Were a 12th-century magister at the then centre of learning in the Western world — the university of Paris — to apply the exciting, frightening “New Learning” of Aristotle to Howard Brenton’s In Extremis, a retelling of the much-explored story of the lovers Abelard and Heloise that had its world premiere at Shakespeare’s Globe tonight, he might give it two marks out of three.

There’s a brilliant “antithesis” in the philosophical and political conflict between the adventurous rationalism of the young Peter Abelard and the traditional mysticist of the would-be saint Bernard of Clairvaux. And the synthesis of the whole play – its masterly interweaving of comedy and drama – deserves full marks. Brenton draws unashamedly on the traditions of the Elizabethans, who learnt to “work” a socially mixed crowd in the intimate, fast-moving space of coaching inn, and the brilliance of Shakespeare, who brought the new learning of his own time into the mix.

Who’d have thought that a 21st-century crowd could be listening so intently to philosophical debate from the 12th-century about the nature of the ideal that a solitary ringtone would sound like a thunderclap? When Colin Hurley, who’s spot-on as the knowing, cynical, clever Louis VI, says: “Theology in Paris these days is more interesting than wrestling” there’s no hint of irony, only a laugh of acknowledgement.

Yet it is in the thesis — the love affair between Abelard and Heloise, the part of the story that everyone knows — that Brenton’s play falls down. Little blame can be laid on the actors: there’s a clear, almost palpable, chemistry between Oliver Boot’s Aberlard and Sally Bretton’s Heloise.

The problem lies, it seems to me, in the writing of the character of Heloise. Going back to the original story, in his Historia calamitatum Abelard made clear that as well as falling under the spell of hormones, he had been stunned by the literary genius of Heloise. And it is evident, even from her early letters, that the real-life Heloise was formulating an ethical theory of love that was deeply philosophical.

But despite Brenton having borrowed some of Heloise’s own words for his character — “sweeter for me will always be the word mistess” — the woman given us here for most of the play, by Brenton and director John Dove, is a thoroughly modern miss interested in only in the philosophy of a good lay. It is yet one more twist on the old “man as mind, woman as body” division.

Finally, in the climactic confrontation between Heloise and Bernard she’s allowed to flower, her mind really allowed to show more – to show her truly revolutionary radicalism — yet in the end this is lost in an oh-so-clever, but much too smart-arse final line.

There’s a disappointment in that which perhaps makes me sound harsher than I intend, for this is an excellent production and play that just fails to make the leap to superb. The confrontations between Abelard and Bernard will linger long in the memory, and not just because their arguments between reason and religious passion having frighteningly modern echoes.

At times Jack Laskey’s Bernard is too frenetic, too frenzied, to be believable, but on balance he a fine mix of the calculating and the possessed. (And if he occasionally looks all too much like Tony Blair on one of his more messianic missions, I’m sure that’s purely coincidence.)

In this conflict Brenton’s writing too is nicely balanced, for Abelard is no whiter-than-white goody-two-shoes. He’s an ambitious, often arrogant, impetuous young man, glorying in the power of his mind and its ability to run rings around all he encounters. You want him to win in his battle with the exploitative Bernard, but you’re not altogether sorry that he’s brought down to earth with a thump.

Brenton, Dove and the cast manage a fine job with many of the minor characters. Pascale Burgess as Abelard’s sister Denise, the sensible, practically intelligent member of the family, is outstanding, and Fred Ridgeway’s Fulbert – Heloise’s silly but proud, loving but hurt, guardian – avoids descending too far into pathos. The frequent comic scenes are masterfully handled – the beautifully timed toppling of a drunken bishop into minutes-long undignified immobility and the stomach-turning display of Bernard’s saintly party piece, the licking of rotting feet –are just two examples of classic Globe stagecraft.

There’s much here to justify artistic director Dominic Dromgoole’s decision to incorporate new writing into his first Globe season. Yet in both of the new plays we’ve seen two male writers exploring what have turned out to be two male-centred stories. It might be nice to see another view next year – perhaps even a female writer allowing Heloise to flower intellectually, not just physically, in a more nuanced space.

The production continues in rep until October 7 at Shakespeare’s Globe, with online booking. Elsewhere: A profile of the playwright; a discussion of the letters; Abelard’s Historia Calamitatum on Poject Gutenberg.