Coherence of the Trinity

This post marks the beginning of a series exploring the meaning and coherence of the concept of Incarnation of Christ and the Divine Trinity, drawing insights from T. V. Morris, The Logic of God Incarnate (Cornell UP 1986) and Richard Swinburne, The Christian God (OUP 1994).


THE Coherence of the Trinity

Ng Kam Weng

It would be pretentious of me to suggest that such a complex philosophical problem as the coherence of the Trinity could be dealt with adequately in an appendix. My aim is rather modest. I shall only try to demonstrate that critics of the Trinity have failed to show how the doctrine of the Trinity is actually incoherent.

The Athanasian Creed gives us a useful starting point for our discussion: “We worship one God in Trinity and the Trinity in unity, without either confusing the persons or dividing the substance; for the person of the Father is one, the Son is another, and the Spirit is another; but the Godhead of the Father, Son and Holy Spirit is one, their glory equal, their majesty equally eternally. . . Thus, the Father is God, the Son is God, and the Holy Spirit is God; yet there are not three gods but one God. . . And in this Trinity there is no before or after, no greater or lesser, but all three persons are equally eternal with each other and fully equal.”

We may break down the above statement into the following propositions.

(1) The Father is God.

(2) The Son is God.

(3) The Holy Spirit is God.

(4) The Father is not the Son and the Son is not the Holy Spirit and the Holy Spirit is not the Father.

(5) There is one and only one God.

Critics have attacked the Trinity on two counts.
A. Statement (2) basically affirms the Incarnation of Christ or the teaching that Jesus Christ possesses both the divine and human nature, as a foundational truth for the formulation of the Trinity. Critics therefore charge that the proposition that Christ is both God and man is a contradictory statement. For example, John Hick alleges that the contradiction is of the same kind as that of affirming a ‘square circle’.

Now we have no problem in affirming that the ‘square circle’ is a contradiction since by definition a square excludes being a circle. Our definitions of a square and a circle are mathematically exact and we know precisely what we are talking about.

On the other hand, it is not obviously evident why God and man need to be mutually exclusive. Certainly we are not in a position to give an exact mathematical definition of God or man. We have not succeeded in defining exactly what man is, much less who God is. We have not been given cogent demonstrations why God could not act as a subject with the characteristics of divinity and humanity under the condition of earthly existence. We can argue that no man could assume Godhood, but there seems no logical limits to God taking up manhood or acting as a subject under conditions of humanity. At least critics like Hick have not demonstrated it.

Take also the case of Ahmad the (fictitious) chief minister of the state of Johor, who is also the father of Kamal now residing in Singapore. As minister Ahmad has authority over all citizens of the state of Johor. Being the father of Kamal he may exercise authority over Kamal. But his authority over Kamal is not by virtue of his position as chief minister. Neither is his authority over the state of Johor by virtue of his position as father of Kamal. The point is that we may recognize Christ as the subject of different things depending on whether we are thinking of him as God or as man. In other words, it is appropriate to predicate certain divine qualities (e.g. he is uncreated) as well as human qualities (e.g. he was thirsty) to Jesus without confusing them as identical things.

B. The second attack comes in the charge that statements (1) to (5) constitute what is logically termed an “inconsistent set”. The ‘proof’ comes in the form of showing how the set of propositions generate two contradictory statements. Thus,
statements (1), (2), (3) and (5) entail:

(6) The Father, the Son, and the Holy Spirit are one thing,

and (4) entails:

(7) The Father, the Son, and the Holy Spirit are separate things.

However, it is evident that (6) and (7) are inconsistent. Hence (1)-(5) is an inconsistent set of statements.

But the conclusion relies on a set of logical moves that fail to recognize that the Father, the Son and the Holy Spirit are separate things in a different sense from the sense that they are one thing. It is necessary to acknowledge how blurred the boundaries are with regard to what is a thing. Stephen Davis gives two useful illustrations:

(8) Joseph, Mary and Jesus are separate things and Joseph, Mary and Jesus are one thing.

Once we realize that each thing in the first clause refers to a person while the thing in the second clause refers to a family then there is no ground to conclude that a contradiction exists.

Davis continues:

(9) Lines AB, BC and CA are separate things and lines AB, BC and CA are one thing.

Again the contradiction is resolved if we recognize that the first thing refers to a line while the second thing refers to a triangle.

We may now reconsider (6) and (7). We may combine them to give

(10) The Father, the Son and the Holy Spirit are one thing and the Father, the Son and the Holy Spirit are separate things.

In the light of the earlier discussion on statements (8) and (9), it is obvious that different things are involved in the two occurrences in (10). There is no ground to judge the statement as self-contradictory.

Admittedly we may not be able to define exhaustively what these senses of thing are. The substance of thing here is a matter of historical investigation and religious experience. Even then, given human limitation in matters eternal, we can only expect tentative analogical conclusions. But at the level of logical form critics should at least concede that they have not proven conclusively that the formulation of the Trinity is a contradictory statement.

There are also other strategies to resolve the apparent contradiction of the doctrine of Trinity. Some philosophers, building on Peter Geach’s logical theory of “relative identity”, suggest that statements of identity are relative and statements like “ A = B ” are incomplete. The statement should be made more specific like saying that “ A = B “ with respect to x(God). The statement of the Trinity (F = S with respect to x) may be explained thus: The Father is the same God as the Son but is not the same person as the Son. The statement, ‘The Father is not the same person as the Son but is the same God as the Son’ is coherent. Hence the Trinity is coherent.

Perhaps this view enables us to appreciate better Karl Rahner’s description of the Trinity. “We may say that the Father, Son and Spirit are identical with one godhead and are ‘relatively’ distinct from one another. These three as distinct are constituted only by their relatedness to one another” (The Trinity, Burns & Oates 1970, p. 72).

To be fair, the concept of ‘relative identity’ is a difficult and controversial issue (which fundamental philosophical concept isn’t?). But perhaps the preliminary examples given are enough to indicate that there are logical resources in our reflection on the Trinity. In fact I have passed over the philosophical models of the Trinity by ancient thinkers like Augustine and modern philosophers like David Brown, T. V. Morris and Richard Swinburne since an appendix is not the place to provide a positive analogy. I am only attempting the negative defensive strategy of exposing the charges of incoherence for the Trinity to be less logically compelling than initially presumed. I can therefore conclude that there should be no logical barrier to prevent us from adopting an open mind and examining afresh the historical evidences to support the Trinity.

The above discussion is indebted to

Stephen Davis, Logic and the Nature of God. MacMillan, 1983.

Brian Davis, Thinking About God. Geoffrey Chapman, 1985.

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