A major problem in understanding the doctrine of the Trinity is that it is expressed in philosophical terminology that was well understood by educated people of the fourth century AD but is rarely understood today. Making the matter even more complicated is that these terms are often translated into English using words that have an entirely different meaning in common use. Thus, the doctrinal assertions are wide open to confusion among its supporters and caricature among its detractors.
In this post, I will try to give some basic understanding of the terminological definitions so that a proper meaning can be given to the doctrine. At this point, I will not be giving a Biblical defense of the doctrine – that will come in later posts. For now, I think it is important to first explain what is being defended and then moving on to deriving the doctrine from the pages of Holy Scripture.
As already mentioned the doctrine is expressed in philosophical terminology common to its time but some of the terms are translated using common words with misunderstandings as to what meaning is being conveyed. For example, terms that arise such as “substance” and “person” have technical meanings within the philosophical expression of the doctrine that are confused by their everyday use. When expressions of the doctrine speak of God being “three persons within one substance”, it does not mean what you would normally think of as a person or a substance.
Then there is the matter of the technical terminology itself. First of all, the Greek philosophical term “ouisa” (“essence” or “substance”) is the defining nature of that which is under discussion. That is, it is what makes something what it is. When we speak of the Triune God, it must be emphasized that there is only ONE essence. Hence there is only ONE God. If each of the three divine persons had their own essence, then that would be tritheism. That is definitely not the case here and those who claim the doctrine of the Trinity is a form of polytheism are hence either ignorant of the doctrine or are willfully dishonest.
Next we turn to the three persons. Part of the difficulty here is that there are two philosophical terms in Greek, both playing a role in the definition, and both are often translated into English as “person”: the first is “prosopon” and the second is “hypostasis.” The precise technical defintion of each must be properly understood as well as its role in setting the limits of the doctrine.
The term “prosopon” was derived from the Greek theatre where masks were used to identify the character and their emotional state. In philosophy, it can be considered the manifestation under which the essence is revealed. The term “hypostasis” refers to an underlying property of something. Both can be used in to describe aspects of the Trinity but either can be confusing when not understood properly in the context of the doctrine. It is the flexibility of these terms that makes it important to emphasize the contextual restrictions.
Problems occur when the terms are not understood within the context of the discussion. Prosopon is insufficient on its own because it does not rule out the manifestations being used and shed according to the situation. That is, God could be the Father in one situation and the Son in another and the Spirit in yet another but these are roles God plays and do not correspond to something within the essence of God. Such a description is the early Christian heresy of Sabellianism (also called modalism) wherein the three persons are seen as modes of God’s existence in differing contexts. The problem with hypostasis is that it could be used to refer to an underlying reality in the general sense and hence could be confused with essence or it could describe an underlying reality of a specific essence which in the case under discussion would be the three divine persons.
In the early Ecumenical Councils, they resolved the difficulty by using hypostasis but specfying in was three hypostases of one essence and hence ruled out the problemmatic interpretation of hypostasis. Thus the three persons are three hypostases that may be thought of as manifestations of God but cannot be thought of as merely contextual manifestations. The Three persons, rather than being modes in which God is manifested, are of the very nature of the divine essence. There is one divine essence which by its nature has three hypostases which each are manifested to us as individual prosopon.
The next question deals the terms Father, Son, and Holy Spirit. The doctrine speaks of the Son as eternally begotten of the Father while the Holy Spirit eternally procedes from the Father. The term “begotten” and “precession” are to be understood in terms of eternal relations between the persons of the Trinity and not as events occurring in a specific temporal frame. That is, all three persons are coeternal and coequal with the Father as the source relationally and with respect to authority. There has been a split on the precession of the Holy Spirit between East and West, with the latter adding the Holy Spirit proceeeds from both the Father and the Son, but the defenses by both Protestant and Catholic apologists make clear they have a different concept of precession in mind than that discussed at the Councils.
It should be noted that while the three divine persons are all coeternal and coequal with respect to their divinity, there still exists a relational hierarchy in which the Father is in some sense the “source” of the Trinity. The full understanding of this and other divine properties are reserved to the Council of God and we may not fully understand them this side of eternity. Often those criticizing the doctrine deride this limitation as they assume we should be able to comepletely comprehend the divine nature. It never occurs to them that such a comprehension only illustrates that what they have in mind cannot be God but only the preference of the corrupt human will.
The battles over Trinitarian theology in the first two Ecumenical Councils would also result in battles over Christology in later councils. The question then became when the Son, the Second Person of the Holy Trinity, became incarnate, what was the nature of the union between His divinity and humanity. One position stated that the union was at the level of prosopon, as a human manifestation, but at the level of hypostasis, the divine and human remained distinct. This would imply that Christ was in fact two persons, one divine and one human, manifested in a single human form. Others went in the other direction and insisted there was one divine person whose human nature was subsumed into his divine nature. The Church took a middle view condmening both the first idea, called Nestorianism, and the second, called Monophysitism, for the view that the person of Christ was one at the level of hypostasis where He remained both fully divine and fully human. This definition, called the “hypostatic union”, remains the orthodox definition of the nature of Christ.
This latter point leads to some critics of the doctrine claiming it is contradictory as the term hypostasis appears to have two different uses in the orthodox Trinitarian and Christological defnintions. Here they claim Christ is one hypostais in the first and two in the second. However, those making such claims fail to grasp that the term “hypostasis” is always relative to a context. In the first definition, the context is the persons of the Godhead and that the triune nature is of the underlying reality of the nature of God. In the second definition, we are not speaking of the person of Christ but of his incarnation and the union of two natures. Here we are not describing the underlying reality of the Godhead but of the incarnate Son of God.
The above gives an outline of the doctrine of the Trinity with its terms defined correctly. Having properly defined the doctrine, we can later discuss whether or not it is found in the Bible. I happen to believe it most definitely is found there and all the arguments against it have either misinterpreted the passage, used faulty understandings of the New Testament Greek, or were using “strawman” definitions of the Trinity. We can now turn to how the doctrine was derived and defended.