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

26 Speculative Trinitarian Theology
a clear-cut divide between the domain of faith and that of natural reason: this
straightforward distinction is one of Thomas’ most outstanding features,
particularly by comparison with Bonaventure. This means that the reasons
which theology uses to exhibit the Trinitarian mystery will never be demonstrative
proofs. Rather they will be one of two things: either ‘approximations’
or ‘probable arguments’24 that is, arguments which show that what the faith
proposes is not impossible, or arguments drawn only from faith.25
In his approach to the Trinity, Thomas’ epistemic method is thus characterized
by two constant features: First, the strict exclusion of the idea that
Trinitarian faith can be established by necessary reasons,26 and second, taking
it to be impossible either to conceive the Trinity by deducing it from the divine
unity or to think of the plurality of persons as deriving from the essential
attributes.27 This second thesis, which is too often neglected, is one of the
fundamental features of Thomas’ Trinitarian theology. Thomas was a more
rigorous thinker than most of his contemporaries, and he wields that rigour
in his barring any confusion between our knowledge of the divine essence and
our knowledge of personal plurality in God; he strictly refuses to consider
God’s personal plurality as the fruit of an essential fecundity of the divine
being. Hence it is necessary to pin down what we mean by the role of human
reason in Trinitarian theology.
(c) Understanding the Faith
We are now in a position to understand the problem which presents itself to
Trinitarian theology: if, on the one hand, natural human intelligence has
no access to the existence of a Trinity of persons in God (since only faith
gives knowledge of it), and if, on the other hand, the speculative reasons
advanced by Christian theology are not demonstrations, what could be the
value of a speculative discussion which makes use of ‘reason’, and what is the
discussion for?
The treatise on the Trinity develops many themes which are applied to God
by the use of analogy (person, relation, order, origin, procession, etc.); the
properties of the persons are also set out by means of analogies derived from
24 I Sent. d.3,q.1,a.4,ad3(adaptationes quaedam); SCG I, chs. 8–9.
25 ST II–II, q. 1, a. 5, ad 2.
26 See R. L. Richard, The Problem of an Apologetic Perspective in the Trinitarian Theology of
St. Thomas Aquinas, Rome, 1963.
27 See our study: ‘Essentialisme ou personnalisme dans le traité de Dieu chez St Thomas
d’Aquin?’ RT 98 (1998), 5–38; cf. H. C. Schmidbaur, Personarum Trinitas: Die trinitarische
Gotteslehre des heiligen Thomas von Aquin, St Ottilien, 1995.