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

Procession of the Holy Spirit 281
the Father and the Son, who are called ‘principle’ (principium), ‘author’ (auctor),
and ‘source’ (fons) of the Spirit.60 Amongst these expressions, the terminology
of procession and principle is best tailored to designating the origin of the
Holy Spirit.
Despite his evident limitations, Thomas was not as naive or ignorant about
the meaning of ekporeusis as people often imagine. Even though the distinction
between the words processio and ekporeusis escaped him, he nonetheless
grasped the heart of the matter when he observed that the Latin preposition a
or ab translates the Greek ek or ex, that is to say, ‘from’ or ‘out of’ (‘the Spirit
who proceeds from the Father’ does not follow the text of John 15.27, which
uses a diVerent preposition, but the text of the Constantinopolitan Creed; the
word ek-poreusis likewise contains this root in its preWx). Thomas makes this
observation in his Commentary on the Sentences:
It is said that ‘the Holy Spirit principally proceeds from the Father’, because the
auctoritas [authorship] of the spiration resides in the Father, and since it is from
the Father that the Son receives the power to breathe the Spirit . . . One accurately says
that ‘the Spirit proceeds from the Father (a Patre)’, mainly because, for the Greeks, the
preposition ‘a’ designates the relation to the primary point of origin (prima origo);
this is why one does not say that the lake proceeds from the river, but from the source
(a fonte); and this is the reason why they will not concede that the Holy Spirit proceeds
from the Son (quod sit a Filio). Nonetheless, one cannot say that the Spirit does not
really proceed from the Son, who together with the Father forms the single principle
of the Holy Spirit.61
This Wne-shading is repeated in the John Commentary: ‘some of the Greeks
assert that one should not say that the Holy Spirit proceeds from the Son
(procedere a Filio), because for them the preposition ‘‘a’’ or ‘‘ab’’ indicates a
principle which is not from a principle (principium non de principio), and this
only Wts the Father. But this is not compelling, because the Son forms one
single principle of the Holy Spirit together with the Father.’62 So St Thomas
does touch on the narrower meaning of the preposition ek (which is translated
in the Latin here as a or ab). He accurately reports on the meaning
contained in ekporeusis for the Greeks, as relation of origin to the Source,
principle not from a principle. He notices the diVerent or more precise
meaning which the ‘Greeks’ ascribe to the words. One should take this into
account: terminological misunderstanding is not enough to explain the
diVerence between East and West. Thomas does not object to the idea that
the terms can refer the relation to the ‘Wrst point of origin’. But he does contest
the exclusion of the Son, ‘because the Son and the Father together form one
60 CEG II, chs. 15–27.
61 I Sent. d. 12, q. 1, a. 2, ad 3. 62 In Ioan. 15.26 (no. 2065).