion that Hume focuses on in the "Dialogues" is something that is often called “the argument from design”, which is an argument for the existence of God that starts from the way the world works and is structured. The suggestion here is that the best explanation for what we observe is the existence of a designer—a god who made us. And this is of course a very familiar argument, with an intelligent, divine designer still offered by many people as a necessary supplement to science, as something that is still required by the evidence of complexity and apparent order in the universe.  What Hume does in his "Dialogues" is to undermine that line of thinking in a brilliant series of arguments that I don’t think have ever been bettered, let alone answered. They are more profound, I think, than the Darwinian critique of intelligent design. Hume, certainly would have endorsed natural selection if he had known about it. But it’s not enough to read Darwin and Dawkins. You have to read Hume as well to understand the flaws in the theistic argument from design.

And what is it particularly that Hume offers that goes to the heart of the matter?

One of the key ideas is the limitations of arguing by analogy in this context, which is the way the argument from design usually works. Take, for example, a watch found lying in a forest. You might say to yourself: this watch cannot have come together by chance. Somebody must have designed it and made it. Then, by analogy, you might reason: surely nature wouldn’t work as it does unless there were a designer who made it. Now one of the many things that Hume points out is wrong with this kind of analogy is that even if you accept the analogy in principle, it still wouldn’t get you to the sort of God we’re after, but only to a superior intelligence who had made the world and the creatures in it. This intelligence wouldn’t necessarily be everlasting, omnipotent, or omniscient…

And would himself require a designer…

Well that’s one of the clinchers. If you’re going to ask where everything comes from and who designed it, you really do have to ask the same of God. So if you put forward God as the explanation for nature, you’re also going to have to ask who made God.

Yes, a devastating argument. And the finishing touch, isn’t it, is that if a designer requires no designer then why does nature require a designer? What is the need for God at all? Which brings us back to Spinoza, effectively collapsing the difference between God and nature.

Yes. And one of the most striking things that distinguishes these Dialogues from contemporary anti-religious books like, for example, Dawkins’s "The God Delusion" or Hitchens’s "God is Not Great", is that none of Hume’s characters  ever actually puts himself forward as an atheist or agnostic. Even Philo, whose views are closest to Hume’s own, pretends to be a believer. Hume’s technique is to pretend that he is the true defender of religion, that he is just trying to strengthen religion by shaving off the weaker bits. Now the thing is that when you have read and sympathised with all of Hume’s writings on religion, you realize that he has in fact shaved away everything. But that is why he manages to be so persuasive. He takes the reader very gently.

Like Socrates in the "Thaeatetus".

Yes. It’s a very Socratic approach. And as an unbeliever myself, I think that technique is a much more effective way of showing religious people the error of their ways…

I’d wanted to ask you about that. About what you thought of Hitchens’s "God is Not Great" …

I think it’s the best of the bunch of the recent atheist books, and I sympathize with most of its conclusions. But I do think that it strays very much into misanthropy. Because, if you believe, as Hitchens and Dawkins and I believe, that religion was invented by people, then to hate religion is to hate people. Well that’s my main disagreement. And I also think that Hitchens is too quick to attribute harm in human history to religion, whereas I think that religion has also had a lot of good effects. And where it has bad effects one has to remember that this is people using religion to their own ends. It’s not as if there’s a Satan out there who created religion and who’s doing all these bad things. If you really are a naturalist and you don’t believe in the supernatural or God, then you have to remember that the harm religion does is the harm that people do.

We’ve talked about Spinoza and Hume. Spinoza who believed in God but not in religion. Hume who did not, perhaps, believe in God at all.

Well if you were to ask Hume whether he believed in God or not, or alternatively, whether one simply could not answer questions of that kind in any sensible way, he would have to say the latter, though he certainly wasn’t tempted by any religious belief. He was a consistent and extreme empiricist. He thought that what the human mind could divine one way or another was very limited.