Author Q&A: Anthony Gottlieb

The Dream of Enlightenment: The Rise of Modern Philosophy (Allen Lane, £20, Kindle £10.99, Audible £20.49) covers the period from the 1640s to the French Revolution, when philosophers Descartes, Hobbes, Spinoza, Locke, Leibniz and Hume all made their mark. Lucid explanations of their thought combine with wider historical context.

Your new book picks up where The Dream of Reason, about philosophers from Ancient Greece to the Renaissance, left off.
Did you anticipate there would be 16 years between them being published?
No, and neither did my publishers. I had a full-time job for almost half of that period, and was then involved in other projects too. But the main reason for the delay was that I needed to do a lot of reading and pondering before I felt ready to pronounce on these topics. And it was reading not just about philosophy and science but also European history. I wanted, for instance, to know more about British politics in the 17th century to understand some of what Hobbes and Locke were trying to say.

You write about two staccato 150-year bursts of western philosophy: 5BC-4BC in Athens, and 17th-18th century northern Europe. Why do you think there were no other such bursts in between?
There were, of course, other bursts of intense intellectual activity after Athens kicked it all off – the middle of the 13th to the middle of the 14th century, for example. But it seems that the rise of modern science, and the aftermath of Europe’s religious wars, stimulated fresh thinking that is of especial interest to the modern world. It’s not that people were suddenly cleverer than they had been in the Middle Ages. It’s that the 17th and 18th century thinkers speak more directly to us, because their problems are still our problems.

Was the “cold bath of scepticism” of Descartes what united Enlightenment philosophers or was it something else?
Descartes’ engagement with scepticism is a convenient place to begin the story of modern philosophy, in the narrow, technical sense of “philosophy”. His work had a uniquely large influence on other philosophers, at least at first and on some topics. Some thinkers were starting to believe that plenty of old ideas need questioning, and Descartes’ vivid way of doing that, by playing the part of a sceptic who doubts almost everything, was exemplary. But if we use the term the “philosophy” more broadly, to include the questioning of social and institutional authority in modern and early modern times, then Descartes’ contribution to Enlightenment philosophy is not quite so seminal. He focused on broadly scientific issues, and the puzzles that arise from them, not on political, social and religious ones.

Do we make too much of what they had in common when in fact they were very diverse?
Hasty generalisations are rife when it comes to the Enlightenment, because the term is now used so loosely – to cover almost anything, anywhere that was post-medieval and broadly progressive. I think the best policy is to regard Voltaire and the philosophes in 18th century France, and their sympathisers, as the core of the Enlightenment, and to bear in mind that these people saw themselves as the heirs of 17th century figures such as Descartes and Locke. It’s also important to bear in mind that they were in some respects following in the footsteps of highly controversial – indeed, infamous –17th century thinkers such as Hobbes and Spinoza, whose influence they could not always openly acknowledge. There was, of course, great diversity even within this core. But I think you can reasonably say that the key Enlightenment thinkers were united by a self-conscious enthusiasm for questioning authority and starting afresh.

Should we be surprised that many Enlightenment philosophers also believed in God?
In a word, no. Until the late 18th century it was more or less unthinkable that the wonders of nature might have come about without a divine creator. And even then, it was pretty rare to think that God might be superfluous. It took another century or so before unbelief became acceptable for significant numbers of highly educated people. Also, plenty of thinkers who were famously critical of religious institutions and of some Christian dogmas, such as Voltaire, believed that society would collapse if the masses did not believe in some sort of God. Criticisms of traditional religious ideas by Hobbes, Spinoza, Locke, Voltaire and Hume did, I think, eventually contribute to undermining belief in God – just as their conservative enemies at the time said that they would.

What do you make of Isaiah Berlin’s suggestion that the seeds of totalitarianism can be found in some of the philosophes?
Some historians of ideas spend too much time looking for seeds. A handful of the philosophes wrote some things that could give succour to later totalitarians, if ripped out of context. But even if you think that a thinker can be held responsible for later abuses of his ideas, there can be little doubt that the philosophes would have condemned 20th century communism and fascism.

What relevance do the Enlightenment thinkers have for today?
Here are some maxims that are distinctive of Enlightenment thought as I see it. You know less than you think: look at the evidence more carefully, and try to be as rational as you can. Don’t try to impose your religious beliefs on anybody else. Rulers and public institutions exist to serve people, and not the other way round. Unfortunately, these things still need saying.

With the rise of Isis and man-made climate change do we live in a post-Enlightenment world?
With respect to Isis, I’d say they live in a pre-Enlightenment world. It’s not that the old medicine didn’t work, but that they don’t want to try it. As for climate change, I think the fact that educated people are trying to use scientific methods to understand and ameliorate it illustrates the success of Enlightenment ways of thinking.