One of the most common questions I get at my speaking events is, how can we prove that God is a Trinity? It is also one of the more frequent questions I get on my Facebook and Twitter pages. Here is a slightly expanded version of my answer.
Q: I was talking to a skeptic who wouldn’t subscribe to the possibility of the Christian God being 3-in-1. I gave an analogy of a person being mind, body, and soul, and although this intrigued her, she offered that the mind was actually an extension of the soul. Do you have any thoughts or references that I could access to clarify my position?
A: Most Christian theologians conclude, and I would agree, that it is not possible to separate the soul and the spirit of a human. However, standard Christian doctrine asserts that the earthly body of a human is separable. When a human dies having committed his or her life to Christ, the soul and spirit depart from the body to be with the Lord in heaven. Thus, the body, soul, and spirit of a human is not a good analogy for the Trinity. Every member of the Triune God—Father, Son, and Spirit—have always existed and will continue to always exist.
Your skeptic friend is correct that the mind is part of the soul. Our soul is the sum of our mind, will, and emotions. Our brain is the hardware interface that allows our soul and spirit to communicate with the physical world. When the brain malfunctions, it can distort or cripple the expression of our mind, will, and emotions. This malfunctioning is most noticeable in cases of dementia.
In my book and DVD Beyond the Cosmos, I appeal to extra dimensions to offer better analogies for the Trinity, analogies that do not fall into a modalistic trap. Modalism is the heretical doctrine that avows that God is sometimes the Father but not the Son or Holy Spirit, at other times the Son but not the Father or the Holy Spirit, and at still other times the Holy Spirit but not the Father or the Son. The doctrine of the Trinity states that the Father, Son, and Holy Spirit always exist and are always fully functional as God and yet there is but one God.
The analogies I offer, however, are still only analogies. They illustrate some but not all the characteristics and attributes of the Trinity. Because God transcends the space-time dimensions of our universe and is fully functional independent of the cosmic space-time dimensions, and because our human powers of conception and imagination are limited by the space-time dimensions, it is impossible for us to gain more than a partial description and understanding of the Triune God.
As to how we can better argue for and establish the existence of the Triune God, I have found by experience that one of the best ways is to show people how science makes sense only if God is Triune. One example would be to point out that love is not possible unless there are at least two persons to express and receive love. The problem with strictly monotheistic religions like Islam and Judaism is that a nonloving entity supposedly created beings that give and receive love. How can the lesser create the greater? To put it another way, in strict monotheism, God must create in order to have any possibility of giving or receiving love. If God is a single person, he is unfulfilled until he creates. For the Trinitarian God, creation is an option. It is not a need.
The problem with polytheistic faiths is that the multiple gods possess different creation plans and goals. Thus, in polytheistic religions like Hinduism, there is the expectation that the natural realm will be inharmonious and filled with inconsistencies and unresolvable anomalies. However, centuries of scientific research reveal the opposite. The more we study the record of nature the greater level of harmony and consistency we see and the longer the list becomes of resolved anomalies.
Science, therefore, establishes why God in some sense must be uniplural, as the Hebrew word for God (Elohim) used in Genesis 1 implies. The uniplurality of God also explains why both singular and plural pronouns are used for God in Genesis 1:26–27.
One question that remains is why three Persons and not two, four, or more. Both creation and the redemption of billions of humans reveals a division of labor that points to three Persons. Also, John in his first epistle explains that God’s spiritual light in the world has three components: life, love, and truth, wherein the Son takes responsibility for bestowing life, the Father takes responsibility for bestowing love, and the Holy Spirit takes responsibility for bestowing truth.
Psychologists point out that when two people isolate themselves from the rest of humanity, they frequently become codependent in their relationship. A third person breaks the codependency. This need for three persons is illustrated in marriage. The bride and groom unite to become one, where the bride and groom become an ezer (essential military ally) for one another. However, for this alliance to truly build an increasingly loving relationship and an increasingly productive ministry, the married couple must completely embrace God as their ezer.
In conclusion, the universe, its life, and God’s plan revealed both in nature and Scripture for the redemption of billions of human beings reveals the work of three supernatural Persons who are one in essence, character, purpose, and plan.