The Arian doctrine is based on a special interpretation of Origen's subordinatianism of the three hypostases of the Trinity consisting of God, Logos-Son and Holy Spirit:
"If the Father and the Son are two persons, then one would violate the precept of monotheism if one supposed that the Father and the Son were of the same essence, for then one would have two gods; but, on the other hand, they cannot be one person, for that would be modalism, which has likewise already been condemned."
Arius, based on his religious philosophical education (which was primarily based on Plato), held the following positions regarding the Trinity and Christology:
- that God begat the Logos Son by his own will out of nothing, that the Logos Son was thus not begotten out of the being of God
- that the Logos and the Father are accordingly not of the same essence (equality of essence)
- that only God is therefore true God, the Logos Son, on the other hand, is not true God
- that the Son is a creature of the Father, albeit a unique one.
- that God only became Father when he begat the Logos Son.
- that there was a time when the Son did not yet exist; he had a beginning (denial of the beginningless equality of Father and Son, see pre-existence of Christ)
- that the Logos Son is therefore subordinate to God (see subordinatianism)
For Arius, God "the Father" is thus unbegotten and unbegotten, beginningless and eternal, unchangeable as well as unchangeable and absolutely transcendent. The Logos Son is created as an independent hypostasis like everything outside of God, yet directly from God, yet not identical with the Logos indwelling God. Accordingly, Christ as the bearer of the created Logos was also created before an unthinkable time, but there was a - logical - time in which Christ had not yet been created. With Arius the Logos becomes the not divine, but special mediator of creation, with which God created all further creatures. Accordingly, Jesus is regarded by Arius as created and thus as not divine, not consubstantial with God. Moreover, only a man could die suffering on the cross, not a God; the human nature was therefore dominant in Christ.
The following disputes about Arius' statements concentrated mainly on the theses that Logos Son/God's Son respectively Father Son was "created" and had a beginning. Analogously, the Logos Son was not a true God for Arius. But for the critics of Arius' theses the redemption through the New Testament Christ was inevitably connected with the fact that the Logos Son respectively Father Son was also true God.
The Christological and Trinitarian questions shaped the time until the 6th century. Arius found followers especially in educated Hellenistic circles, since his understanding of the Trinity had been co-influenced by Middle Platonism and Neoplatonism and had been communicated especially by Clement of Alexandria and Origen in the educated, Greek-speaking Christianity of the Eastern Mediterranean. The postulate of the unity of God against gnosis led them to hold to the subordination of the Son to the Father.
Just like the "Nicene Trinitarians" the "Arians" referred to the Bible; as with them, in some directions of supposedly "Arian" currents the inspiration by the Spirit of God played an important role, in others the appeal to Aristotelian philosophy. In the biblical justification of their doctrine the Arians often quoted other passages than the Nicene (= followers of the Council of Nicaea); for the New Testament contains no clear statements about the nature of Jesus. In particular, they referred to the Bible commentary of Origen, who held to the unity of essence of the Father with the Son, who came to his divine nature before all time through inner divine procreation: "Now it is possible that some do not appreciate what we said by putting the Father as the one true God and admitting that other beings besides the true God could become gods by partaking of God" and to Tertullian, who had taught that Jesus was subordinate to the Father (subordinatianism).
