I am, at present, trying to get my head around the infamous filioque clause in the Nicene Creed. It's amazing just how one word can represent so much perturbation in Catholic Christianity, but then again, the first four Oecumenical Councils showed that our faith does matter one iota!
So what's the problem?
Καὶ εἰς τὸ Πνεῦμα τὸ Ἅγιον, τὸ κύριον, τὸ ζῳοποιόν, τὸ ἐκ τοῦ Πατρὸς ἐκπορευόμενον
And [I believe] in the Holy Ghost, the Lord and Giver of Life, who proceedeth from the Father.
Here lies the epitome of the Schism between East and Western Orthodoxy. The Latin and the Greek do not match up, so Eastern and Western Orthodoxy do not match up. Does it matter?
Et in Spiritum Sanctum, Dominum, et vivificantem: qui ex Patre Filioque procedit
And [I believe] in the Holy Ghost, the Lord and Giver of Life, who proceedeth from the Father and the Son.
We are tempted to say that it doesn't matter all that much. Since it is only one word, surely we could agree to disagree, after all, shouldn't Christians be out there loving their neighbours, helping those in need and making life better for all those who suffer in so many ways rather than haggling and growling over one Latin word? Of course we should! God has shown that each human being has a value to their life that is not measurable within a purely empirical worldview. Theology can never be superior to the commandments of Almighty God. St Paul reminds us that knowledge puffs up, but love builds up.
However, we cannot separate the second commandment of Our Lord from the first commandment. St Luke records that Our Lord commanded "Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy strength, and with all thy mind."
Of course, being yet imperfect in ourselves, this commandment is an aspiration from which we cannot allow ourselves to rest. The Christian life is about repentance from sin towards this ideal. We are committed to love God with the mind and this means being sure that we are not worshipping a lesser deity who does not exist.
Our God is a Trinity and this must tax our minds beyond their limits. That's quite reasonable. the Trinity cannot be completely comprehended and it can only be formulated in very shadowy terms.
The word "person" has changed its meaning since the formulation of the Creeds and should not be understood in the same way as we might think of "that person over there".
We believe in God, Father, Son and Holy Spirit - One God, three persons. There are some very dull-witted philosophers out there who say that because One is not Three, this God cannot exist. Such folk haven't even begun to go beyond the superficialities of their own ignorance of Trinitarian doctrine and prefer the straw man that keeps them away from the Love that would give their lives a substance that they will never know.
We know that One of the Trinity is called "Father", another "Son" and the third "Holy Ghost". Logic tells us that one cannot be a father unless one has a child, and likewise, one cannot be called "son" without being able to refer to a father. So although the Father is God, and the Son is God, the Father cannot be a father were it not for the existence of the Son Whom Christian doctrine has already proved is consubstantial with the Father. I.e. whatever the Father is, so is the Son. A created "Son" could not be worshipped as God for, in being created, "He" ceases to be God.
The Arian controversy came about from confusing the Greek idea of "cause" as a succession of events rather than an explanatory relationship. The substance of God is beyond the created Universe and thus this causal relationship between Father and Son is also beyond the imagination of the creature. By calling the Son "Eternally begotten", we are saying categorically that the Father is causally responsible for the existence of the Son which is not representable in Time.
Can we say that? Yes we can, it's a consequence of what we understand the terms "father" and "son" to be and God Himself has used these very words when revealing Himself to us. Even if it is not actually true, it is a very forgivable misunderstanding. Of course, this doesn't tell us anything about what this "substance" is or how causes work beyond Time. There is plenty of mystery there for those who do not like to be certain about God.
Christianity proclaims its belief that God the Father is the Causeless Cause. If that is the case, then we must say that God is the Eternal cause of the Holy Ghost too. Yet we have Our Lord Jesus in John xx.22 breathing on His disciples and telling them to receive the Holy Spirit. The Holy Spirit is God and there is a clear causal relationship between Father and Spirit which is not the same as Father and Son. Scripture also shows a relationship between Son and Holy Ghost which cannot be causal without identifying Father and Son. Yet the Spirit is certainly sent forth by the Son just as willingly as the Son accepts Incarnation.
This does suggest that there is a very subtle distinction between "ἐκπορευόμενον" and "procedit" which are both translated "proceedeth". Do they really mean the same thing? I for one don't think that they do. The Greek is a causal statement, the Latin a missional statement. We cannot truly know the intimate details of the Godhead. Part of me thinks that it is somewhat voyeuristic to try, even if theosis involves being assumed into that perichoresis. Such knowledge can only come through the love of God and meek acceptance of His love and salvation.
St Basil and other Church Fathers would be happy to speak of the cause of the Holy Ghost as being from the Father through the Son. This means that there is only one causal procession, not a double causal procession. It is a procession from the Father-and-the-Son not a procession from the Father and a concomitant procession from the Son. Even then we do not have a real idea how causal procession works.
In all our reasoning, we have to be aware of our limitations. The only things we can say about God are pale shadows concepts of the truth, concepts which we are able to formulate or articulate between ourselves but lack the dimensions that only the beatific Vision can supply.
With the psalmist we cry:
" LORD, I am not high-minded : I have no proud looks.
2. I do not exercise myself in great matters : which are too high for me.
3. But I refrain my soul, and keep it low, like as a child that is weaned from his mother : yea, my soul is even as a weaned child.
4. O Israel, trust in the Lord : from this time forth for evermore." (Psalm cxxxi)
I am happy to say the Nicene Creed with and without the filioque.
If I say it without the filioque, then I assume that I am saying the Greek version. I affirm the Father as the Eternal Cause of the Holy Ghost and align myself with the Church of the East of which the ACC is a part. I also affirm that its presence in the Creed was not the definition of an Oecumenical Council.
If I say it with the filioque, then I affirm that the Son is the vehicle for the Holy Ghost from the Father for our Salvation. I also affirm that the nature of mutual relationships which differ between the persons of the Trinity to form the dynamic of Creation, Justification and Sanctification that will result in our theosis.
The filioque is truly an instance of different theologoumena and very valuable at that. Perhaps an Eighth Oecumenical Council will set things right. Or maybe the day will come when the veil is taken away.