Of all the questions I fielded during the course of my recent book tour, the only ones that really depressed me were those that began "I'm an atheist, BUT . . ." What follows such an opening is nearly always unhelpful, nihilistic or – worse – suffused with a sort of exultant negativity. Notice, by the way, the distinction from another favourite genre: "I used to be an atheist, but . . ." That is one of the oldest tricks in the book, practised by, among many others, C S Lewis, Alister McGrath and Francis Collins. It is designed to gain street cred before the writer starts on about Jesus, and it is amazing how often it works. Look out for it, and be forewarned.

I've noticed five variants of I'm-an-atheist-buttery, and I'll list them in turn, in the hope that others will recognize them, be armed against them, and perhaps extend the list by contributing examples from their own experience.

1. I'm an atheist, but religion is here to stay. You think you can get rid of religion? Good luck to you! You want to get rid of religion? What planet are you living on? Religion is a fixture. Get over it!

I could bear any of these downers, if they were uttered in something approaching a tone of regret or concern. On the contrary. The tone of voice is almost always gleeful, and accompanied by a self-satisfied smirk. Anybody who opens with "I'm an atheist, BUT . . ." can be more or less guaranteed to be one of those religious fellow-travellers who, in Dan Dennett's wickedly perceptive phrase, believes in belief. They may not be religious themselves, but they love the idea that other people are religious. This brings me to my second category of naysayers.

2. I'm an atheist, but people need religion. What are you going to put in its place? How are you going to comfort the bereaved? How are you going to fill the need?

I dealt with this in the last chapter of The God Delusion, 'A Much Needed Gap' and also, at more length, in Unweaving the Rainbow. Here I'll make one additional point. Did you notice the patronizing condescension in the quotations I just listed? You and I, of course, are much too intelligent and well educated to need religion. But ordinary people, hoi polloi, the Orwellian proles, the Huxleian Deltas and Epsilon semi-morons, need religion. Well, I want to cultivate more respect for people than that. I suspect that the only reason many cling to religion is that they have been let down by our educational system and don't understand the options on offer. This is certainly true of most people who think they are creationists. They have simply not been taught the alternative. Probably the same is true of the belittling myth that people 'need' religion. On the contrary, I am tempted to say "I believe in people . . ." And this leads me to the next example.

3. I'm an atheist, but religion is one of the glories of human culture.

At a conference in San Diego which I attended at the end of my book tour, Sam Harris and I were attacked by two "I'm an atheist, but . . ." merchants. One of these quoted Golda Meir when she was asked whether she believed in God: "I believe in the Jewish people, and the Jewish people believe in God." Our smirking critic substituted his own version: "I believe in people, and people believe in God."

Religion, he presumably thought, is like a great work of art. Many works of art, rather, because different religions are so varied. I was reminded of Nicholas Humphrey's devastating indictment of an extreme version of this kind of thing, quoted in Chapter 9 of The God Delusion. Humphrey was discussing the discovery in the mountains of Peru of the frozen remains of a young Inca girl who was, according to the archaeologist who found her, the victim of a religious sacrifice. Humphrey described a television documentary in which viewers were invited . . .

" . . . to marvel at the spiritual commitment of the Inca priests and to share with the girl on her last journey her pride and excitement at having been selected for the signal honour of being sacrificed. The message of the television programme was in effect that the practice of human sacrifice was in its own way a glorious cultural invention – another jewel in the crown of multiculturalism . . ."

I share the outrage that Humphrey eloquently expressed: -

"Yet, how dare anyone even suggest this? How dare they invite us – in our sitting rooms, watching television – to feel uplifted by contemplating an act of ritual murder: the murder of a dependent child by a group of stupid, puffed up, superstitious, ignorant old men? How dare they invite us to find good for ourselves in contemplating an immoral action against someone else?"

It would be unfair to accuse our critic in San Diego of complicity in such an odious attitude towards the Inca 'ice maiden'. But I hope at least he will think twice before repeating that bon mot (as he obviously thought of it): "I believe in people, and people believe in God." I could have overlooked the patronizing condescension of his remark, if only he hadn't sounded so smugly satisfied by this lamentable state of affairs.

4. I'm an atheist, but you are only preaching to the choir. What's the point?

There are various points. One is that the choir is a lot bigger than many people think it is, especially in America. But, again especially in America, it is largely a closet choir, and it desperately needs encouragement to come out. Judging by the thanks I received all over North America, the encouragement that people like Sam Harris, Dan Dennett and I are able to give is greatly appreciated. So is this website, as I heard again and again. My thanks, yet again, to Josh.

A more subtle reason for preaching to the choir is the need to raise consciousness. When the feminists raised our consciousness about sexist pronouns, they would have been preaching to the choir where the more substantive issues of the rights of women and the evils of discrimination against them were concerned. But that decent, liberal choir still needed its consciousness raising with respect to everyday language. However right-on we may have been on the political issues of rights and discrimination, we nevertheless still unconsciously bought into linguistic conventions that made half the human race feel excluded.

There are other linguistic conventions that still need to go the same way as sexist pronouns, and the atheist choir is not exempt. We all need our consciousness raised. Atheists as well as theists unconsciously buy into our society's convention that religion has uniquely privileged status. I've already mentioned the convention that we must be especially polite and respectful to a person's faith. And I never tire of drawing attention to society's tacit acceptance that it is right to label small children with the religious opinions of their parents.

That's consciousness-raising, and atheists need it just as much as anybody else because atheists, too, have been lulled into overlooking the anomaly: religious opinion is the one kind of parental opinion that – by almost universal consent – can be battened upon children who are, in truth, too young to know what their opinion really is.

5. I'm an atheist, but I wish to dissociate myself from your intemperately strong language.

Sam Harris and I have both received criticism of this kind, and Nick Humphrey probably has too, for the quotation given above. Yet if you look at the language we employ, it is no more strong or intemperate than anybody would use if criticizing a political or economic point of view: no stronger or more intemperate than any theatre critic, art critic or book critic when writing a negative review. Our language sounds strong and intemperate only because of the same weird convention I have already mentioned, that religious faith is uniquely privileged: above and beyond criticism. On pages 20-21 of The God Delusion I gave a wonderful quote from Douglas Adams on the subject.

Book critics or theatre critics can be derisively negative and earn delighted praise for the trenchant wit of their review. A politician may attack an opponent scathingly across the floor of the House and earn plaudits for his robust pugnacity. But let a critic of religion employ a fraction of the same direct forthrightness, and polite society will purse its lips and shake its head: even secular polite society, and especially that part of secular society that loves to announce, "I'm an atheist, BUT . . ."