‘Have courage to use your own reason!’- that is the motto of enlightenment.
-Immanuel Kant (d. 1804)

There is probably no more significant movement in intellectual history than that we know of as ‘the Enlightenment’ of the 18th century, though the Athenians of the 4th century BC might contest it. Even two hundred and fifty years on, we live our everyday lives in its wake—especially in the area of religious belief. How can we deal with its legacy?

The Enlightenment, which culminated in the revolutions in France and in the United States, saw the birth of the political rights and freedoms we very much treasure today. It spelt the end of the dominance of the aristocracy, and the rise of democracy. It also paved the way for the Industrial Revolution, and for the development of free market economics. We cannot think of our smart phones—and the ability for an ordinary person to own one—without either of these.

The Enlightenment is also sometimes called ‘The Age of Reason’, because the group of thinkers that represent this epoch saw themselves as attempting to ground everything on rational, rather than traditional, principles. Authority was to be questioned rather than accepted, so that reason could have its way. The principles and methods of scientific investigation emerge from this period, because it turned out to be a very successful strategy for gaining knowledge about the world. For example, medicine done on the basis of an accepted tradition was not nearly as good at curing people as medicine based on empirical reason. This is why we have decided that bleeding people to cure them of fever is dumb, and that vaccination saves lives.

And this was very much a religious movement, in its way: which is to say that the Enlightenment was very interested in religious questions, and put forward some distinct answers. Very few Enlightenment thinkers were out and out atheists, but traditional Christian ideas came under severe attack in the eighteenth century. Often this was depicted as a response to the bitter wars between European states in the seventeenth century, which were often depicted as being religious in nature. How could Catholic and Protestant be made to stop killing each other, if they seemed incapable of finding a common authority? If religion could be based on reason alone, then there could be an objective and hopefully peaceful discussion about it, surely.

It might also be possible to remove the government of the religious impulse from the clutches of the ecclesiastical institutions which seemed uninterested in the investigation of new ideas.

For John Locke, the English philosopher of the early Enlightenment, this meant basing his thinking in large part on a thorough exegesis of Scripture wholly unmediated by any church authority. Locke is still regarded today as the father of ideas like political liberty and equality, and religious tolerance, but his reliance on the Bible is usually passed over in embarrassed silence.

There were three particular challenges to traditional Christianity in this period. The first of these relates to the identity of God, and his relationship to the world. As I said before, few Enlightenment thinkers were atheists. Rather, many of them (including the American Thomas Paine) embraced ‘deism’. Deism is the belief that God is a creator, but does not have an ongoing role in the government of the world. God is watching us, but from a distance. He sets up the principles and laws by which the world runs, but does not further intervene. It was rational to believe in God, but not to believe in the teaching of the institutional churches about the life and death of Christ. It was the business of human individuals to live a morally dutiful life on the basis of reason, rather than simply give obedience to divine commands, or to church teaching.

This theological idea runs directly counter the orthodox Christian teaching about the Trinity. The Christian God is not simply remote, but is intimately involved with the universe he creates—to the point of becoming a creature within it. Deism was challenged during the Enlightenment, mind you: but it represented a step away from orthodox Christianity scarcely imaginable a century before.

It was dependence on reason alone that led the Scottish philosopher David Hume (secondly) to challenge the traditional belief in the miracles narrated in the Bible. For Hume, the laws of nature are fixed and unalterable. A miracle is by definition an event that happens in opposition to the laws of nature. Hume argued that a miracle is so unlikely that it is far more likely that the report of a miracle is the result of a delusion or a hoax. Traditional Christianity’s dependence on miracles was simply superstitious.

Thirdly, the Bible itself was opened up to critical study. If, as Hume said, you couldn’t believe in miracles, then what was one to do with the miracles claimed in the Bible? Could the Bible really be the basis for a revelation of God? Scholars began to ask not ‘what does the Bible say?’ but ‘who wrote the Bible?’ and ‘what can it tell us about history?’ At the extreme end of this was Thomas Jefferson’s creation of the ‘Jefferson Bible’, where he literally took a razor to the miraculous parts of the Bible, leaving behind what he felt were the more acceptable, moral parts. At a more serious scholarly level, Hermann Reimarus (d. 1768) argued that the historical Jesus was a political agitator, and that the resurrection was fabricated by the disciples.

This interlocking trio of ideas is still very much the agenda for contemporary theological thinking and biblical scholarship even today. Just as the scientific method operates in a world in which God is set aside as an explanation (which is of course appropriate), post-Enlightenment theology also proceeded with God virtually bracketed out.

But the Enlightenment didn’t kill religious belief—far from it. The 18th century was the era of the German pietists, and of the evangelical revivals—of Spener and Zinzendorf, Edwards, Wesley and Whitfield. If the Enlightenment was an appeal to the head, the evangelicals appealed to the heart. The powerful experience of conviction of sin, repentance and conversion to Christ was in a sense a trump card over and against any of the cold reason of the Enlightenment. At the same time, something of the anti-institutional spirit of the Enlightenment was captured in the evangelical emphasis on personal conversion unmediated by church authority—which the Enlightenment had in its turn arguably learnt from Protestantism in the first place.

What does the Enlightenment of two hundred years ago mean for contemporary Christianity? We cannot put the Enlightenment genie back in the bottle. Some Christians like to imagine that they can do this: that they can think about their faith as if the Enlightenment never occurred. At the same time, they enjoy the benefits that this movement of thought has bestowed on the world—laptops, modern medicine, political freedom. This to me seems somewhat hypocritical. The Enlightenment view of the world is persuasive because it is highly successful. It has produced an extraordinary fruit of blessing for the world—in God’s good providence (I say somewhat cheekily).

Having said that: even though the Enlightenment was anti-dogma and anti-tradition, it has produced its own dogmas and traditions too. Some of its great tenets have not been sufficiently questioned. Hume’s argument against miracles is certainly not a strong one, for example. Though the Enlightenment questions about the historicity and origins of the Bible still dominate, there have been powerful scholarly defences of its historical accuracy and coherence.

But more that: in its emphasis on the power of human reason, the Enlightenment rested on an incomplete view of the human individual. The Enlightenment hope was that the individual human person could live the moral life aided by reason alone—a thought that is still very much in evidence. This is inadequate for two reasons: the first being that although reason is a very significant part of us, it is certainly not the whole of us. Our ‘reason’ is not untainted by emotion. ‘Reason’ is often in fact used to justify what our hearts have already decided. What we need is a way of speaking about the shaping of the human heart.

The Enlightenment was also far too optimistic about the ability of a human being using reason to liberate him or herself from the habitual human lapse into evil and corruption. Can reason alone be the path out of the mire in which we find ourselves bogged? The ancient Scriptural doctrine of sin has nowhere been less verified than in the centuries following the Enlightenment. Sin is irrational, and our reason should indeed tell us what is good and right. But we are never simply rational, and our reason is always distorted by our evil desire. The Enlightenment doubted the Christian God; it should have doubted the human heart.