The Trinitarian Theology of Saint Thomas Aquinas - El Camino ...

90 Relations
with the conception of person as a subsistent relation for which it is the
preparation, this stage of the argument supplies the key to St Thomas’
Trinitarian theology.
At an historical level, Thomas formulates this question in reference to
Gilbert de la Porrée (þ1154). The Chancellor of Chartres, professor in Paris
and then bishop of Poitiers, Gilbert had been an outstanding Wgure within
twelfth-century theology. When commenting on Boethius, he had taken care
to show that the Trinity is compatible with the unity of God. So as to hold
on to the unity of the divine essence, which is absolutely identical in each
divine person, he had explained that the divine persons are not contrasted on
the level of their essence, which is identical, but distinguish themselves from
one another by a relation which Gilbert deWnes as ‘extrinsic’ or as ‘extraneously
labelled’ (extrinsecus aYxa).54 Gilbert uses the word ‘external’ to
indicate that the relation does not belong to the order of essence, that is,
the divine unity, but to the order of the distinction of the persons, which does
not touch their essential unity. He also takes over from Boethius the distinction
between abstract forms (that by which a thing is such) and the concrete
subject (the concretely existing subsistent individual). He makes an analogous
distinction in God: there will be a diVerence between the divine person and
his relative property, for instance, between the Father and his paternity. This
idea elicited heated reactions, especially from Bernard of Clairvaux, who
counter-attacked in the name of God’s simplicity. The theory would be
rejected at the synod of Reims (1148), whose doctrinal decision was accepted
by Gilbert. Whatever its accuracy with respect to Gilbert’s actual thinking, the
criticism which it addressed to him constituted the scholastic form of ‘Porretanism’,
as the kind of Trinitarian theology which Peter Lombard’s Sentences
characterized as ‘heretical’.55 It is found throughout the whole of theological
Trinitarian writing, from the middle of the twelfth century right down to the
fourteenth century and beyond.
At a theoretical level, St Thomas draws out the thinking of his teacher
Albert the Great.56 Albert had stressed that relation simultaneously secures
the plurality of divine persons and the simplicity and immutability of God.
54 Gilbert of Poitiers, Expositio in Boecii de Trinitate I. 5, nn. 42–43 (ed. N. M. Häring, The
Commentaries on Boethius by Gilbert of Poitiers, Toronto, 1966, p. 148); cf. II.1, n. 37 (pp. 170–
171). For an overview and bibliographic references, see our article, ‘Trinité et Unité de Dieu dans
la scolastique, XII e –XIV e siècles’, in Le christianisme est-il un monothéisme?, ed. P. Gisel and
G. Emery, Geneva, 2001, pp. 201–204.
55 Peter Lombard, Sentences, Book I, dist. 33, ch. 1 (vol. I/2, Grottaferrata, 1971, pp. 240–
243).
56 For more details and reference to Albert’s texts, see our article, La relation dans la théologie
de saint Albert le Grand, pp. 457–461.