"Arians operated with the principle that what they could not humanly conceive could not be. That is to say, they equated the limits of their understanding with the limits of reality, and thereby laid down conditions for their understanding of God and their interpretation of divine revelation. It became increasingly evident to the Nicene theologians, however, that all such ways of thought shattered themselves upon the transcendent Lordship of the Holy Spirit which means that God can be known only through and out of himself" (The Trinitarian Faith, 207).
It seems to me that this is part of our struggle today: God as I understand him/her/it from within myself, my comprehension, my experience; contrasted with God as he reveals himself, known only through and out of himself: "No one has seen God at any time. The only begotten Son, who is in the bosom of the Father, He has declared him" (John 1.18).
The question is how do we move away from the one and toward the other?
I love the point Paul makes in Ephesians 3 of the love of Christ, which love is beyond knowledge! And the prayer in verses 20-21 that expresses the expansive reality of God as beyond my ability to ask or think [noeo -- to think, comprehend, conceive!]. Or the promise, in Philippians, of the peace of God which is superlatively beyond our comprehension.
Maybe the way to begin this trek of moving from an Arian framework toward a more orthodox one is to recognize that our natural, knee-jerk reaction is to make god in our image, limited to our ability and tamed by our comfort-zone. Then, to turn toward the One who has condescended to our infantile abilities, and started making himself known to us in Jesus Christ... But there is so much more, and only eternity will open up to us greater and greater comprehension of this God, "that in the ages to come He might show the exceeding riches of His grace in His kindness toward us in Christ Jesus" (Eph. 2.7).