Why does Islam always need to be defended?

S: Is it okay to meet you by myself?

Me: If you like. Is your wife busy?

S: Yes.

Me: Of course. Please give her my regards.

S: Does it bother u... meeting u (sic) alone?

Me: No, why should it?

S: I don't know.

It occurred to me later that for him to ask these questions wasn't simply a part of that annoying habit men have of frustrating my quest to form platonic friendships with them. "S" comes from a society where the sexes are strictly segregated, so that the issue of whether I would meet a man alone actually merits a query.

A couple of hours later, as I allayed the perpetual guilt of a (wannabe) writer's life by using my laptop as a table ornament at a cafe, S walks up. He's cashmere clad and very Sloaney, I'm bushy-haired from a post workout shower.

I had met S twice before: first at another café where, forced to overcome the Londoner's horror of sharing a table, I had spilled coffee over myself. Without an exchange of words, he had asked his wife to hand me some paper napkins from her bag. Their kindness moved me.

They asked me where I was from - they had been discussing me while I was engrossed in my podcast, and S felt vindicated that I did indeed come from India. His English was competent, of the kind that makes me mind my own, making sure that it did not become too idiomatic. I learned that they were from a wealthy builder family in Saudi Arabia, here for the summer with their family, that they were my neighbours, had breakfast at this café every day, and that S owned another apartment in a famous skyscraper next to the river.

My life was strange and inexplicable to them: I was unmarried, lived alone and they could not figure out what I did for a living. "Museum" and "curator" were both strange concepts, but "writer", though inaccurate, was at least more familiar, so I became one.

I tried to engage S's wife in conversation, but she was shy and although her English was better than my Arabic, she had gotten, like many married women across cultures, into the habit of letting her husband speak for her.

I met them again a week later on a lazy summer afternoon in Hyde Park, when the deck chairs are replete with women in burqas. My friend and I had been doing yoga in the park, and S asked me whether yoga was a Hindu practice. My Italian friend, a Catholic and a far more competent yogini than myself answered. She said yoga was an inherently spiritual practice, but not a prescriptive one - that downward dog wouldn't turn his wife into an idolater overnight. My friend was horrified to learn that S and his wife were cousins. Her horror provided a perverse amusement to the lazy, cynical inaction that now marks my interaction with the world. I used to mistake it for a wise tolerance, a sought after ataraxia; I realise now that it is a hideous and smug laziness.

This interaction happened last year, when Israel was bombing Gaza, and my friend had led a Facebook campaign against the cruelty to the Palestininan kids. Perhaps she expected a more urgent and impassioned engagement with the issue from S. For her, as for me, his Arabness, undifferentiated and perfect, formed in our imagination from second hand accounts, was his primary distinguishing quality. S was not an individual; he was his race. I have many friends from the Middle East, and many of them identify themselves as Arabs. Yet, because I know them individually, I do not think of them in terms of their race. But clearly, this did not mean that my world view wasn't formed through the lens of a stereotype. It was merely made more smug by hypocrisy.

And so, as S seemed as disengaged with the issue as the rest of the world, somehow contrary to his racial destiny, this left my friend in a simmering frustration of unshared sentiment.

Meanwhile, I had tried to establish that S's wife was a persecuted woman, commensurate with my liberal world view of women in the Arab world. However, despite the hijab, she wasn't at all downtrodden. Annoyingly, she seemed infinitely happier and more tranquil than the emancipated women who were quizzing her.

In an effort to unsettle her convictions, I explained to her how it would be ideal if people could look past gender to interact with people, not sexes. "But men are not like that," she said pityingly, astonished at my idiocy. Her certainty was frustrating, but perhaps more accurate than my feeble hopes for rejigging a million years of evolution.

But now, without his wife, S was more assertive. We discussed Bahrain and the Saudi support of the minority Sunni regime; he was convinced I had a Shia friend who had fed me propaganda, because I didn't immediately denounce the Shias and their prophets. He told me the Islamic State (ISIS) was a NATO (North Atlantic Treaty Organisation) invention so that all terrorists "could be gathered in one place and bombed out of existence". And then, without a preamble: "What is your idea of Islam? Tell me what aspect you have a problem with."

I became aware of the infinite weight of a religion that constantly needs to be explained to the rest of the world. It cannot be a happy burden. "I don't," I said. "As long as a religion does not impose its edicts on others, I have no problem with it."

He looked deflated: it seemed the defence of Islam had become the principal component of his conversations with non-Muslims.

All this while groups of young Arab males were trooping up and down the pavement, eyeing up groups of Arab women who tried to appear oblivious of their scrutiny. I asked S why they ranged in separate tribes - why they did not just talk to each other. "They have their ways," he said. "We don't like it, but they find a way to meet," he sniggered.

I asked him why interaction between the sexes was a problem, and if so many young people wanted to do it, and succeeded, surely it was less hypocritical to modify social norms that no longer fit the needs of the populace? Why, for instance, did Saudi Arabia still practise strict segregation and did not allow women to drive?

He thought women would be driving very soon in Saudi Arabia - the only country in the Middle East where the restriction still applied. Regarding restriction in dress, he was more adamant: he felt men looked at women in certain ways, and that hair and eyes held sexual allure and, therefore, should be covered.

Looking at him, I suddenly felt naked, aware of my hair and eyes in a way that I had not been before. It was as if I was looking at myself through his eyes, and it was uncomfortable to be so utterly sexualised.

Then a Ferrari roared into life beside us as a stripling youth got behind the wheel and drowned out conversation.

"Do you like it?" S asked.

"Yes," I said. "All credit to the designers and engineers. Not to the boy whose daddy bought it for him."

I don't know why I said that. Perhaps to emphasise that my interaction with him wasn't transactional.

Would he mind, I asked, if his wife met another man in the same way I was meeting him?

"Why would she want to? Women want different things than men: home, comfort, love and attention. I give her all these things, so why should she need to meet anyone outside?"

Just as I had no idea about him beyond a dated caricature, he had no idea of women except the limited glimpses his wife, and through the lens his culture allowed him. He thought of women, not as inferior, but as a nobler, and therefore, much more limited species. I wanted to tell him that I was unresolved, contradictory, sexual, noble, fallen, and most of all, curious. In fact, in many ways, just like him: except I didn't think that looking at a man's hair, eyes, or any other body part would send me into an uncontrollable frenzy of lust. I considered the gap of gender, culture, language and religion between us, and suddenly it felt insurmountable. Once again, I was drowning in a hopeless solipsism.

It was disconcerting to face his certainties of faith and belief, and compare them to my own faith of hypotheses - fragile, feeble, friable and uncertain - which often gave me so little satisfaction. I could see, not for the first time, the dangerous allure of a prescriptive, certain, faith of prophets, books and commandments.

I have a faith too: of personal enquiry, uncertainty, exploration, where the only edict is to conquer ignorance. It is a hard faith, and perhaps meant for people less stupid than me.

I realised then that it wasn't my inherent logic, rationality or superior mental faculties that allowed to me to consider S and his faith with equanimity with no wish to make him change his mind or agree with me... It was the intransigent prescription of my tolerant faith. My difficult, sprawling, handbook-less faith that allowed me to be tolerant, just as S's easy faith disallowed him from extending me that same tolerance. Perhaps tolerance is just another name for laziness, because for so few is it an intellectual conclusion, arrived at after a rational debate.

It was a lowering realisation: that we were both bound to the childhood conditioning of our minds, and to our genders. We would always be strangers, conversing only in stereotypes.

And when S sent me pictures of himself in his white thobe with his white Arabian stallion and his white Ferrari, I did not respond. I didn't know how to.