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

134 Trinitarian Monotheism
controversies of the fourth century: ‘careless words are a slippery slope to
heresy’. Here more than anywhere else, it is necessary to take care to speak
prudently or with circumspection (cautela).31 ReXection on the two main
heresies calls for the elimination of certain words from our Trinitarian
language.
To avoid the error of Arius, one avoids speaking of diversity (diversitas) ordiVerence
(diVerentia) in God; that would destroy the unity of essence. But we can use the word
‘distinction’, on account of relative opposition. So if we come across a reference to
diversity or diVerence of persons in any authoritative text, we take it to mean
‘distinction’. Then, to safeguard the simplicity of the divine nature, it is necessary to
avoid the words separation (separatio) and division (divisio) which are a matter of a
whole divided into parts. To safeguard equality we avoid the word disparity (disparitas).
To safeguard the likeness [of the persons] one avoids the words alien (alienus)
and divergent (discrepans), following Saint Ambrose . . . and Saint Hilary....
On the other hand, to avoid the error of Sabellius, one avoids the words singularity
(singularitas) so as not to negate the communicability of the divine essence; this is why
Hilary says it is sacrilege to call the Father or the Son a single God. We must also avoid
the term unique (unicus) so as not to negate the plurality of persons: Hilary also says
that the idea of someone singular and unique is inapplicable to God. If we speak of ‘the
only Son’ that is because there are not several sons in God. But we do not call him ‘the
only God’ since the deity is common to several [persons]. We also avoid the term
conXated [confusus] lest we endanger the order of nature amongst the persons.
Ambrose thus writes: What is one is not ‘conXated’, and what is undiVerentiated cannot
be manifold. We must also avoid ‘solitary’ (solitarius) in order to respect the fellowship
of the three persons; for Hilary says, We should profess belief in neither a solitary nor a
diversiWed God.32
This discussion goes back over the rules for terminology which he gave in the
Commentary on the Sentences and in the Questions De potentia.33 This list
of proscribed words is not peculiar to him. It is an expression of the attention
paid to the quality of words, within the context of respect for language
which typiWes scholastic theology. Such a glossary is signiWcant to us because
of the way it is organized. Using a well-known method, St Thomas has pulled
his language together with the object of side-stepping Arianism and
Sabellianism.34 One can also observe the references to the Fathers of the
31 ST I, q. 31, a. 2; cf. I Sent. d. 24, q. 2, a. 1; De potentia, q. 9, a. 8: ‘it is necessary to speak of
God in such a way that one never creates an occasion for error’.
32 ST I, q. 31, a. 2.
33 I Sent. d. 24, q. 2, a. 1; De potentia, q.9,a.8.
34 This includes a study of antithetical parallelisms: there are thus four groups of words to
avoid in relation to Arianism, and also four for Sabellianism, as Thomas explains in his
Commentary on the Sentences (I Sent. d. 24, q. 2, a. 1) and in his Disputed Questions De
potentia (q. 9, a. 8).