MY former Herald colleague Alan Morrison talks of the drive for everyone involved in the music industry in Scotland to be “singing from the same hymn sheet”, elsewhere in today's Herald. That same adage might as easily be applied to the women – and it has been almost exclusively women thus far – who have been taking the time to talk to me (and many other folk) about what will be on offer at the vast cultural jamboree that is the Edinburgh Festival Fringe.

Each year we critics search for themes that permeate the world’s largest festival, believing that an open-access, non-curated event will surely speak profound truths if its concerns turn out to coalesce, chiming resonantly with the zeitgeist of our troubled age.

Most of the time, that investigation proves fairly fruitless, whatever many articles over the years may have insisted to the contrary. An essential part of the charm of the Fringe is its diversity. When 60 countries bring over 3000 shows to 300 venues in three weeks, you would hope and trust that few of them will have a huge amount in common.

This year, however, I think things may genuinely and observably be a bit different.

The gloss that accompanied the publication of the 450-page Fringe brochure noted exactly the same common threads that I had already been unpicking in the reams of press releases and emails piling up on my desk as arts PR teams make their annual spring pilgrimage north to tell people like me what they are hoping we will write about in August.

In terms of personal and global politics this is going to be a Fringe with a great deal to say. Shona McCarthy, chief executive of the Fringe Society, talked of celebrating 70 years of championing artistic freedom and providing a platform for life-affirming work.

The Fringe’s 70th anniversary slogan is The Alliance of Defiance, and when McCarthy talks of Fringe artists being able to express themselves “without fear of censorship”, it seems more significant than ever that Edinburgh is able to operate in a way that many of the artists may envy greatly by comparison with the situation in their home countries.

On the previous day, the artistic director of the Traverse, Orla O’Loughlin, had unveiled a bumper programme of work for the Fringe at Scotland’s new writing theatre by talking of heading a fight against “the divisive, the constrictive and the unjust.”

Check out the work there, whether in partnership with the International Festival and the National Theatre of Scotland as well as self-produced, or in the theatre’s role as a welcoming home for bold visiting companies, and you will find a rich seam of politically-charged work that seems certain to maintain the Cambridge Street venue’s position as one of the busiest destinations in August. O’Loughlin ended her presentation by quoting the late John Berger that the arts must not exist in a “liberal bubble” but be a “pocket of resistance”.

The Traverse is not operating in any sort of bubble during the Fringe. Work across a whole range of venues can be found exploring issues of physical and mental health and disability, with women having a noticeably strong voice this year, so questions of fertility are particularly explored.

Immigration and cultural identity are also hot topics and the question of gender is explored from more perspectives than many people in the potential audience will perhaps ever have considered. If you were to try to define and embrace the impetus behind this drive to explore the most challenging issues among the current generation of theatre-makers and performers, it could most simply be construed as a response to a perceived threat to the diversity displayed by the human animal across the globe. And diversity is, of course, definitively what the Fringe is all about.

Besides the thoughtful analysis of the work being presented from women such as McCarthy and O’Loughlin, the launch of the Fringe brochure is always accompanied by statistics like the ones I used above, but also even larger numbers: of tickets for sale, bed-nights available in Edinburgh and pounds sterling benefit to the Scottish economy.

These things are important, both in the inexorable growth of the Fringe as an unstoppable cultural phenomenon, and for its sustainability for a quite remarkable 70 years. But if it didn’t have something to say that people felt compelled to listen to, none of those sums would add up at all.