Basil Contra Eunomius 1.10

Such is the situation. There is no one name which encompasses the entire nature of God and suffices to express it adequately. Rather there are many diverse names, and each one contributes, in accordance with its own meaning, to a notion that is altogether dim and trifling as regards the whole but that is at least sufficient for us. Now some of the names applied to God are indicative of what is present to God; others, on the contrary, of what is not present. From these two something like an impression of God is made in us, namely, from the denial of what is incongruous with him and from the affirmation to what belongs to him.

For example, whenever we call him ‘incorruptible’, we are implicitly saying to ourselves or to those who hear us: “Do not think that God is subject to corruption.” Whenever we call him ‘invisible’: “Do not suppose that he can be comprehended by the perception of what comes through the eyes.” Whenever we call him ‘immortal’: “Do not think that death happens to God” It is the same whenever we call him ‘unbegotten’: “Do not believe that the being of God depends on any cause or principle.” On the whole, we learn form each of those names not to fall into inappropriate notions in our suppositions about God. So, then, in order that we may come to know the particular distinguishing mark about God, in our statements about God we forbid each to lower thoughts to the level of what is not appropriate. We do this so that human beings will never consider God to be one of the things that are corruptible, or one of those things that are visible, or one of those things that are begotten. Forbidding all these names results in something like a denial of what is foreign to him, since our minds articulate distinctly and cast aside the suppositions concerning what is not present to him.

Again, we say that God is ‘good,’ ‘just,’ ‘Creator,’ ‘Judge,’ and all such things. So, then, as in the case of the terms we just spoke about which signified a denial and rejection of what is foreign to God, so here they indicate the affirmation and existence of what has affinity with God and is appropriately considered in connection with him. Accordingly, we learn from each of the two forms of designation either that what is present is present or that what is not present is not present to God. But it makes no difference to us if someone wants designate this a ‘negation’ or a ‘rejection’ or a ‘denial’ or some such thing. I think that what I have said has sufficiently demonstrated that ‘unbegotten’ is not indicative of what belongs to God. Now the substance is not one of the things not present, but is rather the very being of God; indeed, it is the pinnacle of insanity to count it among that which does not have being. For if the substance is among that which does not have being, then it could hardly be the case that any of the other things we have mentioned has being. So, then, it has been demonstrated that ‘unbegotten’ is classed with what is not present. Therefore, whoever holds that this term is indicative of the substance itself is a liar.