Richard Dawkins is not alone in his refusal to debate with William Lane Craig. The vice-president of the British Humanist Association (BHA), AC Grayling has also flatly refused to debate Craig, stating that he would rather debate "the existence of fairies and water-nymphs".

Given that there isn't much in the way of serious argumentation in the New Atheists' dialectical arsenal, it should perhaps come as no surprise that Dawkins and Grayling aren't exactly queuing up to enter a public forum with an intellectually rigorous theist like Craig to have their views dissected and the inadequacy of their arguments exposed.

Ironically, there is nothing substantively new about the New Atheists either. Despite its self-congratulatory tone, The God Delusion contains no original arguments for atheism. Summarising what he calls "the central argument of my book", Dawkins insists that even without an entirely convincing explanation for the fine-tuning in physics, the "relatively weak" explanations we have at present are clearly better than "the self-defeating … hypothesis of an intelligent designer".

Dawkins maintains that we're not justified in inferring a designer as the best explanation of the appearance of design in the universe because then a new problem surfaces: who designed the designer? This argument is as old as the hills and as any reasonably competent first-year undergraduate could point out is patently invalid. For an explanation to be successful we do not need an explanation of the explanation. One might as well say that evolution by natural selection explains nothing because it does nothing to explain why there were living organisms on earth in the first place; or that the big bang fails to explain the cosmic background radiation because the big bang is itself inexplicable.

What is new is the belittling posture toward religious believers and the fury of the polemics. The New Atheism is certainly a far cry from the model of civilised interlocution between "old atheist" Bertrand Russell and Father Copleston that took place and was broadcast on BBC Radio in 1948. The New Atheists could learn a lot from the likes of Russell, whose altogether more powerful approach was at once respectful and a model of philosophical precision.

In his latest undignified rant, Dawkins claims that it is because Craig is "an apologist for genocide" that he won't share a platform with him. Dawkins is referring to Craig's defence of God's commandment in Deuteronomy 20: 15-17 to wipe out the Canannites. Here is Craig's offending passage:

"[If] God's grace is extended to those who die in infancy or as small children, the death of [the Canannite] children was actually their salvation. We are so wedded to an earthly, naturalistic perspective that we forget that those who die are happy to quit this earth for heaven's incomparable joy. Therefore, God does these children no wrong in taking their lives."

I am disinclined to defend the God of the Old Testament's infanticide policy. But as a matter of logic, Craig is probably right: if an infinite good is made possible by a finite evil, then it might reasonably be said that that evil has been offset. However, I doubt whether Craig would be guided by logic himself in this regard and conduct infanticide. I doubt, that is, that he would wish it to be adopted as a general moral principle that we should massacre children because they will receive immediate salvation.

But whatever you make of Craig's view on this issue, it is irrelevant to the question of whether or not God exists. Hence it is quite obvious that Dawkins is opportunistically using these remarks as a smokescreen to hide the real reasons for his refusal to debate with Craig – which has a history that long predates Craig's comments on the Canaanites.

As a sceptic, I tend to agree with Dawkins's conclusion regarding the falsehood of theism, but the tactics deployed by him and the other New Atheists, it seems to me, are fundamentally ignoble and potentially harmful to public intellectual life. For there is something cynical, ominously patronising, and anti-intellectualist in their modus operandi, with its implicit assumption that hurling insults is an effective way to influence people's beliefs about religion. The presumption is that their largely non-academic readership doesn't care about, or is incapable of, thinking things through; that passion prevails over reason. On the contrary, people's attitudes towards religious belief can and should be shaped by reason, not bile and invective. By ignoring this, the New Atheists seek to replace one form of irrationality with another.