Today I have been defending New Atheism in the morning, and will be attacking it in the evening. At 9am, I debated the Christian theologian Alister McGrath, author of the wittily titled Dawkins Delusion and critic of New Atheism, on Christian Premier Radio. You can bet I swotted up on my Dawkins and Hitchens for that. But at 6pm at the Royal Society of the Arts the magazine I edit, New Humanist, will be hosting a debate called "After New Atheism: where next for the God debate" where the panellists – award-winning novelist Marilynne Robinson, conservative philosopher Roger Scruton, historian Jonathan Rée, the whole thing chaired by Laurie Taylor – will be invited to consider how we can move beyond the crude and simplistic perspective on religion popularised by New Atheism.

Does this make me a hypocrite? I'm going to say "no", though I would wouldn't I? The fact that I can both defend and attack it represents my ambivalence about the phenomenon of New Atheism, or more precisely my certainty that New Atheism is very good at some things and bad at others. For the purposes of what follows I use New Atheism as a somewhat baggy but, I think, useful shorthand for the trenchant anti-religion polemics of Richard Dawkins, Christopher Hitchens, Daniel Dennett (though he is more scientific and more polite) and AC Grayling, plus a few others.

One thing it's certainly good at is generating interest: speaking as a professional godless editor, New Atheism has been very good for business. Hundreds of column inches have been generated by New Atheism and responses to it – not least in my magazine – and, if at times the debate has all the subtlety of It's A Knockout, it has also been educative, instructive and popular, in the important sense that it has been conducted in a language that most people can understand. It's sold a lot of books, too.

New Atheism is also good at answering back to particular kinds of arguments. The origins of the New Atheists' impulse, according to philosopher Richard Norman, lie in 9/11 and the reappearance of a particularly aggressive strain of Christian religious fundamentalism. If, as Norman also argues, New Atheism can be over-generalising and crude in its response to religion, this is because it is a response to crude and nonspecific articulations of religiosity – what could be less specific than bombing a skyscraper, or cruder than Biblical creationism?

In the light of this, irascible, rhetorically florid, sweeping, intellectually arrogant New Atheism certainly has its place – some arguments are just asking for it. Perhaps the classic New Atheist quote is Dawkins's response to those who accuse him of dismissing theology from a position of ignorance: "Look," he told Laurie Taylor, "somebody who thinks the way I do doesn't think theology is a subject at all. So to me it is like someone saying they don't believe in fairies and then being asked how they know if they haven't studied fairy-ology."

There is a crisp logic here. I agree with Dawkins. But in another interview, this time with a fierce critic of New Atheism, Terry Eagleton says: "Imagine someone holding forth on biology whose only knowledge of the subject is the Book of British Birds and you have a rough idea of what it feels like to read Richard Dawkins on theology." Put this way, Eagleton seems right. I agree with him, too.

Because entertainment value aside it is surely false, as well as politically unwise and, well, pretty impolite, to say that "all theology" is irrelevant (some of it is moral reasoning, isn't it?), still worse to say that "religion poisons everything", or that without religion there would be no war, or that bringing a child up within a faith is tantamount to child abuse, or that moderate religious believers are worse than fundamentalists because they prepare the ground for extremism, or that "all" religion is this, or that, or "all" faith is misguided, or to suggest that those who believe in God are basically stupid, or that science, and only science, can answer our questions.

The picture of religion that emerges from New Atheism is a caricature and both misrepresents and underestimates its real character. "Religion," Richard Norman writes "is a human creation … a mirror which humanity holds up to itself and in which it sees itself reflected. Human beings attribute to their gods all their own human qualities – cruelty revenge and hatred, but also love and compassion and mercy. That's why you can find a justification for anything, good or bad, in religion."

This may be less fun than denouncing the pope and all his works, but it's closer to reality. For Norman, as a humanist, the requirement is to be less strident so as to create alliances with moderate religionists on specific topics – faith schools, fundamentalism, terrorism – of concern to all. I second that, but I have a more base reason for wanting to move beyond New Atheism. I'm bored, and I fear my readers are becoming so too.

So the purpose of this evening's event is to see if we can find a mode of inquiry into religion, faith, belief and non-belief, more consistent with William than with Jesse James.

It might be that we will map out a new, specific, patient and subtle future for the God debate. But let's be clear, no matter where we decide to go we wouldn't be where we are now if we hadn't had five good years of irascible, impatient, blunt, godless discourse – New Atheism – to leave behind.

• Watch the RSA / New Humanist Debate "After New Atheism: where now for the God debate?" live at 6pm on Tuesday 21 September