Basil: Contra Eumomius 1.15

So, then, when we reflect upon the matter, we find that our notion of unbegottenness does not fail under the examination of ‘what it is’ but rather—and here I am forced to speak this way—under the examination of ‘what it is like.’ When our mind scrutinises whether God who is over all (Rom 9.5) has some cause superior to himself, then, unable to conceptualise any, it designates the fact that this life is without beginning as ‘unbegotten.’ When we talk about human beings and say that this person has come from that person, we are not relating  the ‘what it is’ of each but the ‘from where he has come.’ Similarly, when we talk about God, the term ‘unbegotten’ does not signify his ‘what’ but that he is ‘from no source.’

My point can be clarified as follows. When Luke the evangelist recounted the genealogy of our God and Saviour Jesus Christ according to the flesh, he worked his way backwards from the last to the first. He began with Joseph, saying that he was the son of Heli, who was the son of Matthan. He traced the lineage similarly all the way back to Adam. When he reached the end, he said that Seth came from Adam but that Adam came from God, and stopped there. In narrating the begetting of each person, he did not indicate the substances of those enumerated but recounted the proximate origin from which each one came. So just as Luke said that Adam came from God, let us ask ourselves: “Did God come from anyone?” Isn’t it obvious in each one of our minds that God came from no one? Clearly, that which is ‘from no one’ is ‘without origin,’ and that which is ‘without origin’ is ‘unbegotten.’ Therefore, just as being ‘from someone’ so too when we are talking about the God of the universe it is not possible to say that ‘unbegotten’ (which is equivalent to saying ‘from no one’) is the substance. Whoever says that being ‘without origin’ is the substance equates himself with someone who, when asked, “What is the substance of Adam? What is his nature?” replies that he is not formed from the copulation of a man and a women, but rather by the divine hand. The recipient of such a reply may object: “I am not seeking the manner of his subsistence but rather the material substrate of the man himself. Your response has not answered my question.” So, then, this is how it is for those of us who have learned from the term ‘unbegotten’ what God is like rather than his very nature.