Most men think that the word “Godhead” is used in a peculiar degree in respect of nature: and just as the heaven, or the sun, or any other of the constituent parts of the universe are denoted by proper names which are significant of the subjects, so they say that in the case of the Supreme and Divine nature, the word “Godhead” is fitly adapted to that which it represents to us, as a kind of special name. We, on the other hand, following the suggestions of Scripture, have learned that that nature is unnameable and unspeakable, and we say that every term either invented by the custom of men, or handed down to us by the Scriptures, is indeed explanatory of our conceptions of the Divine Nature, but does not include the signification of that nature itself. And it may be shown without much difficulty that this is the case. For all other terms which are used of the creation may be found, even without analysis of their origin, to be applied to the subjects accidentally, because we are content to denote the things in any way by the word applied to them so as to avoid confusion in our knowledge of the things signified. But all the terms that are employed to lead us to the knowledge of God have comprehended in them each its own meaning, and you cannot find any word among the terms especially applied to God which is without a distinct sense. Hence it is clear that by any of the terms we use the Divine nature itself is not signified, but some one of its surroundings is made known. For we say, it may be, that the Deity is incorruptible, or powerful, or whatever else we are accustomed to say of Him. But in each of these terms we find a peculiar sense, fit to be understood or asserted of the Divine nature, yet not expressing that which that nature is in its essence. For the subject, whatever it may be, is incorruptible: but our conception of incorruptibility is this—that that which is, is not resolved into decay: so, when we say that He is incorruptible, we declare what His nature does not suffer, but we do not express what that is which does not suffer corruption. Thus, again, if we say that He is the Giver of life, though we show by that appellation what He gives, we do not by that word declare what that is which gives it. And by the same reasoning we find that all else which results from the significance involved in the names expressing the Divine attributes either forbids us to conceive what we ought not to conceive of the Divine nature, or teaches us that which we ought to conceive of it, but does not include an explanation of the nature itself. Since, then, as we perceive the varied operations of the power above us, we fashion our appellations from the several operations that are known to us, and as we recognize as one of these that operation of surveying and inspection, or, as one might call it, beholding, whereby He surveys all things and overlooks them all, discerning our thoughts, and even entering by His power of contemplation into those things which are not visible, we suppose that Godhead, or θεότης, is so called from θέα, or beholding, and that He who is our θεατής or beholder, by customary use and by the instruction of the Scriptures, is called θεός, or God. Now if any one admits that to behold and to discern are the same thing, and that the God Who superintends all things, both is and is called the superintender of the universe, let him consider this operation, and judge whether it belongs to one of the Persons whom we believe in the Holy Trinity, or whether the power extends throughout the Three Persons. For if our interpretation of the term Godhead, or θεότης, is a true one, and the things which are seen are said to be beheld, or θεατά, and that which beholds them is called θεός, or God, no one of the Persons in the Trinity could reasonably be excluded from such an appellation on the ground of the sense involved in the word. For Scripture attributes the act of seeing equally to Father, Son, and Holy Spirit. David says, “See, O God our defender”: and from this we learn that sight is a proper operation of the idea of God, so far as God is conceived, since he says, “See, O God.” But Jesus also sees the thoughts of those who condemn Him, and questions why by His own power He pardons the sins of men? For it says, “Jesus, seeing their thoughts.” And of the Holy Spirit also, Peter says to Ananias, “Why has Satan filled your heart, to lie to the Holy Ghost?” showing that the Holy Spirit was a true witness, aware of what Ananias had dared to do in secret, and by Whom the manifestation of the secret was made to Peter. For Ananias became a thief of his own goods, secretly, as he thought, from all men, and concealing his sin: but the Holy Spirit at the same moment was in Peter, and detected his intent, dragged down as it was to avarice, and gave to Peter from Himself the power of seeing the secret, while it is clear that He could not have done this had He not been able to behold hidden things.
But some one will say that the proof of our argument does not yet regard the question. For even if it were granted that the name of “Godhead” is a common name of the nature, it would not be established that we should not speak of “Gods”: but by these arguments, on the contrary, we are compelled to speak of “Gods”: for we find in the custom of mankind that not only those who are partakers in the same nature, but even any who may be of the same business, are not, when they are many, spoken of in the singular; as we speak of “many orators,” or “surveyors,” or “farmers,” or “shoemakers,” and so in all other cases. If, indeed, Godhead were an appellation of nature, it would be more proper, according to the argument laid down, to include the Three Persons in the singular number, and to speak of “One God,” by reason of the inseparability and indivisibility of the nature: but since it has been established by what has been said, that the term “Godhead” is significant of operation, and not of nature, the argument from what has been advanced seems to turn to the contrary conclusion, that we ought therefore all the more to call those “three Gods” who are contemplated in the same operation, as they say that one would speak of “three philosophers” or “orators,” or any other name derived from a business when those who take part in the same business are more than one.
I have taken some pains, in setting forth this view, to bring forward the reasoning on behalf of the adversaries, that our decision may be the more firmly fixed, being strengthened by the more elaborate contradictions. Let us now resume our argument.
Source: On "Not Three Gods" (To Ablabius) (New Advent)