A little while ago, a comment appeared on one of my threads ... I thought the tone was a little hostile ... appearing to suggest, rather abruptly, that the changes made in the Roman Mass by Pope Paul VI were no more remarkable that those made earlier by other popes. Then the writer hurled at me the Filioque and, in what I take to be irony, said that he supposed this was all right by me because the change was made by the papacy.
I felt that I didn't quite know where to start with all that. In the first place: the popes did not introduce the Creed into the Mass. It seems (Jungmann [ET] Vol II p 469) to have entered the Western Mass in Gaul in the 790s. Its introduction may have been a response to the Adoptianism of some Spanish bishops. Rome herself did not reluctantly follow Charlemagne's initiative for another couple of centuries.
But, so far, my brief and summary narrative has not got to the filioque. So: how did the filioque spread itself around? Not as a Papal initiative. There is an interesting paper by A Breen (Proceedings of the Royal Irish Academy 90c, 107-21) discussing the text of the Creed in an Irish Altar Book known as the Stowe Missal (once owned by the Dukes of Buckingham at Stowe). That book seems to have been scribed in the 790s, when it contained a text of the creed without filioque. But what makes this Missal so fascinating is the way it was subsequently added to and changed by different people. Sometimes somebody would even take a knife to the vellum and scrape portions of text away and then, in smaller handwriting, repeat what he had just scraped away but with additional material ... but he might then discover that he still didn't have all the room he needed so he would bind in a small additional sheet of vellum. (In the first millennium, perhaps the first task of a liturgical reviser was to catch his calf ...) That is the context in which filioque entered the Mass in one Irish monastic site.
Here in the Stowe Missal we have organic evolution of the Liturgy physically on display before our very eyes (if we can get to look at it in Dublin*). In the hands of the presbyters of the worshipping community which actually used the book, it gradually accommodated itself to the changing needs of its church or to the changing fashions within the wider Church. Nobody made massive alterations overnight, whether on his own authority or at the behest of Superior Authority. Nothing could be more unlike what Vatican committeemen did in the 1960s.
As I remarked, Stowe had the Creed, and without filioque. But, as Breen demonstrates, only a few years after the production of Stowe, somebody made some corrections to its text of the Creed, one of which was the addition of filioque above the line. And the text of the Creed which the corrector used to make his corrections was one which had just been promulgated at the 796/7 Council of Foroiulianum. This text had been composed by S Paulinus II, Patriarch of Aquileia (an influential see which used to be so powerful that it wasn't always content to be obediently in communion with Rome). Not a whisker here of the actions of some pope or, for that matter of any external authority. Indeed, when the scribe of Stowe added filioque to his altar book, Patriarch Paulinus, and his Council, and his Emperor, as far as I understand, had no jurisdiction over Ireland. In the centuries before printing, the authority in Liturgy was very generally a combination of Tradition, Sensus Fidelium, and Subsidiarity - with the emphasis very strongly upon the first of this troika.
I suggest, from my consideration of the history of the Stowe Missal, a useful rule of thumb for discerning whether a liturgical change is 'organic' [as the decree Sacrosanctum Concilium of Vatican II mandates] or not. Here goes: If you can continue to use your old Altar Book, while from time to time gumming a new Mass or preface in here or making a marginal alteration there or crossing out this bit or remembering to do that bit differently, then evolution is probably happening organically. If, on the other hand, you have no choice but to abandon that book to gather dust lying useless on the top shelf in your sacristy ... while you go out to the shop and pay big money for a new book ... then the changes are certainly not organic. You've got on your hands, not evolution, but revolution.
I call this the Stowe Test.
* There is a full facsimile in HBS Vol XXXI.