Despite such strong transcendent themes pulsing the worlds of the four twentieth-century women from different time-zones who occupy McLean's play, she had never considered it for a title. Only when the writer's son asked her what the new work was about did it become obvious.
"I said it was about sex and God, but didn't have a title," McLean explains, "and he said 'That's it!'"
McLean's work is full of little eureka moments like this, in which characters in seemingly domestic situations are enlightened somehow.
While you could say this about most drama, over the last decade or so McLean has quietly become one of the most experimental playwrights in the country. Her subversion of dramatic form has been subtle, however, whether in the rain-battered trip to Iona taken in Shimmer in 2004, in the exploration of family in Word For Word, her first collaboration with Magnetic North the year before, or her exploration of urban ennui in 2010's Any Given Day.
If elements of all these plays border on a home-grown form of magical realism, McLean's narratives are rooted in the surface ordinariness of the everyday. Only after bearing witness to them does one realise just how tantalisingly special they are. Sex and God may follow in this tradition, but, as the quartet of stories are told simultaneously, it also finds McLean stretching her writing muscles further out than ever before.
"I had a conversation with someone about how there hadn't been a history of the twentieth century in the west coast of Scotland either written by or about women," McLean says about the roots of the new play.
"That coincided with me researching into my personal family history, and then someone asked if I had an idea for TV. I explained all of this, but couldn't find a way of doing it in the sort of straightforward way that you have to do things for TV. You know me, I'm never happy unless I'm juggling with form."
The result, according to McLean, is not unrelated to the work she explored as creative fellow at Edinburgh University's Institute of Advanced Studies in Humanities between 2010 and 2011.
"What happens if you remove the chronology of a story?" she asks. "What are you then seeing? That suddenly opened me up to being much more playful with form, and I was able to put all four women in the same place. The things that emerged out of this, which were lots of sex and lots of God, seemed to have a big impact on all this. Those two things jumped out as aspects of life which, if you look through the twentieth century, are things that seem to matter."
Each of the women in Sex and God occupies a moment somewhere between the beginning and the end of the twentieth century. "There's no specific dates," McLean points out. "It's funny, because when you abstract them, these things don't matter. Sometimes it's as if they do know each other, then at other times it's as if they don't."
Central to McLean's creative process has been the influence of Cold Dark Matter: An Exploded View, an installation by visual artist Cornelia Parker. Parker's piece suspends time via the shattered particles of an exploded shed frozen in mid-blast.
"It was a big influence on the form," McLean admits. "The stories are told in a very fragmented fashion, and each one of the four voices occupied equal amounts of space in my head.
"In that way, you're never going to know the whole of these women's stories, the same as you're never going to see the whole of this exploded shed. You'll only see parts of their stories that they choose to reveal."
In this respect, McLean is keen to stress that amongst the maelstrom of desire, loss, relationships and family driving her play, Sex and God is most definitely not a series of criss-crossing monologues. Rather, the effect sounds more akin to a musical score or a liturgy.
"It would have been impossible to write this play as monologues," she says. "Magnetic North are the kind of company who embrace experimenting with form, so I knew I could go to Nick with something like this, and that he would relish it."
At one point in rehearsals, Bone put every word spoken in Sex and God onto one long sheet of paper, so it really did more resemble a musical score than a script.
"I suppose it also became impossible to write these stories and have any kind of judgment about whether I found what these women were doing was right or wrong, but moving backwards through the twentieth century, I also found this great warmth."
There's always been a keen sense of spirituality filtering through McLean's work, and with Sex and God it sounds more pronounced than ever.
"That's a consequence of how I've experienced the world," McLean says.
"It's very hard to grow up in a world without some sort of sense of spirituality, and that's directly related to the sort of questioning we do from a very early age about what is the nature of being alive in the world."
Despite what sounds like Sex and God's clear leaning towards transcendent forces, there remains something very grounded in McLean's work.
"Here's what I'm hoping," says McLean. "I'm hoping that there's humanity in the play. The heart in it. The people in it. That's what I hope people will really love, and that they're not obscured by any other kind of storytelling. It's just these four women, each one of them in the moment."
Sex and God, Platform, Easterhouse, September 27-28, then tours