I'll mention only briefly the contradictions, logical fallacies and outrageous hypocrisy—not to mention Godwin's Law for the loss—of John Cornwell's slanderous anti-Dawkins diatribe masquerading as an "essay", which The Guardian inexplicably saw fit to publish. We've seen this sort of bullshit a thousand times before, and we know how to spot the errors. We know too that fisking every ludicrous assertion and offense against reason, logic and sensibility will not penetrate a picometer into the faith-addled goo that passes for Cornwell's brain.
I'd rather discuss what Cornwell's title promises (although the essay does not deliver): "The importance of doubt."
Like most words "doubt" has multiple meanings. An equivocation between two of these meanings—lack of conviction and lack of certainty—is the central fallacy underlying much of the judge-nothing (but judgment), criticize-nothing (but criticism), tolerate-everything (but intolerance) bullshit postmodernist anti-atheist backlash. While certainty entails conviction, conviction does not entail certainty.
Cornwell clearly ascribes certainty to Dawkins. He does not in any way rebut or even mention Dawkins' actual reasoning: That Dawkins does not "doubt" (that he's convinced) that theism, superstition and irrationality are bad is by itself not only evidence of absolutist certainty but also of Stalinism and Nazism. (One must wonder why Cornwell's vaunted tolerance and pluralism, apparently higher ethical principles than mere truth, do not extend to Stalin and Hitler.)
To the skeptic doubt is not an attitude of non-conviction. It is rather a tool: It is the process itself of subjecting our beliefs to both logical and sensible scrutiny, and the commitment to accept only those beliefs which pass that scrutiny. We are convinced because we doubt, because we ourselves have subjected the belief to the scrutiny of reason. Doubt in this sense is the expression of uncertainty: One can be certain of a belief only to the extent that evidence—or even logic—is irrelevant to that belief.
The supposed coexistence of faith and doubt—in either sense of the word—is a transparent sham. To have faith in something is, of course, to be convinced of it. But can we, even with all the charity in the world, conclude that some believers do in fact "doubt" in the sense that are not certain of their faith?
I say no.
To be uncertain about a belief entails that you're going to subject that belief to some sort of externalized scrutiny. Naturalists use logic, reason and the evidence of their senses, and all but the most die-hard solipsist accepts that the senses are externalized. But religious believers do not do so. At best, the only "scrutiny" they perform is purely internal: "Do I still believe? Yes!" Absent this externalized scrutiny, even the "uncertain" sense of doubt is not justified.
So what do these doubting theists actually mean by "doubt"? They relegate beliefs about God to the status of mere opinion. In this sense, it's very easy to see the basis of their criticism of Dawkins, et al.: It is ludicrous to assert the truth of any opinion. It's just as ridiculous to assert that it's objectively true that Brussels sprouts are disgusting as that they're tasty.
But relegation to opinion does not employ the meaning of "doubt" in either sense: I'm certain, and thereby convinced, what my opinions actually are. I'm certain that, at least right now, that Brussels sprouts disgust me. I don't doubt the proposition in any sense. (Of course my opinion might change, and I will take the odd bite now and again to find out, but I know with certainty what my opinion is right now.)
And this relegation to opinion is bullshit anyway. Beliefs about God are beliefs about objective truth, about all of reality. To label one's beliefs about God as opinions is to say the beliefs are about nothing other than one's own self. But if that were actually the case, why take umbrage at Dawkins or any other atheist? Among the thousands of atheists I've met or talked with—some of them quite stupid—not a single one has ever asserted that the word "God" has magical evil mojo. Dawkins himself goes out of his way to mention that no atheist objects to "Einstein's God" and the like. (Einstein's word choice, trivially unobjectionable on its own merits, might have increased confusion among the faith-heads. But since the faith-heads seem thoroughly confused already, it's hard to measure any sort of actual increase.)
"God" is a matter of truth, and private "opinions" about the truth never stay private. The relegation of beliefs about the truth to opinion is a dishonest, disingenuous rhetorical tactic to both shield one's own beliefs from critical scrutiny as well as to denounce others' beliefs also without critical scrutiny. It is not only the antithesis of doubt, it is an offense against reason itself.