Periodically one hears Roman Catholics explain the filioque using their concept of Doctrinal Development. The current position of the Roman Church they argue is that when they say "from" they really mean "through." To which my response has always been that it is a nice distinction but irrelevant since filioque in Latin means "from" and that is certainly the wording employed in the English translation of the Creed of the Council of Lyons.
Lex Orandi Lex Credendi The wording affirms a double procession irrespective of current "understanding." Said double procession is heretical. It's a non-negotiable point from an Orthodox perspective. We can not recite a heretical creed or be in communion with those reciting one.
But just as important, perhaps even more so, is the point I have repeatedly attempted to make to Catholics. What well versed theologians in their ivory towers understand is a whole different world from what the layman in the pews understands. He reads "from" and not being in possession of advanced degrees in theology he takes the wording at face value. Ergo "from" means "from."
Clearly large numbers of Catholics have not gotten the memo that the double procession has been developed away. For some evidence I would refer the reader to
a recent post over at the Traditional Catholic blog Rorate Caeli. The post expressly defends the filioque and a casual glance at the comments suggests that the double procession remains a point of carved in stone dogma for these Catholic traditionalists.
I believe the aforementioned blog post is the best refutation I have read in a long time of the many Catholics (and some Orthodox) who periodically spout off about how the filioque doesn't matter and Rome has "fixed" its interpretation to make it Orthodox. No they haven't. And clearly to the extent that there has been some movement on their part no one in the pews seems to have gotten the word.
The filioque is patently heretical and it must go.
HAEC LEO POSUI AMORE ET CAUTELA ORTHODOXAE FIDE-Inscription of Pope Leo III on a pair of silver tablest with the Creed (sans Filioque) placed in St Peter's Basilica in repudiation of the alteration to the Symbol of Faith.