Version: v1, Published online: 1998
Retrieved November 18, 2018, from https://www.rep.routledge.com/articles/thematic/trinity/v-1
The doctrine of the Holy Trinity is a central and essential element of Christian theology. The part of the doctrine that is of special concern in the present entry may be stated in these words: the Father, the Son and the Holy Spirit are each God; they are distinct from one another; and yet (in the words of the Athanasian Creed), ‘they are not three Gods, but there is one God’. This is not to be explained by saying that ‘the Father’, ‘the Son’ and ‘the Holy Spirit’ are three names that are applied to the one God in various circumstances; nor is it to be explained by saying that the Father, the Son, and the Holy Spirit are parts or aspects of God (like the leaves of a shamrock or the faces of a cube). In the words of St Augustine:
Thus there are the Father, the Son, and the Holy Spirit, and each is God and at the same time all are one God; and each of them is a full substance, and at the same time all are one substance. The Father is neither the Son nor the Holy Spirit; the Son is neither the Father nor the Holy Spirit; the Holy Spirit is neither the Father nor the Son. But the Father is the Father uniquely; the Son is the Son uniquely; and the Holy Spirit is the Holy Spirit uniquely.
(De doctrina christiana I, 5, 5)
The doctrine of the Trinity seems on the face of it to be logically incoherent. It seems to imply that identity is not transitive – for the Father is identical with God, the Son is identical with God, and the Father is not identical with the Son. There have been two recent attempts by philosophers to defend the logical coherency of the doctrine. Richard Swinburne has suggested that the Father, the Son and the Holy Spirit be thought of as numerically distinct Gods, and he has argued that, properly understood, this suggestion is consistent with historical orthodoxy. Peter Geach and various others have suggested that a coherent statement of the doctrine is possible on the assumption that identity is ‘always relative to a sortal term’. Swinburne’s formulation of the doctrine of the Trinity is certainly free from logical incoherency, but it is debatable whether it is consistent with historical orthodoxy. As to ‘relative identity’ formulations of the doctrine, not all philosophers would agree that the idea that identity is always relative to a sortal term is even intelligible.
van Inwagen, Peter and Dan Howard-Snyder. Trinity, 1998, doi:10.4324/9780415249126-K105-1. Routledge Encyclopedia of Philosophy, Taylor and Francis, https://www.rep.routledge.com/articles/thematic/trinity/v-1.
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