Aquinas and Zizioulas on the Doctrine of the Trinity
(‘Treatise on the Most Holy Trinity’ & ‘The Significance of the Cappadocian Contribution’ )
For Aquinas, the doctrine is very much relation based. There are two processions in his view ( ‘the Catholic Church understands procession as existing in God’ ) ; the procession of the Word, and the procession of Love as Spirit. ‘No other procession is possible in God but the procession of the Word, and of Love.’ The procession of the Logos is generation as He proceeds, due to intelligible action and intellectual likeness. Aquinas argues that when something ‘proceeds of the same nature’, they agree in the same order, and they therefore have real relations with each other. Aquinas claims that relation is the same as essence. ‘In God relation and essence do not differ.’ The central idea of relation seems to be distinction in God - as in each of the processions ( the Word and Love) there is distinction, and therefore two opposite relations occur. The term ‘individual substance’ simply means person (singular and rational), as opposed to the greek definition of substance which is ουσία. Aquinas writes that person signifies a relational ‘subsistent individual of a rational nature.’
The Cappadocian doctrine of the Trinity is centred around personhood. As for God’s substance, Zizioulas writes that nothing can be said about it except that ‘it is one, undivided and absolutely simple and uncompounded.’ A person is defined through properties ( rather than nature/substance ). This is where the greatest difference between Aquinas’ view and Zizioulas’ theology unfolds - and that is with regard to substance. For Zizioulas there is a clear distinction between person and the substance/nature of God, and for Aquinas they ‘do not differ.’ Substance refers to created matter in the Cappadocian theology, and so the Triune God cannot be connected to such a phrase. The Three Persons ‘are not faced with a given substance, but exist freely.’ St Gregory of Nazianzus tells us that the cause of divine existence is the Father, which contradicts Aquinas’ view of necessary generation. St Gregory and St Cyril of Alexandria argue that the idea of generation is unnecessary, as there is The ‘Willing One’ - God the Father, Who is the cause of divine being. This is where we see the contrasting views of Eastern Orthodox, and western Theologies ( Creed of Nicaea ). A frequently asked question, is why or how is God Love? (1 John 4:8) Zizioulas’ piece answers this very beautifully - explaining that Love is a relationship, as it is breaking of one’s will, a free submission to the other, and therefore freedom. God is Love as He is Father, Son and Holy Spirit - a perfectly free, relational unity. Aquinas on the other hand, does not seem particularly aware of this connection, and concentrates on love being a procession in God, as opposed to God Himself ( by nature ) Zizioulas concludes his piece by highlighting how we can fulfil our personhood by ‘living according to the image of God’, in a full communion with Him, which leads to theosis ( complete unity with God ). This takes place through asceticism and a growing and loving relationship with Christ.