|The Filoque Clause|
The Filioque is the portion of the Nicene Creed which reads in English as "and the Son." It is also known as double procession of the Holy Spirit, and was one of the points which caused the Great Schism of 1054 between the Eastern and Western Churches. Though there has been talk recently of agreement between the two groups over the issue of the filioque (such as a compromise reading "from the Father through the Son" instead of "from the Father and the Son"), conservatives from both sides deny that there can be any agreement, and each concludes that the other is in heresy.
Brief summary of Eastern and Western views
Roman Catholics maintain that the filioque is necessary because the Holy Spirit is the Spirit of Christ, who "the Father (sent) in (Christ's) name" (cf. John 14:26). Catholics also believe that to deny the procession of the Holy Spirit from the Son is to come uncomfortably close to denying the presence of the Spirit in Christ, which hints at Arianism. Since one of the comparatively minor issues which needed to be dealt with at the First Council of Nicea was the Pneumatomachian heresy that the Spirit had its origin in the Son, it was sufficient at the council to only state that the Spirit proceeded from the Father. But the Creed was not meant to deny the procession of the Spirit from the Son altogether.
On the other hand, Eastern Orthodox hold that the filioque has no place in the Nicene Creed. They cite John 15:26 ("the Spirit of truth who proceeds from the Father"), arguing that if the Spirit proceeds from the Son also, then Jesus would have stated such. They also claim that the filioque is redundant to its purpose of divinizing Christ and unifying the Trinity, since the rest of the Creed makes the divine nature of Christ and the unity of the Trinity quite clear. Moreover, Orthodox believe that the filioque makes the Holy Spirit a "lesser" member of the Trinity, subordinate to both the Father and the Son. This would violate the principle that each member of the Trinity is fully God, and suggest that the Spirit is not coeternal with the Father and the Son.