The Unity of God

G Deegan

The unity of God is a basic truth of Biblical revelation. But outside the monotheism of Israel and Christianity this unity was far from being clearly perceived or fully acknowledged by philosophers. In a sense it is surprising that God's unity is treated as the last of the entitative attributes. One of the reasons for this particular position is that the unity of God was only acknowledged with great difficulty, if at all, by philosophers. Even if it can be demonstrated by reason, the fact that God alone is to be adored is a conclusion that philosophers did not in fact reach.

The search for unity had marked Greek philosophy from the beginning. The earlier cosmologists attempted to find one 'arche' (principle and common material) from which all beings come forth. Heraclitus believed that he had discovered many contrary things are really one. For Parmenides there exists only one corporeal reality. The world of change and multiplicity is not real. Plato upheld the unity of the world. Moreover, he established a theory according to which all of reality and even the Ideas originated from two first principles the One and the Indefinite Dyad. In his treatise on the First Unmoved Mover Aristotle quotes the words of Homer that the government of the universe must be in the hands of one. Nevertheless, in some texts Aristotle asserts that there is a plurality of Unmoved Movers.

In Neoplatonism the ineffable supreme principle is call the One. Unity precedes multiplicity and all multiplicity must be reduced to unity. In Neoplatonism the One is before and above being. What is correct in this view is that in order to be something has to have unity and that unity is also the principle of knowledge. Dionysius considers divine unity a primary and absolute value and calls God super-one and super-unity.

Over against this Neoplatonic tradition, St. Thomas affirms the priority of being over unity. Being is first to enter the intellect To being all other concepts are reduced. Unity does not add something positive to being, but merely the negation of division. Aquinas demonstrates God's unity by means of three arguments.

1) That which makes a man or a thing 'this particular man' or 'thing' is communicable only to one. "If Socrates were a man by what makes him to be this particular man, as there cannot be many Socrates, so there could not in that way be many men. Now this applies to God alone: for God himself is his own nature as was shown above (13, 3). Therefore in the very same way God is God and this God. It is impossible therefore that there should be many Gods.

2) God comprehends in himself the whole perfection of being. If many gods existed, they would differ and one of them would not have something proper to the other. In that case God would not have the whole perfection of being. This argument is already used by Parmenides, who excluded multiplicity in being: being is being and cannot be different from another being because a real difference would also be being. This second argument recalls the all-surpassing plenitude and perfection of God.

3) The third argument is based on the comprehension of the unity of the world. In the universe things are ordered to one another. They would not have this order unless one being is 'per se' the cause of it. The unity of a design in which many components are involved cannot consistently be explained by many different agents, but must have a cause 'per se' which is one. Some have objected that the existence of more worlds is possible, each of which would have its own god, but entirely unrelated worlds are unthinkable. Where there is a relation, a Supreme Mind must bring about this order.

Unity means being undivided. In order to be one in the highest degree a thing must be being in the highest degree as well as undivided. Both conditions obtain in the case of God, for he is subsistent be itself and supremely undivided. God's unity is given with his subsistent be, which surpasses infinitely whatever being is in our world.

G Deegan

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G Deegan, M.A. Ph. D. is a former lecturer of the CTS.

This article posted May 2005. It was published in Universitas Number 11 (May 2005)
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