The famous Christian apologist William Paley wrote his Evidences of the Existence and Attributes of the Deity in 1802, drawing on a tradition of natural theology that was already strong in the Church of England and elsewhere. His evidences had a strong influence on Darwin, and have been the subject of debate ever since.

There does seem, however, to be a subtle change in the style of the debate. Even Richard Dawkins admits to the stunning nature of the work that Paley did, although, of course, he does not draw Paley’s conclusion. Other atheist comments I have heard recently, however, are rather different. They simply take the line that there is no evidence for the existence of God.

This seems at first like a mere linguistic difference – but linguistic differences can be important. Consider how the word ‘evidence’ is normally used. The most obvious example is within the legal system. The police or plaintiff marshal the evidence that a crime or injustice has been committed, and it is a matter of judgement as to whether the evidence points to guilt or not. This decision is made on the balance of evidence, which in criminal cases must be beyond reasonable doubt.

There is a huge difference between the statement that there is evidence for something but on balance it is not strong enough to prove a point; and the statement that the evidence does not exist. It would seem odd if the judge at a trial simply dismissed evidence brought by one side or the other without giving any reason. A judge can, of course, set aside evidence, but only if there is good reason to do so – for example, a statement might have been obtained under duress. Ignoring evidence without reason would rapidly undermine our whole system of justice.

Paley argued from the intricacy to be seen in living organisms, but it doesn’t matter which particular argument we are talking about. Another common one is the argument that the chain of cause and effect that we see everywhere in the universe implies that there must have been a first cause that brought everything into existence. Yet another frequent argument is that the existence of a universal morality implies an absolute moral law and lawgiver.

These are all well-known, as are the counter arguments from (for example) neo-Darwinism, particle physics or evolutionary psychology, and of course everyone is entitled to his or her own opinion. Yet simply to dismiss the evidence is ingenuous. The evidence concerned is what you could call ‘first order’  – we can easily observe the intricacy of the natural world, cause and effect and the existence of morality in relation to people’s behaviour. To question the conclusions drawn from evidence is fine, questioning the reality of evidence which palpably exists is not.

This would still seem pedantic were it not for the course upon which some science is now embarked. The evidence base for neo-Darwinism, particle physics and evolutionary psychology is far from ‘first order’ in the sense I have defined that above. Neo-Darwinism has to create a timeline of billions of years which cannot be directly examined. Particle physics is dependent on millions, if not billions, of calculations emerging from machines like the Large Hadron Collider and its network of countless computers. Evolutionary psychology has to draw conclusions about the intangible from the tangible (physical) information available.

In all these cases, the conclusions drawn may be valid or they may not. That’s not the point. The issue is that if the relatively clear evidence drawn on by theists is ruled out of court, then this scientific evidence should receive the same treatment. Otherwise there are going to be severe distorting elements in any discussion – a level playing field should not be undermined at one end, or it won’t be level for very long.

It’s two hundred years since Paley marvelled at the mechanisms and structures that he saw so acutely. But the real debate seems to have changed. It is no longer about the evidence of nature, rather it is about the nature of evidence.