Aside from the practical differences and antagonisms that divide religions in our time, there are also some long-standing dogmatic differences that are often relegated to the background, but are quite important.
Catholics and Orthodox have been divided for centuries about the filioque clause in the Creed, concerning whether the Holy Spirit proceeds from the Father alone, or from both Father and Son. Protestants and Catholics have made some headway in overcoming their differences regarding “justification by faith,” resulting after much ecumenical dialogue in a Joint Declaration in 1999, which unfortunately has not yet been supported by many Protestants.
Christians and Muslims are at odds on God’s unity, which seems to completely obviate any possibility of God’s generating a Son. Sura 112:1-3 of the Koran states clearly, “Say: He is God alone . . . God the self-subsistent: who does not beget and is not begotten, and unto whom none is equal.” As Muhammad ‘Abduh’s apologetic for Islam, The Theology of Unity, argues, the notion of an eternal and necessary being seems to be incompatible with plurality or composition of any sort.
Unfortunately, the differences with Muslims on this point are almost unbridgeable, owing to the fact that Muslims understand the “Trinity” as consisting of God, Jesus, and Mary (Suras 4:171, 5:73, and 5:116); and this misunderstanding is further complicated by the fact that Mary, the mother of Jesus, is considered by Muslims to be the sister of Aaron, brother of Moses (Suras 19:28, 66:12, 3:35).
In the doctrine of divine unity of Father, Son, and Holy Spirit, we are in the presence of a great mystery. St. Augustine, according to legend, was walking along the seashore one day, meditating on the Trinity, when he saw a little boy going back and forth from the sea with a ladle, trying to fill up a hole in the sand. When Augustine chided him for doing this, the boy answered that he would sooner fill the hole with the sea water than Augustine would clear up the mystery of the Trinity in his mind. Then the boy vanished.
Adoration of the Trinity by Albrecht Dürer
Augustine, however, was not dissuaded by this vision from continuing his cogitations. He went on to write De Trinitate, consisting of fifteen books; and – short of any full explanation of the mystery – left us with a number of interesting and plausible analogies existing within the unity of the human psyche: He points out the “trinities” within the single human individual of lover, what is loved, and love itself; mind, memory, and will; and mind, knowledge as its “offspring,” and the love of what is known – among other comparisons.
I have found these Augustinian analogies somewhat useful, but lately, in Maria Rosa Antognazza’s book, Leibniz on the Trinity and the Incarnation, I have come across some things that seem to me to improve on Augustine. Leibniz (1646-1716), a philosopher and mathematician, was a Protestant, although much more open than other Protestants to Catholics and Catholic intellectual currents.
It is hard for us to imagine the era in which Leibniz lived – Catholics and Protestants in the midst of multiple scholarly debates about the Trinity. These were major intellectual currents. Socinians, Unitarians, and individual philosophers and theologians were becoming notorious, and sometimes repressed, for their anti-Trinitarian tracts. If TIME magazine had existed then, Leibniz might have been a candidate for “Person of the Year.”
Leibniz’s ongoing participation in these debates is not as well known as his other works. He characterized the anti-trinitarian arguments as akin to deism, that is, belief in a transcendent Being who started everything up, and maybe made sure it continues, but was not a personal God such as Christians believe in. Leibniz includes Islam as a form of deism (this was not pejorative, since he understood deism as a rational position, supporting a natural monotheistic religion, which could prepare the way for the supernatural revelations of the Christian faith, including the Trinity).
Leibniz’s defense of the Trinity was partly historical, the doctrine had a pedigree from the Patristic age through the Christian tradition for centuries. But his main arguments carry Augustine’s analogies one step further. The focus is on self-consciousness. Since self-consciousness is the most spiritual function of human life, and arguably the aspect of human nature that most decisively distinguishes us from the animals, it may provide us the best analogy we have for a living God, who is pure spirit.
As we reflect on ourselves in self-consciousness, we are generating an image of ourselves; the image may be relatively true or false; we may either be satisfied with the image, loving it to some extent, or dissatisfied.
With God, “relatively” and “to some extent” are not applicable. God, whom Aristotle describes as pure immaterial “self-thinking thought,” generates the absolutely true and complete image of Himself, and loves it without reservation. The image generated is identical in nature with the generating Father, and is aptly called the Son; and the love proceeding from this generation is not just some abstract relation, but the eternal identification of Father and Son, it is the spirit they have in common, the Holy Spirit.
Well, I agree: this does not rescue the Trinity from the realm of mystery! But it does help us to realize that the “unity” of God is not like some pure monochromatic undifferentiated disc hovering outside the universe, but the type of spiritual unity-in-distinction accruing to any self-consciousness, and paradigmatically to the absolute self-consciousness of the divinity. And the triune aspects of our own simple act of self-consciousness offer us a stepping-stone to making this supernatural revelation, assented to by faith, a little more understandable.