My good friend Peter Atkins has written that ‘atheism is the apotheosis of the enlightenment’, and that ‘scientific method is a gloriously optimistic flowering of the human intellect’. The latter statement I agree with; the former seems historically inaccurate. There were many varieties of enlightenment, but most were theistic – Immanuel Kant asserted that belief in God was necessary, and even the French invented a ‘religion of Reason’. Those, like David Hume’s version, that were not theistic were also sceptical of the power of human reason.

There is a deeper philosophical point here: belief in the intelligibility of the universe and the power of human reason to understand it has usually been associated (as in Isaac Newton) with the existence of a rational God who made the universe intelligible (created it through Logos or Reason). Those who exorcise God (like Nietzsche) have seen little reason to think the universe is intelligible or that the human mind can understand it. So Peter’s claim that science is optimistic about discovering the nature of the cosmos, whereas religion is not, seems upside down.

In any case, it is a gross over-simplification to juxtapose ‘science’ and ‘religion’, and say that one is optimistic and the other pessimistic. There are many forms of science, and many pessimistic scientists. And there are many forms of religion, some of which are extremely optimistic about the scope of reason (late medieval thinkers like Anselm thought reason could prove virtually every truth, even about God).

Science, says Peter, is about experiment, repeatability, and public confirmation. That is broadly true. But it is not just religion, it is all the humanities – literature, art, music, morality, philosophy, and history – that lack these basic features of scientific method. There are no repeatable experiments and no conclusive tests that could show whether Heidegger is a profound philosopher or Rubens a great painter. That does not show that there are no rational criteria of judgment, no uses of reason, in these areas, that they are merely founded on sentiment. So in religion, Oxford’s Theology Faculty uses critical reasoning to examine varied linguistic, textual, cultural, historical and philosophical aspects of religious beliefs, and lays down no preconditions about what researchers may personally believe.

It is critical reasoning – applied to atheism as well as theism – that is the true apotheosis of the enlightenment. And it is quite possible to belong to a religious tradition and use critical reasoning about your own tradition. Critical religion asks if its basic beliefs are consistent with those of the sciences, if other traditions and philosophies – including atheism – have good arguments for other ways of believing, if traditional formulations need to be revised, and whether beliefs are harmful or beneficial in personal and social life. It may be that not many people are good scientists, and that not many people are good at critical thinking about religion. If so, we should try to educate more people in critical thinking – but that means getting them to challenge over-simple views of both science and religion, and to understand how people form basic world views that are not conclusively verifiable by science.

Peter says that science tries to make things simple, whereas religion tries to make them complex. Try comparing quantum theory with the religious claim that an intelligent God created the cosmos to generate finite intelligent beings that could understand and appreciate it. Which is simpler? Does it even make sense to compare them for simplicity? Is this not like comparing apples and prime numbers? Many sciences strive for simplicity, in the sense of having a few general laws and forces which may account for observed complex physical behaviour. Religion is not even in that game. Religion, in some of its advanced forms, seeks a different sort of simplicity, namely, one general reason, or at least a relatively small and coherent set of reasons, for the sake of which the cosmos exists. There may not be one, but the idea of God is the postulate of one being which could provide one such general reason or purpose for the cosmos. That is simplicity, but a different sort of simplicity.

Peter says, however, that there is not the ‘slightest evidence’ that the universe has a purpose. That is simply not true. There are hundreds of eminent scientists – I cite only Isaac Newton, Freeman Dyson, and Francis Collins – who think there is discernible direction in cosmic history, from relatively simple, unconscious structures to conscious structures of organised complexity. The direction is set by the basic constants and forces of nature, and seems to lead, as even Richard Dawkins once said, almost inevitably to the existence of intelligent conscious life sooner or later. That is evidence for purpose, though of course such claims are disputed and do not have overwhelming force. Nevertheless, it is a huge exaggeration to say that there is nothing at all that points to purpose in the universe.

My chief problem with Peter’s article, then, is that it vastly over-generalises, over-simplifies, and historically distorts, the very complex relationships between scientific and religious beliefs. ‘Science’ is presented as optimistic, rational, and leading to true understanding. ‘Religion’ is pictured as founded on sentiment, prejudice and unexamined faith. But there is more to understanding than scientific understanding. There is the understanding of what it is to live a good human life, what it is that gives value to life, and why it is that humans see their lives in such very different ways. Investigating such personal understanding is the province of the humanities, and religion is investigated within the humanities as one historically important way of understanding human existence that, while contested, is capable of rational criticism and defence.

Belief in the existence of God has seemed to most classical philosophers to be a central part of a reasonable, perhaps the most reasonable, perspective on human existence. To dismiss it because it does not conform to canons of scientific enquiry does not, overall, seem a wholly reasonable procedure. And that is the crucial question: can science alone give an adequate and reasonable understanding of human existence? If not, then wider philosophical, personal, and sometimes religious questions remain to be seriously addressed. When they are, God remains a serious candidate for rational and critical belief.