Trinitarianism and Modalism
The doctrine of the Trinity is often confused with a view of God known as Modalism and even the most astute Trinitarians can be found inadvertently promoting Modalist beliefs. To many people, Modalism can appear very similar to Trinitarianism. There are various forms of Modalism. Modalism is also sometimes known as Sabellianism and colloquially known as "Oneness Theology" and sometimes "Jesus only."
In Trinitarianism, the Father is not the Son and the Son is not the Father. However, in Modalism, the Father is the Son and the Son is the Father. In Trinitarianism, God is not one person but three persons. However,in Modalism God is one person and not three persons. God is one person and that one person is Jesus and Jesus is the Father and Jesus is the Son and as such is God who manifests himself differently in these ways. In this belief system, the three distinctions of God are not personal distinctions of one being but functional distinctions of the one and same person. Hence, the distinctions of "Father," and "Son" are different functional "modes" of being of the same person.
I ran across a website the other day where a lady wished to defend the Trinity. She used an analogy to describe her belief and explained that although she is one person, she is a wife and a mother and a daughter. She was completely unaware that her analogy was promoting simultaneous Modalism which is considered heresy among Trinitarians. I ran across another website which indicated that God had manifested himself in three different ways throughout history, first as Father, then as Son, and now as Holy Spirit. This is not Trinitarianism but successive Modalism, another concept considered to be heretical by Trinitarians.
In Modalism, God is one person who is manifested in different modes or functional offices such as Father and Son. This confusion is common even within Trinitarianism. It is not uncommon to find trained Trinitarian theologians talking themselves waist deep into Modalist waters in efforts to explain their own Trinitarian doctrine. The reason this confusion exists is that both Trinitarians and Modalists can, and do, say the one God is manifested, or expressed, in three different ways, three different distinctions. The Trinitarian modes are the modes of three distinct persons of the one God, while the Modalist mode are the modes of three distinct "functions" or modes of being of the one God. When examined closely, Modalism and Trinitarianism essentially differ in one simple aspect. The Modalist believes in one person manifesting as three distinct beings. The Trinitarian believes in one being manifesting as three distinct persons. If a person was to equate the concept of "being" and "person" there is then no real difference between the two. However, this is where the hair-splitting begins. Modalism was actually the first concerted philosphical attempt in church history to try and explain the relationship between Father, Son and Holy Spirit and the breeding ground for what later became Trinitarian theology as a reaction to Modalism (Arianism was also a reaction to perceived Modalism). The Modalist Supreme identity is one person. The Trinitarian Supreme identity is one being but three persons. The Modalist Supreme identity is manfested in three functional offices, Father, Son, Holy Spirit. The Trinitarian Supreme identity also functions as three distinctions, Father, Son, Holy Spirit. It is very interesting to compare Modalist and Trinitarian statements and one finds each of them often dipping into each other's theological candy jar when it becomes necessary for them to do so. The doctrine of the Trinity does not, on one hand, assert that three persons are united as one person, or three beings in one being. The doctrine of the Trinity does, on the other hand, assert that three persons are united as one being, or one being as three persons. In each case, Modalists and Trinitarians are trying to preserve the idea that God is one identity or one individual without getting caught in a false teaching.
The important thing to remember here is that Trinitarians vehmently reject Modalism as heresy. When Trinitarianism is challenged one must be sure that one is not really objecting to Modalism and this is a very common mistake. However, one must also be reminded that Trinitarians very often misrepresent Modalists due to either ignorance or simply an overzealousness to assault their belief system. And very often Modalists do the very same thing to Trinitarians. Modalism does not have a very wide following and is mostly confined to distinct groups within pentecostalism such as the United Pentecostals (the majority of other Pentecostals, such as Assemblies of God, are Trinitarians).