This is one in a series on the Christian doctrine of the Trinity. To see MRM’s website page on the Trinity to see other resources, please click here.

By Eric Johnson

Many people reject the Trinity because they believe it is a concept that cannot be understood. “Shouldn’t God be understandable?” is a question already answered in the minds of most who ask it. There are several possible questions you can ask in response to this question:

1. Ask, “Why do you think finite humans should be able to fully understand God and His nature?” After all, if He is eternally God and has infinite knowledge, and if humans are created and will have finite knowledge, shouldn’t we expect that God’s understanding is much higher than ours? Isaiah 55:8-9 says, “For my thoughts are not your thoughts, neither are your ways my ways, declares the Lord. For as the heavens are higher than the earth, so are my ways higher than your ways and my thoughts than your thoughts.” While God certainly provides many ways for us to understand Him, it makes sense that He is not meant to be fully understood by sinful human beings.
2. Ask, “Is your spouse (or boyfriend/girlfriend) understandable?” I have been married for more than a quarter of a century and love my wife very much. However, I will admit that there are things about her that I just don’t always understand! This woman of mine has a sense of humor and admits the same for me, such as her not understanding how I can watch three football games in a row on a sunny Sunday afternoon! No matter how much we understand another person, there is always going to be a mysterious element to him or her. (If you suggest there is no more mystery and you fully comprehend your wife, then she is fully predictable and your relationship needs some more spice!)
3. Ask, “Can you explain eternity?” There are only two possibilities: either matter has always existed or it has not always existed (and needed to be created). If matter has always existed, then how did we ever get to today? A philosophical argument called the Kalam Cosmological Argument shows the impossibility of actual eternal matter. The three-part syllogism goes like this:
   1. Whatever begins to exist has a cause.
   2. The universe began to exist.
   3. Therefore, the universe has a cause.

If matter has not always existed, then how did we get here today? Logic says, “Out of nothing nothing comes.” A critic may ask, “Where did God come from?” The answer is that he didn’t need a beginning because He is self-existent and, by definition, doesn’t need a cause. God has always existed. He created time, matter, and energy, as He preceded matter. (God is spirit, John 4:24 says.) The point is that eternity is certainly a mysterious matter, and even though it goes beyond explanation, most people believe it is true. For the Mormon who wants to be able to logically present a material God of flesh and bone (D&C 130:22), we ask, “Could you please explain how God (who was once a man in another world) became God? And can you give me the name of the God who was before him? Who was the first God?” Latter-day Saints usually retreat into this same “mystery” camp that they criticize Trinitarians for camping in, yet they still believe the LDS concepts are true even though they can’t explain them.

4. Ask, “What does one and one and one equal?” I’ve used this illustration many times and the answer is always, “Three.” And, yes, this is a correct answer if I’m talking about addition. But multiply one and one and one, and what do you get? Despite the fact that there is no subtracting, the answer is one. Three numbers, two different answers. There is something called the “mystery of math,” as even the most astute mathematicians contend that not everything–including mathematics–can be understood. (A favorite math mystery is Hilbert’s Hotel, which helps explain William Lane Craig’s description of the Kalam Cosmological Argument.)

5. Ask, “If you fully understood God, would you not, in essence, become God yourself?” Think about it. The Bible describes God as transcendent (above our thoughts, as quoted above in Isaiah 55), which means that He cannot be fully understood. But suppose someone could grasp the very essence of God and His nature, the God who is “omni-everything.” If that was the case, then such a person must have perfect knowledge and is certainly omniscient (all knowing). To admit a lack of omniscience means that the person cannot (and never will be able to) fully understand God.