We’ve all the heard one about the three-lobed shamrock and the Trinity.
But it turns out that God’s triune nature is imprinted on all creatures, according to two of the greatest doctors of the Church in the 1200s—St. Thomas Aquinas and St. Bonaventure.
In the Summa Theologica, Aquinas says that all creatures with an intellect and a will reflect the Trinity:
For the Son proceeds as the word of the intellect; and the Holy Ghost proceeds as love of the will. Therefore in rational creatures, possessing intellect and will, there is found the representation of the Trinity by way of image, inasmuch as there is found in them the word conceived, and the love proceeding.
Aquinas on the image of the Trinity in creation
Aquinas here is standing on the foundation laid by St. Augustine in his masterpiece, De Trinitate. Augustine proposes that we can understand the Trinity by way of analogy with ourselves. By looking within, we can see the image of God reflected, which can become a means of knowing God. Augustine understands the Son as proceeding from God as His self-understanding, or Word, to use the biblical term as Aquinas does. The Holy Spirit is the mutual love shared between the Father and the Son. (Love is associated with the will because love is willing the good of the other.) To the extent that we have an intellect and will, then we reflect this Trinity. ….