Isn't it enough to see that a garden is beautiful without having to believe that there are fairies at the bottom of it too?

The God of the Old Testament is arguably the most unpleasant character in all fiction: jealous and proud of it; a petty, unjust, unforgiving control-freak; a vindictive, bloodthirsty ethnic cleanser; a misogynistic, homophobic, racist, infanticidal, genocidal, filicidal, pestilential, megalomaniacal, sadomasochistic, capriciously malevolent bully.

Science has taught us, against all evolved intuition, that apparently solid things like crystals and rocks are really composed almost entirely of empty space. The familiar illustration represents the nucleus of an atom as a fly in the middle of a sports stadium. The next atom is right outside the stadium. The hardest, solidest, densest rock, then, is 'really' almost entirely empty space, broken only by tiny particles so far apart that they shouldn't count. So why do rocks look and feel solid and hard and impenetrable?
I won't try to imagine how Wittgenstein might have answered that question. But, as an evolutionary biologist, I would answer it like this. Our brains have evolved to help our bodies find their way around the world on the scale at which those bodies operate. We never evolved to navigate the world of atoms. If we had, our brains probably would perceive rocks as full of empty space. Rocks feel hard and impenetrable to our hands because our hands can't penetrate them. The reason they can't penetrate them is unconnected with the sizes and separations of the particles that constitute matter. Instead, it has to do with the force fields that are associated with those widely spaced particles in 'solid' matter. It is useful for our brains to construct notions like solidity and impenetrability, because such notions help us to navigate our bodies through a world in which objects – which we call solid – cannot occupy the same space as each other.
A little comic relief at this point – from The Men who Stare at Goats by Jon Ronson:

This is a true story. It is the summer of 1983. Major General Albert Stubblebine III is sitting behind his desk in Arlington, Virginia, and he is staring at his wall, upon which hang his numerous military awards. They detail a long and distinguished career. He is the United States Army's chief of intelligence, with sixteen thousand soldiers under his command … He looks past his awards to the wall itself. There is something he feels he must do even though the thought of it frightens him. He thinks about the choice he has to make. He can stay in his office or he can go into the next office … He stands up, moves out from behind his desk, and begins to walk. I mean, he thinks, what is the atom mostly made up of anyway? Space! He quickens his pace. What am I mostly made of? He thinks. Atoms! He is almost at a jog now. What is the wall mostly made up of? He thinks. Atoms! All I have to do is merge the spaces. … Then General Stubblebine bangs his nose hard on the wall of his office. Damn, he thinks. General Stubblebine is confounded by his continual failure to walk through his wall.

I'll end the chapter with a particular case study, which tellingly illuminates society's exaggerated respect for religion, over and above ordinary human respect. The case flared up in February 2006 – a ludicrous episode, which veered wildly between the extremes of comedy and tragedy. The previous September, the Danish newspaper Jyllands-Posten published twelve cartoons depicting the prophet Muhammad. Over the next three months, indignation was carefully and systematically nurtured throughout the Islamic world by a small group of Muslims living in Denmark, led by two imams who had been granted sanctuary there. In late 2005 these malevolent exiles travelled from Denmark to Egypt bearing a dossier, which was copied and circulated from there to the whole Islamic world, including, importantly, Indonesia. The dossier contained falsehoods about alleged maltreatment of Muslims in Denmark, and the tendentious lie that Jyllands-Posten was a government-run newspaper. It also contained the twelve cartoons which, crucially, the imams had supplemented with three additional images whose origin was mysterious but which certainly had no connection with Denmark. Unlike the original twelve, these three add-ons were genuinely offensive – or would have been if they had, as the zealous propagandists alleged, depicted Muhammad. A particularly damaging one of these three was not a cartoon at all but a faxed photograph of a bearded man wearing a fake pig's snout held on with elastic. It has subsequently turned out that this was an Associated Press photograph of a Frenchman entered for a pig-squealing contest at a country fair in France. The photograph had no connection whatsoever with the prophet Muhammad, no connection with Islam, and no connection with Denmark. But the Muslim activists, on their mischief-stirring hike to Cairo, implied all three connections … with predictable results.
The carefully cultivated 'hurt' and 'offence' was brought to an explosive head five months after the twelve cartoons were originally published. Demonstrators in Pakistan and Indonesia burned Danish flags (where did they get them from?) and hysterical demands were made for the Danish government to apologize. (Apologize for what? They didn't draw the cartoons, or publish them. Danes just live in a country with a free press, something that people in many Islamic countries might have a hard time understanding.) Newspapers in Norway, Germany, France and even the United States (but, conspicuously, not Britain) reprinted the cartoons in gestures of solidarity with Jyllands-Posten, which added fuel to the flames. Embassies and consulates were trashed, Danish goods were boycotted, Danish citizens and, indeed, Westerners generally, were physically threatened; Christian churches in Pakistan, with no Danish or European connections at all, were burned. Nine people were killed when Libyan rioters attacked and burned the Italian consulate in Benghazi. As Germaine Greer wrote, what these people really love and do best is pandemonium.
A bounty of $1 million was placed on the head of 'the Danish cartoonist' by a Pakistani imam – who was apparently unaware that there were twelve different Danish cartoonists, and almost certainly unaware that the three most offensive pictures had never appeared in Denmark at all (and, by the way, where was that million going to come from?). In Nigeria, Muslim protesters against the Danish cartoons burned down several Christian churches, and used machetes to attack and kill (black Nigerian) Christians in the streets. One Christian was put inside a rubber tyre, doused with petrol and set alight. Demonstrators were photographed in Britain bearing banners saying 'Slay those who insult Islam', 'Butcher those who mock Islam', 'Europe you will pay: Demolition is on its way' and apparently without irony, 'Behead those who say Islam is a violent religion'.
In the aftermath of all this, the journalist Andrew Mueller interviewed Britain's leading 'moderate' Muslim, Sir Iqbal Sacranie. Moderate he may be by today's Islamic standards, but in Andrew Mueller's account he still stands by the remark he made when Salman Rushdie was condemned to death for writing a novel: 'Death is perhaps too easy for him' - a remark that sets him in ignominious contrast to his courageous predecessor as Britain's most influential Muslim, the late Dr Zaki Badawi, who offered Salman Rushdie sanctuary in his own home. Sacranie told Mueller how concerned he was about the Danish cartoons. Mueller was concerned too, but for a different reason: 'I am concerned that the ridiculous, disproportionate reaction to some unfunny sketches in an obscure Scandinavian newspaper may confirm that … Islam and the west are fundamentally irreconcilable.' Sacranie, on the other hand, praised British newspapers for not reprinting the cartoons, to which Mueller voiced the suspicion of most of the nation that 'the restraint of British newspapers derived less from sensitivity to Muslim discontent than it did from a desire not to have their windows broken'.
Sacranie explained that 'The person of the Prophet, peace be upon him, is revered so profoundly in the Muslim world, with a love and affection that cannot be explained in words. It goes beyond your parents, your loved ones, your children. That is part of the faith. There is also an Islamic teaching that one does not depict the Prophet.' This rather assumes, as Mueller observed,

that the values of Islam trump anyone else's – which is
what any follower of Islam does assume, just as any
follower of any religion believes that theirs is the sole way,
truth and light. If people wish to love a 7th century preacher
more than their own families, that's up to them,
but nobody else is obliged to take it seriously …

Except that if you don't take it seriously and accord it proper respect you are physically threatened, on a scale that no other religion has aspired to since the Middle Ages. One can't help wondering why such violence is necessary, given that, as Mueller notes: 'If any of you clowns are right about anything, the cartoonists are going to hell anyway – won't that do? In the meantime, if you want to get excited about affronts to Muslims, read the Amnesty International reports on Syria and Saudi Arabia.'
Many people have noted the contrast between the hysterical 'hurt' professed by Muslims and the readiness with which Arab media publish stereotypical anti-Jewish cartoons. At a demonstration in Pakistan against the Danish cartoons, a woman in a black burka was photographed carrying a banner reading 'God bless Hitler'.
In response to all this frenzied pandemonium, decent liberal newspapers deplored the violence and made token noises about free speech. But at the same time they expressed 'respect' and 'sympathy' for the deep 'offence' and 'hurt' that Muslims had 'suffered'. The 'hurt' and 'suffering' consisted, remember, not in any person enduring violence or real pain of any kind: nothing more than a few daubs of printing ink in a newspaper that nobody outside Denmark would ever have heard of but for a deliberate campaign of incitement to mayhem.
I am not in favour of offending or hurting anyone just for the sake of it. But I am intrigued and mystified by the disproportionate privileging of religion in our otherwise secular societies. All politicians must get used to disrespectful cartoons of their faces, and nobody riots in their defence. What is so special about religion that we grant it such uniquely privileged respect? As H. L. Mencken said: 'We must respect the other fellow's religion, but only in the sense and to the extent that we respect his theory that his wife is beautiful and his children smart.'
It is in the lights of the unparalleled presumption of respect for religion that I make my own disclaimer for this book. I shall not go out of my way to offend, but or shall I don kid gloves to handle religion any more gently than I would handle anything else.

Fundamentalists know they are right because they have read the truth in a holy book, and they know, in advance, that nothing will budge them from their belief. The truth of the holy book is an axiom, not the end product of a process of reasoning. The book is true, and if the evidence seems to contradict it, it is the evidence that must be thrown out, not the book. By contrast, what I, as a scientist, believe (for example, evolution) I believe not because of reading a holy book but because I have studied the evidence.