You know, there is a difference between reason and rationalization, HD. The only Ecumenical Councils that were held are the first seven. The others were either not classified as ecumenical or were classified as ecumenical but were not for one reason or another.
Some of the doctrinal differences that exist between the east and the west have to do with the language used, with concepts, etc. which express either fully the same belief but in such a way tat it is not understood the same, or incompletely (such as in the case of the Purgatory and Filioque respectively).
In other cases a doctrine was developed by necessity, based on another doctrine that is itself not defined the same way between the east and the west (i.e. the "original sin"). Immaculate Conception is a perfect example of that.
The East does not deny that Theotokos was immaculate, but only that she was not conceived immaculately, which is taught by the Latin side as a necessary dogma based on Augustinian concept of the "original sin," which the east never taught.
Individual teachings of various Fathers that do not agree with Councils are not heretical. They represent theological opinions and hypotheses, but not doctrine. Thus, Catholics were allowed to believe in the Limbo, but were not required to.
The concept of limbus patrum to which both Churches held, as a state where the souls of the OT Righteous were before Resurrection, served as a precedence for a hypothesis of limbus infantum.
Our differences are not heresies: they represent disagreements within the Church, and such disagreements were addressed by various councils, both general (Ecumenical) or local. The important point is to remember that only the Ecumenical Synods are binding, but even there one finds that somehow discipline and habits sometimes do not follow the declarations of the Church completely.
The best example is prohibition of kneeling on Sundays (by the First Ecumenical Council), yet Roman Catholics, Antionchan Orthodox (in America), Greek Orthodox (in America), etc. habitually kneel on Sundays. Kneeing is especially proscribed during 40 days after Resurrection. If one is to follow the First Ecumenical Council, the proper way to attend Divine Liturgy is only by standing (exception being the Pentecost when there is kneeling).
That's why "old country" Orthodox parishes never have pews (the Church is supposed to be a home, not a theater!), and there are chairs along the walls for the sick and weak (pregnant, elderly, etc.), but at no time is one supposed to be comfortable in church. One does not go to church to relax, but to stand in awe.
"That's why "old country" Orthodox parishes never have pews (the Church is supposed to be a home, not a theater!), and there are chairs along the walls for the sick and weak (pregnant, elderly, etc.)...."
Those are always my excuses (well, not pregnancy) for using them when I'm in Greece! :)
Actually, no, we don't. Sorry.