The Council removed the condemnations, which were added to the Council of Nicaea, because they didn’t fit the new terminology any more; and it did something else that was important and which was lacking in Nicaea, namely they said about the Holy Ghost: “And in the Holy Spirit, the Lord and Giver of life, Who preceedeth from the Father, Who with the Father and the Son together is worshiped and glorified.” Of course the latter phrases are more mystical and liturgical; but these abstract formulas mean more than they would mean for us, or for a logical positivist. They mean mystical power, at the same time, and therefore they can be used liturgically.
This decision ends the Trinitarian struggle. Arius and Sabellius and many of their mediating followers were excluded. The homoousios stands now against Arius in all subsequent Church history. But it was interpreted as homoiousios (as similar with God) against Sabellius.
Now in all this the negative side of the decision is clear, but its positive side, the implications for a development of the Trinitarian doctrine, are extremely difficult. I will show you the four main difficulties.
1) The Father is, on the one hand, the ground of Divinity. He is, on the other hand, a special persona, a special hypostasis. Now if you take these two points of view together, then it is possible to speak of a quaternity instead of a trinity, namely to speak of the Divine substance as the one Divine Ground, and the three persons, Father, Son and Spirit, as the manifestations of this Ground. Then we have a quaternity instead of a trinity. And there was always an inclination in this direction, and Thomas Aquinas still had to fight against it. Usually theology said: He who is the Father is at the same time the source of all Divinity, and that means, of the other manifestations also.
2) The distinctions in eternal Trinity are empty. The Trinity was created in order to understand the historical Jesus. As long as this was kept alive, there was a difference between God and him very evident. But now we are in the realm of a transcendent Trinity. How can differences be made there? They are made by words: like non- generated, generated, and proceeding. But what do these words really mean? They are words without content, because there is no perception of any kind which can confirm their meaning. And to anticipate something of Augustine: Augustine said these differences are not expressed because something is said with them, but in order not to remain silent about the differences. This means: If the motives of Trinity are left and lost, then the formulas become empty.
3) The Holy Spirit remains even now an abstraction. He is brought in concretely only if He is defined as the Spirit of Christ, namely of Jesus as the Christ, but if He is put into the transcendent Trinity, then He is more an abstraction than a person.
Therefore He never had very great importance for Christian piety. At the same time in which He was deified, in the same sense in which Christ was deified, He was replaced in actual piety by the Holy Virgin, who as the one who gives birth to God, received Divinity very much herself, at least for popular piety.