The moment Solomon lost his faith, he was standing on the D train, swaying back and forth with its movement as if in prayer. But it wasn’t a prayer book that the young law student was reading – he had already been to synagogue, where he had wrapped himself in the leather thongs that bound him to Orthodox Judaism, laying phylacteries and reciting the prayers three times daily.

The tome in his hands now was Alan Dershowitz’s The Genesis of Justice (2000), which used Talmudic and Hasidic interpretations of the Bible to argue that stories in the book of Genesis, from Adam and Eve eating the apple to Noah and his ark, constituted God’s learning curve – a means of establishing a moral code and the rules of justice that prevail today.

What struck him about the book was its depth, and a complexity of thought that he had been raised to believe was the exclusive domain of the rabbis whose authority commanded his community of ultra-Orthodox Jews. The book’s brilliance, coupled with its unabashed heresy, created the first of many cracks in Solomon’s faith. Seeing the scriptures interpreted in methods so compelling and yet entirely inconsistent with the dogmas of his youth caused Solomon to question everything he believed to be true.

From Dershowitz, Solomon moved on to evolutionary biology, and then to Stephen Hawking and cosmology, and then biblical criticism, until finally, he was unable to deny the conclusion his newly developed capacity for critical thinking had led him to: he no longer believed in the existence of God.

‘It was the most devastating moment of my life,’ he told me. ‘I wish to this day that I could find the holy grail that proves that I’m wrong, that it’s all true.’

And yet 15 years later, Solomon’s life looks exactly the way it did the day of that fateful train ride, give or take a few infractions. Solomon is still leading the life of an Orthodox Jew. He is married to an Orthodox Jew. His children are Orthodox Jews who go to study the Torah at yeshiva. His parents are ultra-Orthodox Jews. And so, with his new-found atheism, Solomon did nothing.

Solomon is one of hundreds, perhaps thousands, of men and women whose encounters with evolution, science, new atheism and biblical criticism have led them to the conclusion that there is no God, and yet whose social, economic and familial connections to the ultra-Orthodox and Hasidic communities prevent them from giving up the rituals of faith. Those I spoke to could not bring themselves to upend their families and their children’s lives. With too much integrity to believe, they also have too much to leave behind, and so they remain closeted atheists within ultra-Orthodox communities. Names and some places have been changed – every person spoke to me for this story on condition of anonymity. Part of a secret, underground intellectual elite, these people live in fear of being discovered and penalised by an increasingly insular society.

‘Religious fundamentalists want to have a monopoly on truth, a monopoly on morality, but the internet undermines those facades’

But they are also proof of the increasing challenges fundamentalist religious groups face in the age of the internet and a globalised world. With so much information so readily available, such groups can no longer rely on physical and intellectual isolation to maintain their boundaries. In addition to exposing religious adherents to information that challenges the hegemony of their belief systems, the internet gives individuals living in restrictive environments an alternative community.

‘It helps people find others in the same boat,’ said Phil Zuckerman, a professor of sociology at Pitzer College in California who studies apostates and secularism. ‘Twenty, thirty years ago, if you were living in Borough Park, Brooklyn, or Alabama and you were surrounded by Hasids or Pentecostal Christians and you started to have doubts, well, you were alone. Now, you can find someone right away who is in the same boat as you and is also sharing your doubts. You can find community, you can find a connection that bolsters your own situation and gives you support – intellectual and emotional. Religious fundamentalists want to have a monopoly on truth, a monopoly on lifestyle, a monopoly on morality, a monopoly on authority, but the internet undermines all those facades.’

Yanky cut an incongruous figure. A tall ultra-Orthodox man with a short, scruffy beard and short side-locks wrapped behind his ears, wearing traditional Hasidic black-and-white garb, he was sitting on a barstool in an out-of-the-way dive bar in South Brooklyn on a Monday afternoon, sipping a Corona. But Yanky is an incongruous man. Like Solomon, he lives in an Orthodox neighbourhood, has many children who attend yeshivas, goes to synagogue to pray, hosts meals on Sabbath. His life, like the life of any Orthodox Jew, is punctuated a hundred times a day by the small demands the religion makes on its adherents’ lifestyle, demands on what they can eat, what they can wear, where they can go, what they can read, whom they can speak to, what they can touch, when they can touch it, and how often.

Somewhat tragically for a person so occupied, Yanky doesn’t believe in God.

Things didn’t start out that way. Yanky, who has a gentle, defeated air about him, and a shy, cynical sense of humour, was among the most fervent scholars of his cohort. ‘It’s hard to describe how earnest a person I was before,’ he told me. He had spent many years studying the Torah in the most prestigious yeshivas. ‘I had really suffered to be there,’ he said, by way of explaining how much it had meant to him and how deeply invested in the holy texts he once was. He even worked as a rabbi on the side, answering questions pertaining to religious law for lay people in his community.

But Yanky had always had philosophical questions, even as a child. At some point, all of the questions added up, coming to a head when his rabbi asked him to study with a man who had recently become observant. This newly religious man needed a study partner to take him through the religious answers to scientific questions. While able to answer the man’s religious queries, the partnership forced Yanky to think deeply about the issues he had been avoiding, such as the conflicts between the Bible’s claims and those made by science. He tried to put an end to their study sessions, but his rabbi was confident in his ability to stay the course. ‘No, no, it’ll be fine, it’ll be fine,’ Yanky remembers his rabbi telling him.

‘It wasn’t fine.’

That’s when his newly observant study partner took Yanky to a presentation by the British scientist and New Atheist Richard Dawkins, author of The God Delusion (2006). ‘It wasn’t so much that Dawkins was so convincing, or interesting even,’ Yanky told me between short sips of beer. ‘It was just, I was sitting there with this whole group of people who were having this one viewpoint.’ He experienced for the first time what religion looked like from the outside, a series of often ridiculous and always questionable ideas shattering its absolute hold on his psyche.

And something else crystalised at that Dawkins talk: Yanky had at that point hundreds of questions which no one had ever been able to answer to his satisfaction, ranging from scientific questions about the veracity of the Old Testament’s narrative (‘woman very clearly wasn’t taken from man’; ‘ancient humans were not vegetarians,’ he elaborated) to questions concerning the claims made in the Talmud (‘the laws of cooking on Shabbos and kosher cooking laws don’t match up with thermodynamics’; ‘bugs don’t spontaneously generate from plants’). It felt like there was a separate, unsatisfying answer for every burning question. And as Dawkins spoke, Yanky realised that there was one answer that took care of all of his questions – God did not write the Torah because He does not exist. ‘So that was basically it for me,’ he said.

he was an atheist forced to stay under wraps lest his boss fire him, his wife divorce him, and his children get thrown out of school

Yanky was devastated by his realisation that there is no God. ‘It was very upsetting,’ he said, talking quickly. ‘I remember laying in bed and feeling like the world had come to an end. It wasn’t a relief. It was very painful.’

He was so upset that his first move after this realisation was to search out the smartest and most learned rabbis, hoping that they would have answers for him and be able to convince him that he was wrong – that there is a God, that the Torah is true. He wrote anonymous letters to a few respected rabbis, and posted them snail-mail (though this was 2000, he had little to no contact with the internet, as the most pious Jews don’t). The letters contained his questions, mostly culled from the contradictions between the first chapters of the Old Testament and evolutionary theory: evolution suggests that snakes, descended from lizards, lost their legs long before humans evolved – but Genesis states that they lost them after an encounter with man. The Adam and Eve story suggests that humans were created instantaneously, in a single day a mere 6,000 years ago – yet science reveals the slow evolution of human life on Earth, describing the gradual rise of our hominid predecessors over many millions of years.

The explanations he got from rabbinic scholars were weak and obscure. One rabbi sent him a bizarre note, including a story about sitting in a boat, ‘an elaborate allegory intending to describe how we only coast along over the deep waters of the Torah,’ Yanky recalled. ‘It was cool, but it didn’t help me. Thanks Rabbi.’ With nowhere left to turn, he was finally forced to admit what he was: an atheist leading a double life, forced to stay under wraps lest his boss fire him, his wife divorce him, and his children get thrown out of school.

They call themselves ‘Orthoprax’ – those of correct practice – to distinguish themselves from the Orthodox – those of correct belief. Every time I met one, they would introduce me to a few of their friends, though many refused to speak for fear of being discovered. There are far fewer women in this situation than men, and the women were even harder to draw out. They risk losing their children, especially in New York State, where custody is often given to the more religious parent.

Yet things have changed: once so isolated in their atheism, double-lifers passing for Orthodox, ultra-Orthodox and Yeshivish (known for devouring the Talmud) all gather online in chat rooms. I met undercover atheists from many different Hasidic sects – Satmar, Skver, Bobov – where the focus is mystical. They live in Williamsburg, Long Island, New Skver, Jerusalem. Wherever there is an insular Jewish enclave, there are individuals who have come to the conclusion that God does not exist, and yet they maintain their religious cover for social, familial and economic reasons. Many are well-established in their communities, even leaders. Many are financially successful, family men and women, moral people. ‘I am your neighbour with kids in your children’s class,’ wrote one undercover atheist anonymously on a blog. ‘I am one of the weekly sponsors of the Kiddush club… I was your counselor in camp… I do not believe in God.’

The Orthodox community has grown exponentially in the past 50 years. Ultra-Orthodox and Hasidic enclaves such as Lakewood in New Jersey and Kiryas Joel in Upstate New York have the lowest median ages in the entire United States due to their high birthrate. It is normal for families to have anywhere from five to 12 children.

‘We’re talking about a ghetto that’s locked from the inside’

These communities are organised around religion, explains Samuel Heilman, a sociologist at Queens College in New York, who studies contemporary Orthodox Jewish movements. As the population has expanded, so have attempts to keep members in line. But it has been a losing battle, overall. ‘As a sociological principle, one size can never fit all,’ he told me, ‘and the larger the community, the more difficult it is to control.’

That hasn’t stopped efforts. One method of control is limiting secular education for children in subjects such as mathematics and even English. The lack of skills necessary to navigate the outside world can be crippling to most who consider leaving their communities. Another strategy is turning everyone else into an enemy. The tactic is hardly unique. ‘Every fundamentalist group demonises the other – they tend to be very dualist; you’re either with us or without us.’ In the case of the ultra-Orthodox, ‘We’re talking about a ghetto that’s locked from the inside,’ Heilman said. You have to create a threat from the outside to keep those doors locked.

But even for those such as Solomon and Yanky who were educated enough to pursue outside professions, their own psychological states work just as well as any external rules to keep them put. The self-policing mechanism kicked in most strongly through the matchmaking apparatus, the place where status is determined in these communities. A person leaving the community puts a blight on their entire family, stigmatising parents, siblings, children, and even cousins, limiting their ability to marry into ‘good’ families with no such stain.

Are double-lifer’s a danger to the fold? It depends on your point of view.

‘For every one of them, there’s five kids, 10 kids born,’ Heilman said.

‘We have 10,000 kids in school in Williamsburg alone. The majority will stay where they are,’ said a Satmar friend – a believer – in agreement.

‘I could pick off a person a day if I wanted to,’ countered an undercover atheist I’ll call Moishe.

If anything, the double-lifers are more like ‘agent provocateurs inside a besieged system’, Heilman contends. They know what’s real and what’s not real. They know how to game the system. And they have their own signals. Surely it’s only a matter of time before they begin to share their ideas with those who are still believers.

I’m sitting with Moishe, a scholarly luminary in the ultra-Orthodox world, in Solomon’s office in Manhattan; the two are colleagues and confidantes. Moishe is Hasidic, wears a graying beard, lives in the bosom of a Hasidic sect in Brooklyn and has many children. He has written books of exegesis that are studied in many yeshivas, uncovering the hidden secrets of the Torah.

Solomon, too, lives in Brooklyn, has a wife and a bunch of children, and a good job. He is clean-shaven, wears a suit to work and a black velvet yarmulke. Though both are staunch atheists, neither Moishe nor Solomon has any intention of leaving the Orthodox world.

But the similarities end there – Solomon is deeply emotional, the kind of man whose obvious kindness comes from bearing the weight of the world on his shoulders. He is still dogged by the emotional loss of faith. ‘I have an emotional bond to a God that I know does not exist,’ as he puts it.

Moishe, on the other hand, is driven only by the pursuit of truth, with that almost childlike quality that geniuses display during discovery, and a sense of humour wide enough to encompass all of his own foibles. Solomon suffers from intense guilt; the psychological toll of leading a double life weighs heavily on him. ‘I used to be tormented by doubt,’ he said. ‘But now I’m tormented by certainty.’ Moishe can’t understand these feelings. He experienced his new-found intellectual freedom with the joy that comes from liberation.

Moishe is still publicly Hasidic. He wears a shtreimel – the traditional fur hat – on Sabbath. At one point, the Hasidic rabbi leading his sect asked him to become even more religious, referred to as ‘going right’.

‘At that time I was like, what do you mean more right? I’m already at the end! What’s north of the North Pole? But he knew what he was talking about.’ Moishe’s journey from believer to atheist happened in a matter of weeks, after a few passages from Maimonides convinced him that the greatest Jewish scholar was, like himself, an undercover atheist.

Moishe explained: on the one hand, Maimonides felt that the belief that the earth was eternal could be destructive to the Jewish religion. On the other hand, he also said that if the infinite character of the earth could be proven, he would accept it as true. Moishe’s conclusion? Maimonides ‘knew the first part of the Torah was iffy at best and bunk at worst’. Moreover, Maimonides’ attempts to reconcile what he thought was true with what he claimed was true were, in Moishe’s words, an ‘epic fail’.

the greatest tragedy for undercover atheists is the barrier it erects between them and their loved ones

‘Nothing he said made any actual sense,’ he explained. ‘So I was left with one option and one option only: he was an atheist but was hiding it. There, now that made sense. So now I look at myself as a reincarnation of Rambam [Maimonides]. I’m an atheist in hiding just like he was.’

Still, despite his confidence that he could convert a person a day to atheism should he so desire, Moishe balked at the consequences. Perhaps the greatest tragedy for undercover atheists is the barrier it necessarily erects between them and their loved ones.

‘I’m desperate to tell my kids the truth,’ Moishe confessed. And yet, he doesn’t dare. Moishe is not alone. Many I spoke to stay inside the confines of their Orthodox lives for fear of harming their children, opting instead to let them continue to believe what they themselves now consider to be fairy tales.

‘To me, lying to my children was the worst part,’ said another undercover atheist – I’ll call him Yisroel. Yisroel has a very good job – he makes in the high six figures – and is very attached to his wife and children, the opposite of the stereotype that prevails in religious communities surrounding those who lose the faith, namely that they are ‘liars who want to do drugs, cheat on their wives and eat cheeseburgers’, as he put it. Yisroel’s greatest wish is that his children will learn to think critically and figure things out for themselves. But he has no plans to accelerate that process. ‘I take it one day at a time; I don’t have any long-term goal about that,’ he told me when we met in a Manhattan deli on a rainy afternoon.

Every person I spoke to had a different relationship with his spouse on the subject of belief. Moishe and his wife have an agreement that they will marry off the children before making any changes to their lives, though he doesn’t quite know what change would look like. ‘What am I going to do – move to Kansas?’ he joked.

Yanky felt immense relief after he confessed to his wife – he had felt like he was betraying her. ‘It was making me nuts,’ he said. He told her on Tisha B’Av – a fast day commemorating the destruction of the temple and the end of the Jewish Empire, because, as Yanky put it: ‘It was a good time to suffer, you know? She suffered a lot. She wasn’t too happy. She’s still upset.’ The way he told her was: ‘She hadn’t wanted me to go to the Dawkins talk. And I said: You were right!’

But divorce is not an option – Yanky thinks children should have two parents in the same household. ‘It wouldn’t do good things for them in general, and in the religious world, it would damage them, all that stuff,’ he said. ‘And I don’t think moving them out of the religious world would be helpful for them, if that was even an option, so… that’s basically it.’

A few lucky men convinced their wives of their new-found convictions, giving them a partner in crime. One man I spoke to – Yechiel – who lives in Jerusalem told me it was not as painful for his wife when he convinced her. ‘Women are in a much more minor role in the community,’ he said. ‘Women are expected to express religious devotion by raising the kids, by much more physical things – getting a job, supporting their husband’s learning. Much less a direct spiritual experience, so for her to give it up wasn’t giving up much.’

But it was for him. He remembered the direct aftermath of his loss of faith. ‘I was praying to Hashem [God]: Give me back my belief, prove to me that it’s true, begging and begging. At some point, I realised it’s just plain stupid.’ Still, he said: ‘If you would see me in the street, my white shirt and black yarmulke, you wouldn’t know anything at all.’ His wife is now pushing for more changes to their lifestyle, but fear of hurting his parents keeps Yechiel in line.

One Hasidic woman I will call Fruma lives in the Satmar enclave of Kiryas Joel in New York State. Fruma’s husband doesn’t know she has lost her faith. If he found out, he would certainly divorce her and take away her children. The last time she showed signs of non-conformist behaviour, her husband consulted the community leaders. They sent her to see a mental health specialist, who medicated her. ‘The mental illness card has been used often in cases like mine,’ she wrote. She has since seen another mental health specialist; he gave her a clean bill of health.

Fruma lives in constant, crippling fear of her husband finding out her true beliefs, so much so that she refused to meet me, and would communicate her thoughts only via Facebook. The one time we spoke on the phone, she called me from a restricted number. Fruma lost her faith a few years ago, but she found that exercising new freedoms only added to her unhappiness.

‘Lying creates so much inner conflict: breaks down all forms of trust, makes you hate the person involved, but especially makes you hate yourself’

‘At first it felt extremely liberating to finally feel validated,’ she wrote. ‘That I’m not crazy – as some would like me to believe – because I can’t conform and because my thinking is different. After a few months it dawned on me that it’s not all that great. What happened was that those pockets of freedom where I got away for a bit contrasted too sharply to my daily existence, and made the staying so much harder. The feeling that I need to leave was very strong.’

Though Fruma never had a happy marriage, the toll that dishonesty is taking on her is immense. ‘Lying creates so much inner conflict,’ she wrote. ‘Breaks down all forms of trust, makes you hate the person involved, but especially makes you hate yourself.’

After Yisroel, the Manhattan high-earner, told his wife that he no longer believed in God, she was devastated. When he suggested coming out, she threatened to divorce him, ‘a non-starter’, in Yisroel’s words. She felt it would be too confusing to the children, and Yisroel more or less agreed. So, to save his marriage, Yisroel vowed to his wife never to break any of the religious laws, and he never has. And to mitigate his wife’s hopes that he might one day rediscover his belief in God, Yisroel buys a lottery ticket every week, ‘just to keep that door open. I buy the ticket, just for her, and I say: Please Hashem, let me win.’

It’s not all bad. Solomon, who lost his faith on the D train, says there’s a lot of good in the Orthodox community to ameliorate the psychological toll of living a double life, such as ‘the focus on family, the fact that I’m probably not going to have to worry that my daughter’s getting pregnant or stoned at 16. There’s a lot of good, even if none of it’s true. I think it’s a nice life.’

Yisroel calls it ‘performance art’. ‘To a certain extent everyone leads a secret life, showing different sides to different people,’ he said.

Do the undercover atheists herald the end of ultra-Orthodoxy, or only a new, more insulated and controlled beginning? Here, Solomon and Moishe disagree.

As long as ultra-Orthodox communities continue to marry people off at such young ages, doubters will remain stuck, Solomon contends. ‘Religion has survived a lot of major challenges,’ he said, and the recent turn towards fundamentalism within ultra-Orthodox Jewish communities is just that – a coping mechanism to weed out the non-conformists. ‘The radicalisation of ultra-Orthodox Judaism is a sign of its success, not its failure.’

But Moishe believes that the phenomenon of atheism is deeply entrenched in the Orthodox way of life. ‘Everybody’s faking,’ he insisted. ‘I think it’s all going to come crashing down. I say 20 years.’