In Modalism, the distinction between the Father, the Son, and the Holy Spirit are mere "modes" of how a singular, unitarian godhead interacts with creation. Consequently, in Modalism, the Father, the Son, and the Holy Spirit are but one Person with three faces. This would mean that God the Father appeared on earth as the Son and that the Father suffered and died.
Under the orthodox catholic understanding of the Trinity:
- To maintain the three-ness of the Father, Son, and Spirit, they are stated to be three distinct Persons.
- But to maintain the one-ness of God, so that the doctrine does not teach tri-theism (three Gods), the Father, Son, and Spirit, share one undivided divine “nature” or being or substance.
For three reasons, I fail to see the difference between the orthodox Trinity doctrine and Modalism:
Firstly, the notion of divine simplicity, namely that God does not have parts, requires that the three persons are not three parts of God, but that each of them is the full Divine essence. In other words, each of the three Persons is the entire God. This principle may be illustrated by the following formula:
God = the Father = the Son = the Holy Spirit.
This is also stated by the Athanasian Creed when it says:
"So the Father is God; the Son is God; and the Holy Ghost is God. And yet they are NOT THREE GODS; BUT ONE GOD"
Aquinas confirmed: “It cannot be said that the divine Persons are distinguished from each other in any absolute sense; for it would follow that there would not be one essence of the three persons.”
Secondly, in normal English, a person is a self, a thinker, with his own will and mind. But the orthodox Trinity doctrine uses the word "person" in a different sense, for the Father, the Son, and the Spirit share one single mind and one single will.
Relations do not make a difference.
Thirdly, as Aquinas argued, the only difference between the Father, Son, and Holy Spirit is in their relations, namely that:
- The Son is the Son of the Father and
- The Spirit proceeds from the Son (in Western catholic thinking).
To quote Aquinas: “The divine persons are distinguished from each other only by the relations.”
This notion that the only difference is the relations is illustrated by Aquinas’ argument that the Spirit must proceed from the Son, for, he says, if the Spirit proceeds from the Father then the Spirit is the same as the Son because they have the same relation with the Father.
To this we must add that, in the orthodox understanding of the Trinity, the difference in relations has no practical implication:
As Aquinas argued, these relations between persons exist within the divine essence as essential attributes of God, as opposed to “accidental." In other words, there never was a time or situation in which the Son was not the Son and there never was a time or situation in which the Spirit did not proceed. Consequently, always and under all conditions, the Father, Son, and Spirit shared one and the same substance, mind, and will.
According to the Wikipedia page on the Nicene Creed, the Arian controversy began when Arius, a clergyman of Alexandria, "objected to Alexander's (the bishop of the time) apparent carelessness in blurring the distinction of nature between the Father and the Son by his emphasis on eternal generation". (Lyman, J. Rebecca (2010). "The Invention of 'Heresy' and 'Schism'" (PDF). The Cambridge History of Christianity. Retrieved 30 November 2015.)
If this is true, then it is interesting that "eternal generation" was already on the table at this early stage. Arius and the pre-Nicene fathers often claimed that the Son was begotten before all ages and before the creation, but "eternal generation" is a bit more advanced concept, for it means that there never was a time or state of condition when the Father was not Father. Lyman might be guilty of an anachronism.
Nevertheless, my point is that "eternal generation" is another way of saying that the "relations" exist as essential attributes of God. And, as Lyman stated, this blurs the distinction between the Father and the Son.
While some people, in their explanation of the Trinity, emphasize the three-ness of God, often resulting in tri-theism, in the orthodox understanding of the Trinity, the theory that the Father, Son and Spirit 'share' one and the same substance, mind and will, and have always done so, implies that the difference in relation (their origins) is relegated to words with no practical consequence. The emphasis is fully on the one-ness of God. Consequently, I fail to see the difference between the three Persons, in spite of the usual disclaimer that the Trinity doctrine is not Modalism.
On the Got Questions website, which I understand to reflect the Reformed perspective, I found the following statement:
It is quite possible that God does not eternally exist as Father, Son, and Holy Spirit (the ontological Trinity) but that Father, Son, and Holy Spirit explain the way the members of the Trinity relate to us (the economic Trinity).
To me, this seems like Modalism.