A minister doesn't believe in God – and she's still a minister? Surely some mistake.

But Rev Gretta Vosper of the United Church of Canada (UCC) has been a self-declared atheist for years and it's only now that her Church is taking action. It's instituted a review of whether she's being true to her ordination vows, which include affirming a belief in "God: Father, Son, and Holy Spirit". Vosper, who leads the West Hill United Church in Toronto, has attempted to appeal against the review, but her case was rejected by the Church's judicial committee.

There's no doubt that she doesn't believe in God; her blog is subtitled 'Minister, author, atheist'. However, it's not quite as simple as that. She explains that she said in 2001 she didn't believe in a "supernatural, interventionist, divine being" and was a 'non-theist'. Then: "In 2013, I embraced the term 'atheist' which means, literally, no belief in a theistic, supernatural being."

She also refers to being in solidarity with atheists in Bangladesh, murdered for their lack of faith. She's no great fan of the Bible, either: there are horrible judgmental churches (amen to that), but: "As for the nice churches and synagogues and mosques, well, their messages – lovely though they may be – reinforce a divine hand in the documents that underpin hateful, fundamentalist beliefs."

So, it seems, belief in a supernatural being is daft, and worse than that – it validates texts and attitudes that lead to untold harm being done.

For most Christians it looks like an open and shut case, with the only cause for wonder being the delay in the UCC's action against her. Full disclosure: I'm with the majority. I think when someone's personal understanding of God becomes so detached from the Church's consensus, they cease to be 'Christian' in the plain sense of the word. When that person is a minister whose ordination vows commit them to belief in the historic understanding of God, Church and gospel held by Christians for the last couple of thousand years, they are more particularly required to hold them without mental reservations or intellectual gymnastics. If they can't, they should leave. In Vosper's case, she might be able to take her congregation with her; they have been rather supportive, apparently.

On the other hand: she makes the perfectly valid point that the whole question of God's 'existence' is philosophically and theologically more complicated than it looks at first glance. God does not 'exist' in the same way the chair I'm sitting on or the laptop I'm writing this on exists. It's a human category into which he does not fall. She is probably not a fan of Karl Barth, but Barth put it like this: "We must be clear that whatever we say of God in such human concepts can never be more than an indication of Him; no such concept can really conceive the nature of God. God is inconceivable."

Vosper thinks there are lots of clergy who are technically atheists because they don't really believe in a God who interacts with his creation, who is a 'being' that can be known and who revealed himself in Scripture and in Jesus. In a post yesterday she says: "I don't think that there are many clergy trained in the UCC who, if they actually engaged during their studies, came out as classic theists with the understanding of the Bible as God's Word or Jesus as the Son of God who died for our sins. Could be wrong, but if we took a poll and left out the word 'atheist', I think the results would show that most clergy are not theists."

But there's a world of difference between being aware of the subtleties of theological discourse and believing – as Barth did –  that God still chooses to reveal himself to human beings in loving and redemptive acts, and choosing to identify yourself with a tradition that rejects the whole idea of God and focuses purely on humanity.

It's that path that Vosper has taken. Perhaps she should be applauded for her honesty, but it's a pity she is seeking to stretch the boundaries of acceptable theological difference beyond what any Church could accept.

So is she right in believing that traditional religion has just had its day? She told CTV's Canada AM on Monday that people "are not in search of doctrinal beliefs that are dictated by religious organisations, however progressive those beliefs may be articulated". Canada, certainly, is not a particularly religious country. At the same time she still believes the Church – as it's re-invented at West Hill – has something to offer. 

The trouble is that taking leave of God while retaining the trappings of religion is a fundamentally pointless exercise. Religion only means something if its heart still beats; and the heart of religion is belief. Religion without belief is a pastime, on a level with a visit to a museum or a concert; it might interest, it might even move, but it doesn't change or empower. 

The first line of the Apostle's Creed is: "I believe in God." As Barth also pointed out (in Credo, his book of lectures on the Creed) you have to understand exactly what you mean when you say that, but it's the foundation of everything else. 

Follow Mark Woods on Twitter: @RevMarkWoods