The Arian controversy was not settled at the great convention in the balmy resort city of Nicæa (AD 325). Even with more than 300 conventioneers present, and despite a couple of months of all day meetings followed by casual conversations in the bar, sipping colorful drinks topped with paper umbrellas and orange slices, some of the boys still weren't satisfied with the (now orthodox) assertion that Jesus is homoousios to Patri: "of one substance with the Father." You remember: God of God, Light of Light, Of one substance with the Father . . .
The problem was the modalists. That's right, the ones that said God is one person who wears three different hats depending on the mood he's in. The modalists decided to "spin" homoousios and make it say, not same substance, but same person: in other words, the Father and Son are one person, not just one substance. That kind of spin wasn't hard to do in those days because the Greek words for person and substance were often used interchangeably. (That would get straightened out later).
Some of the other boys who had attended the convention didn't think much of what the modalists were up to. They didn't like the three-hat scenario. So they decided the best way to flank the modalists was to change same substance to "similar" or "like" substance." That way they could get around the modalist spin on homoousios (same substance) and say, "See! They're not one person 'cause their not the 'same'; they're similar." Here's how it works in the Greek language: they wanted to change homoousios (same or one substance) to homoiousios (similar or like substance). Only one little letter different. Did you catch it? Just one little-bitty "i" right there in the middle. But man, does it make a difference.
Constantine, who wanted to keep everybody happy to avoid more riots in the streets, decided to go along. Even though the emperor himself had contributed the word homoousios (same substance) to the convention (that's a popular rumor but I doubt it's true), he agreed to change the word by that one little letter "i" to homoiousios as the "official" assertion of the relationship between the Father and Son. This was a kind of "semi-Arian" compromise; maybe just enough to satisfy the Arians who said Jesus wasn't divine like the Father and, at the same time, satisfy those who were afraid of modalism. The compromise seemed so reasonable that pretty much everybody decided to become semi-Arians and adopt the new word, homoiousios.
Everybody but one that is. Enter the stalwart defender of Nicene orthodoxy: the Black Dwarf—six guns blazin', white hat gleaming in the desert sun—none other than the great Athanasius, the new senior pastor from Alexandria. Athanasius stood alone against the world (contra mundi). (Get ready. Here comes the serious stuff:J) Athanasius stubbornly refused to go along with the popular compromise to the Nicene language. He understood that the implementation of homoiousios ("like substance") was tantamount to asserting that Jesus is not God. As Athanasius realized, the difference between homoousios and homoiousios is the difference between the divine and the creaturely. The former says that the Son is God; the latter that the Son is merely like God (Olson, 1999:165). For Athanasius, the good news of human salvation was at stake with the reintroduction of the pre-Nicene subordinationism implied in the word homoiousios (i.e., Jesus as only similar to God is "less divine" than the Father; hence, ontologically subordinate). According to Athanasius, the Son must be God, not merely a creature, for only God can unite creatures to God. Salvation is not possible through a hierarchal chain from the Father through the intermediate Son, for an intermediary divides as much as it unites (Olson, 1999:164, 165). If the Son is not God in the same sense that the Father is God, then we are not saved, for only God can undo sin and bring us to share in the divine nature (Olson, 1999:169; cf. Gonzales, 1987:298; Torrance, 1995:149).
Athanasius rejected the "Arian disjunction" between the being of the Son and the being of the Father and confirmed the Nicene homoousion as showing that the Son belongs on the divine side of the Creator-creation relationship (Torrance, 1995:86). (NOTE: To get at what Torrance is saying, draw a vertical line with divinity on the left side and creation on the right. Where do we put the Son? Arius says on the right because, according to him, the Son is a created, not eternal, intermediary between the world-transcending Father and us. Athanasius, on the other hand, says put the Son on the left, because he is the eternally begotten (not made) Son who is "of one substance with the Father" (homoousios to Patri)). According to Athanasius, the Nicene homoousion asserts that God has became man in such a way as to give us access through the Son and Spirit to the Father himself (Torrance, 1995:130; cf Eph 2:18). The phrase homoousios to Patri ("of one substance with the Father") expresses the fact that what God is toward us, in the midst of us, and for us through the eternal Word made flesh, God really is in himself. In other words, God is, in the internal relations of his eternal being, the same Father, Son, and Spirit that he is in his redemptive activity for us in the incarnate Son and the gift of the Spirit (Torrance, 1995:130).
Moreover, Athanasius recognized the importance of relationality in the doctrine of the Trinity. For Athanasius, the fatherhood of God belongs eternally to God and defines the being of God (O'Collins, 1999:128). While God has not always been Creator, God is eternally Father (Torrance, 1995: 87). Athanasius articulated the fundamental trinitarian principle that the Father-Son relationship defines, at least in part, the word God (O'Collins, 1999:128). Following the Nicene creedal affirmation that the Son is "begotten, not made," Athanasius distinguished the divine operations of generation and creation to assert that God is inherently relational and generative. Against Arius, he argued that the denial of the eternal existence of the Son is a denial of the eternal fatherhood of God. Moreover, Athanasius asserted that one can know or say nothing of any one person of the Godhead in isolation from the other two (O'Collins, 1999:129, 130). The Athanasian (and Cappadocian) emphasis on relationality in the Godhead is markedly different from the Augustinian-Thomist-Western emphasis on the impersonal "substance" of the Godhead.
As the fourth century progressed, Athanasius was exiled numerous times by Constantine and the emperors that followed. Yet the Black Dwarf refused to compromise the Good News that Jesus is the revelation of God. Jesus is not merely like God; Jesus is God, the eternally begotten Son who has reconciled all things to the Father (2Cor 5:19). As theologian Roger Olson (1999:161) notes, without the steadfast determination of Athanasius to defend the full divinity of the Son, the Christian doctrine of God would closely resemble that of today's Jehovah's witnesses.
Gonzalez, J.L. 1987. A History of Christian Thought (vol 1). Nashville, TN: Abingdon Press. 400pp.
O'Collins, G. 1999. The Tripersonal God: Understanding and Interpreting the Trinity. New York, NY: Paulist Press. 234pp.
Olson, R.E. 1999. The Story of Christian Theology. Downers Grove, IL: IVP. 652pp.
Torrance, T.F. 1995. The Trinitarian Faith: The Evangelical Theology of the Ancient Catholic Church. London: T & T Clark. 345pp.