The Trinity is at the heart of the Christian Faith.
We Christians believe that God is the Father, the Son, and the Holy Spirit. We do not believe in three gods. Like our Jewish ancestors in faith, we are monotheists, who hold only to One True God.
But each Person of the Trinity is truly distinct. The Father is not the Son and the Son is not the Father and neither are the Holy Spirit. And yet even though they are Three Persons, they are still only One God.
To say that this is difficult to understand would be an understatement. In fact, it is impossible to understand. That is because this is one of the three great mysteries of the Christian faith (the other two being the Incarnation and Salvation). A mystery is something that is beyond human comprehension. It is not that the subject of the mystery is irrational or contradicts reason. Instead, a mystery is something that is so infinitely profound that it cannot possibly be encompassed by our limited human intellects.
Very often, people try to explain the Trinity using analogies. They look for common examples that people find familiar and transpose that to the mystery of Trinity. The most famous story fo this is St. Patrick and the shamrock. The story goes that Patrick was having trouble getting the pagan Irish to understand the Trinity. But then he picked up a shamrock and showed it to them. He pointed out how it was three leaves but also one leaf. In that way, the Irish people could see three and one existing in the same substance and thus became open to the concept of Trinity.
Now as wonderful as that story is, we have to be careful that we don’t confuse the analogy with the mystery.
I’ve often had to teach about the Trinity and the temptation is often to oversimply things so that my students can wrap their heads around it. The human mind is very uncomfortable with things that it cannot understand. I can see some of my students become cynical and dismissive. They want to write off the Trinity as a superstitious holdover of a bygone age. So to draw them in, I like using analogies because they are then able to see how some of the truths of the Trinity could be real.
The problem is that all of the analogies break down. And they break down pretty quickly.
For example, the Shamrock analogy ultimately doesn’t work because it implies that each Person of the Trinity is one-third of the whole, which is not the case.
When I was in high school, one of my teachers said that the Trinity was like H2O. It is one molecular substance. But we experience it in three radically different ways: as water, as ice, and as vapor. I have also used this analogy because it is very concrete. I take a bottle of water and I hold it over a student’s head. I ask them what will happen if I empty the contents on the bottle on head. They reply that they will get wet. When I ask them if it will hurt, they tell me “no.” But then I grab a bottle of water that I left in the freezer over night so that it is a solid block of ice. I ask the student if it would hurt if I emptied the contents on the bottle on their head and they say “yes.”
“But,” I respond, “Didn’t we just establish that dumping H2O on your head wouldn’t hurt?”
They respond, “But that was water. This is ice!”
“Yet it is still H2O, isn’t it? It hasn’t changed its molecular composition?”
“So ice is not water and water is not ice, but they are still one thing: H2O.”
I can see my students eyes light up as they think they begin to understand. But I am quick to point out that the analogy breaks down. This analogy could give the impression that each Person of the Trinity is just another way to experience the same being. In other words, these are just different names for the same substance. But this is not the case. As stated earlier, the Father is not the Son and neither are the Holy Spirit.
The temptation with teaching analogies like these is that they reduce the mystery into a digestible and understandable example that does not challenge the mind too much. But the true mystery should cause the mind to stretch and reach and ultimately come to the place where it has to accept Trinity not as a concept that has been demonstrably been proven, but as belief to which you surrender in faith.
The Athanasian Creed sums it up beautifully when it says:
That we worship one God in Trinity and the Trinity in unity,
neither blending their Persons
nor dividing their essence.
For the Person of the Father is a distinct Person,
the Person of the Son is another,
and that of the Holy Spirit still another.
But the divinity of the Father, Son, and Holy Spirit is one,
their glory equal, their majesty coeternal.