Son: Dad? How can God be three in one and one in three? That seems crazy.
Father: Criminy, son. Can’t you ask me an easier question, like how an electron can be a particle and a wave at the same time?
Son: Right now, it’s the Trinity I’m worried about.
Father: OK, I’ll take a shot at it. The first thing you should be clear on is that God is not both three and one of the same sort of thing. That would be like saying that I had three oranges that are one orange, or three lines that are one line. It would be a flat contradiction.
Son: So you mean that he is three in one way, and one in another?
Son: OK. But what are the two ways?
Father: Well, take a string quartet. On the one hand, it’s four men. On the other, it’s the Guarneri Quartet, a single item. Clear?
Father: OK, good. Forget that notion. The Trinity means nothing of the sort.
Son: Great. I guess that would have been the easy way out, huh?
Father: Right. No such luck. But it does give us our first clue. Like the four men of the quartet and the quartet itself, the three Persons of the Trinity are different sorts of things than the One being of God. It’s just that in the Trinity, the Three are not separated from each other into different things, like the men of the quartet.
Son: What are the different types of things in God?
Father: Well, God is one in being – that is, he is one actual thing – in which there are three Persons. The difference is between a thing that has a personal aspect to it, and the person who is the personal aspect of that thing.
Son: I don’t get it. If a thing has a personal aspect, then doesn’t that mean that it is a person?
Father: Not quite. I mean, yes; but there is more to it than that. Think of yourself. There is the person of you, and then there is the thing of you at a given time. The thing of you is more than just the person of you. It is also a sack of fluids, of a certain size and weight, organized in a certain way, and so forth. Sometimes it is sick, sometimes asleep. It might even be in a coma. The person of you is just one aspect of the thing we all call “David.”
Son: I’m not so sure of that. Isn’t the person of me always the same thing as the whole of me?
Father: No. When you were two, you were the same person you are now, right?
Father: Well, does it make sense to say that the *person* of David was three feet tall when you were two, or does it make more sense to say that the *body* of David was three feet tall?
Son: The body, I guess.
Father: Right. You are the same *person* you were then, but you now have almost completely different properties as a *concrete being* than you did when you were two. Just look at you now: a strapping young lad. Back then, you were just a baby in diapers. Not only are you bigger and stronger, but almost all the particles that made up your body at age two are gone. It’s like the difference between an acorn and a mighty oak. The acorn and the oak are not the same thing at all, are they?
Son: No, not really. I suppose you’re going to talk about the caterpillar and the butterfly next.
Father: A good bet. You’re right. Same sort of thing. But then, when you think about it, the same sort of analysis holds between any two moments of your life. What you’ve got with a human person is a single life, distributed across a whole series of different beings, that exist in different places in the universe. I mean, when you think about it, the me and you of right now are many thousands of miles away from the me and you of just a moment ago, thanks to the velocity of the Earth and our Solar System through space.
Son: Right. If we were to go back in time even a minute, we’d find ourselves in outer space.
Father: Yes! The you of right now is in a completely different orientation to the whole universe than the you of a moment ago. Considered in those terms, there’s almost nothing about the you of now that is like the you of a moment ago.
Son: Yet I’m still me. So, OK. What *is* a person, anyway?
Father: That’s a pretty big question in its own right. For the time being, let’s just look at the origin of the word. It comes from the Greek prosopon, by which the Greeks meant “mask.” A prosopon was a mask worn by an actor in a Greek drama, to signify the face of the character he was playing. So prosopon means, not just the literal mask, but also the outward appearance or aspect of a thing, as distinct from its inward substance. The face of a person, then, is in a sense his prosopon. And in fact, one of the things that “person” meant in old-fashioned English of even a few decades ago was appearance, aspect or face.
Son: So are the Persons of the Trinity just three different outward aspects of the one God?
Father: No. God does have different appearances to us creatures, depending on our situation; but the Persons are not “nothing but” those different appearances. That’s actually a pretty serious heresy, called modalism.
Son: Well then, why does the Church use the word “person” for the Trinity?
Father: Let’s dig deeper into the word. Prosopon is made up of two parts. First is the prefix pro, which stands for a bunch of different things: at, near, by, to, towards, with, with regard to; so, our nearest English equivalent is probably “for.” Second is the word ops, which also means a bunch of things: to see with the eyes, to perceive, to experience, to know, to beware, to care for or take heed of, and so forth. These are its primary meanings. Only secondarily does it mean what we take it to mean when we think of an actor’s mask: to be seen, to show oneself, to appear. And that this meaning of “appearance” is secondary makes sense: only if you are angry on the inside, for example, are you likely to appear angry on the outside.
Son: So, prosopon means …?
Father: Well, it seems to mean something like, “thing for seeing with the mind, for perceiving or knowing.” And then it also means, “thing for appearing or showing oneself.”
Son: I look out through my face, or with my face – and my face looks like the sort of person who is looking out through my face, so that if I am looking out while feeling angry, the face I look out through is likely to look angry to other people.
Son: So a person, like a face, is a thing for seeing the world – a thing that sees, and knows, and experiences. And, like a face, a person looks to others like the sort of things that it sees in the world. It puts out to the world what it sees.
Son: So to an angry person, the world looks angry. And if the world looks angry to you, you are probably going to feel angry yourself; and so then you will look angry to the world. Same with a happy person, or a sad person, or a really excited person.
Son: So the person of me is the one who is seeing the world, reflecting back what it sees.
Father: Yes. And the way that the David of today and the David of twelve years ago can be the same person, even though those two Davids are quite different things, is that the person of David is a certain consistent way of looking at the world, that is just yours. Every parent has seen this. A child of two has the same basic attitude toward the world as that same child at eight, at ten, at twenty.
Son: So that’s how my person is consistent from before birth to right now. I can see that. Things have happened to me that have changed parts of my attitude to the world. I’m older and less innocent. Some pretty bad things have happened to us, and that has changed my idea of what sort of place the world is. But I still feel basically the same way about things. I’m still me, and I recognize in myself today the me that I remember from when I was little.
Father: Me, too. One way of thinking about it is that the you of today includes everything of the yous of all your yesterdays.
Son: I see. That’s just a different way of saying that I am the same as the boy of the Burrito Incident. [smiles in happy recollection] That boy is the same as me. He is inside me.
Father: [chuckles] Right. You are the same person, appearing in lots of things over time. Each of those things is subtly different from all the others, but what they all have in common is the person of you. The boy who laughed so hard during the Burrito Incident is here right now, even though his body is gone, along with the Incident.
Son: What about God?
Father: You are one person in many things. God is three Persons in one thing.
Son: OK. You say the words, but I don’t see what they mean. How can you have three Persons in one thing? Why only one thing?
Father: Well, it’s only one thing with God, because if there were more than one thing that was God, that would raise the question which one was superior. And that one would be the only one we could call God, properly speaking, because the others would be dependent upon it.
Son: All right, so God has to be one thing. How can you have three persons in one thing? I know it isn’t like the string quartet.
Father: Right. It’s like the person that is you today, that includes the you of yesterday, and that includes the you at the time of the Burrito Incident. The you of today includes those other yous, but not in the way a box contains a ball or a collection of fruit includes an apple, nor in the way that a computer includes a CPU and some RAM. The you of now includes the you of yesterday by knowing him and reiterating him – doing him over again, albeit with some additions. The you of yesterday is in the you of today, not like the yarn is in the basket, but more in the way that the basket of yesterday is in the basket of today. If the basket had been stained yesterday, then the basket of today would be stained, too.
Son: OK. I think I see. And the basket of day before yesterday, that was not yet stained – that’s in the stained basket of today.
Son: And that’s how the Son includes the Father, and the Father includes the Son. And it’s the same between each of them and the Holy Ghost.
Father: Correct. Now, with you, there can be one person that includes lots of things. But with God, all those inclusions have to be within one thing. So the Divine Persons are all within one thing. Each of the Persons includes both the others. But their relations of inclusion are all within the one thing that is God.
Son: Why is there more than one Person in God? Why are there inclusions in God?
Father: Well, if God were just one Person, he wouldn’t be able to know anything about himself. He would just be, and would know everything *except* himself. That seems like a silly idea. It seems that in order to be the ultimate being, he would have to know everything. And to be omniscient, he would surely have to know himself, too. So he has to look at himself. And that can only be done by a person, a thing for looking or knowing. So the Father has to have a Son, a mind who knows the Father, and is the perfect image of the Father. Then the Father, in knowing the Son, would automatically know what the Son knows of the Father. So that way, the Father could know himself.
Son: What about the Holy Spirit?
Father: Well, just as the Father needs to know himself in the Son in order to know himself at all, so the Father and the Son need to know their knowledge of each other as it is known to a third, in order to know that knowledge themselves. The Son is the Father’s way of knowing himself. The Spirit is the way that the Father and Son know that they know each other.
Son: OK, so let me see if I get this. First there is the Father, and then there is the Son who knows the Father, and then there is the Holy Ghost who knows the Father and the Son knowing each other.
Father: Right, except for one thing: the word “then” should not appear in that sentence.
Son: How come?
Father: Because God is one single thing. He is all at once. The Father is not wholly the Father without his knowledge of his Son’s knowledge of him, nor is he fully the Father without his knowledge of the Holy Ghost’s knowledge of the relationship between the Father and the Son. So, it is not as though there was a time for a while when there was only the Father, without the Son or the Spirit. No, you can’t get the Father at all without getting the Son and the Spirit. It’s a package deal. So all three Persons are eternal, and equal: you can’t have any one of them without having all three.
Son: OK. So there is one being, God, and he has three different things for knowing, three different things that know. Does that mean that the Persons are three different minds?
Father: I think it does, yes. There are three minds in the one being of God.
Son: Thanks, Dad. I think I understand.
Father: You don’t. I don’t, either. We understand our own concepts, maybe. Maybe. That’s a very different thing than understanding God. At best, all we have done here today is clear up the confusions created by our own use of language. But once you’ve cleared away all the conceptual confusions that get in the way of seeing God, you still have to turn and look at him yourself – you have to get your prosopon in gear.
There is in God, as there is in us, a sort of ‘circulation’ (circulatio) in the operations of mind and will: for the will returns to that which understanding initiated. But with us the ‘circle’ (circulus) closes in that which is outside of us: the external good moving our intellect, our intellect moving the will, and the will returning through its appetite and love to the external good. But in God, the ‘circle’ is completed within himself: for when God understands himself, he conceives his Word which is the ‘rationale’ of everything known by him, since he understands all things by understanding himself; and through this Word, he ‘proceeds’ to the love of all things and of himself . . . And the circle being completed, nothing more can be added to it: so that a third procession within the divine nature is impossible, although there follows a procession toward external nature.
–St. Thomas Aquinas, De potentia, q. 9, a. 9.