Water goes through those three states: solid (ice), liquid (water) and gas (steam). All matter does, in fact, it’s just that water does it at temperatures that we can observe easily. Carbon dioxide, one of the major gasses in the air we breathe, turns into a liquid at about -57 degrees Centigrade and a solid at about -78, so it’s not something we see normally. So water it is.
It all starts with the question "at what temperature does water boil, and become steam?" In other words, at what point does the liquid become gas? (100 C) At normal atmospheric pressure, it's 100 Celcius or Centigrade, 212 Fahrenheit or if you’re really being scientific 373.15 Kelvin. We’ll stick with Centigrade for today. However, early on physicists noticed that if you changed the atmospheric pressure, by going up a mountain, for example, the temperature at which water boiled changed. It got less. Which was an interesting discovery but actually made a worse cup of tea. If you plot this on a graph you get (...), known as the Steam Line. If you're this side of the line, you've got steam. If you're this side of the line, you've got water. If you're on the line, you've got a steady state: water and staem co-exist: neither changing into the other.
You can do the same thing for the freezing point of water, when liquid becomes vapour. Plotting this on the same graph gives you (...), known as the Ice Line. Here you've got ice, here you've got water, here you've got steam. On the lines you've got steady states where two states exist at the same time, neither changing into the other.
It is possible to go straight from ice to steam, without passing through the water stage first. You’ll probably be most familiar with that phenomenon with Carbon Dioxide, used as dry ice in concerts and theatre productions the world over, where solid CO2 is used to suddenly turn into vapour and create this wonderful carpet of fog lying on the floor. Phantom of the Opera uses this effect to make it look like you’re on a lake. Rock stars use it to hide their dodgy footwear. Although when Graham Bonnet joined the Micahel Schenker Group he wrote out all his song words and left them on the floor. It worked fine in rehearsal. Come the concert and they switched the dry ice on – he couldn’t see any of them. He only lasted the one gig.
Anyway, if you plot that line, the Horfrost Line, on the graph you get (...). If you extrapolate these lines, to see what they point at, you discover that they meet up, at a temperature of 273.16 degrees Kelvin (that's 0.16 Celcius) and an atmospheric pressure of 4.6 mm Hg (normal air pressure is about 29-30). This point they called the triple point of water. It's the point at which ice, water and steam all co-exist. You may say "that's easy". After all, if you boil a pan of water & then throw in some ice cubes, you have all three at once. Except that it doesn't stay that way. Come back after thirty minutes and you've got a steam-filled kitchen and a ruined saucepan.
The triple point of water exists only at this one point. It's a stable state at which water, ice and steam all co-exist. If the temperature moves only 0.01 degrees to 273.15, the whole lot freezes.
However, all we've done here is to establish a theory by joining up some lines on a graph. Actually proving that theory by producing ice, water and steam in steady state is a different matter. After all, I wouldn't want you to think that all us research Physicists do all day is dot-to-dot.
When I first heard about the triple point of water, I didn't believe it was possible. I couldn't get my head round how this could be true: which is many people's reaction to the concept of the Trinity. Once I'd been convinced that it was possible (mainly by being shown the experimental apparatus to produce it), I then asked myself what the point was: again, many people's reaction to the Trinity.
The doctrine of the Trinity is not found explicitly in the Bible. There’s no one passage of the Bible you can read that says it exists nor that explains how it works. But, like the triple point of water, lots of things point to it and so we can extrapolate in order to understand.
The word "Trinity" never appears and, although used by Tertullian in the last decade of the 2nd century, it wasn't until the 4th century that it found a place formally in the theology of the Church. Scripture does not give us a fully formulated doctrine of the Trinity, but it does contain all the elements out of which theology has constructed the doctrine. All the pointers, if you like.
Much in the same way that physicists joined up the lines to establish the concept of the triple point of water, without ever having seen it, the Bible doesn't tell us that the Trinity exists, but it gives us plenty of hints for theologians to fill in the blanks. Unfortunately, theologians have a habit of filling in the blanks by saying things like: "The definition of the subsistence of God is in stating that God is one in His essential being, but that the divine essence exists in three modes or forms, each constituting a Person, yet in such a way that the divine essence is wholly in each Person." This has led many people to believe that all theologians are filled with the Holy Spirit as they're always talking in strange languages.
So let’s look at these pointers, and see where they join up.
The doctrine of the Trinity is derived from various references in the Bible. In Genesis 1v1-3 God is seen to create by means of Word and Spirit. Hence, from almost the word go, the Word is portrayed as a personal creative power, and the Spirit as the bringer of life and order to the creation. There is therefore a threefold centre of activity: God as Creator thought out the universe, expressed His thought in a Word, and made His Spirit its animating principle, thus indicating that the universe was not to have a separate existence apart from God or opposed to Him. Genesis 1v26 further compounds the image as God says: "Let us make man in our image, in our likeness".
The threefold source revealed in creation becomes still more evident in the unfolding of redemption through the Old Testament. The revelation of redemption was entrusted to the mal'ak Yahweh, the messenger of God, sometimes referred to as the Angel of the Covenant. It is clear that in passages such as 2 Samuel 24v16 (an angel that brings God's judgement on David for counting Israel), 1 Kings 19v5 (an angel who tells Elijah to get up & eat) and 2 Kings 19v35 (an angel who destroys the Assyrians besieging Jerusalem) the reference is to a created being invested with divine authority for the execution of a special mission. However, in other passages such as Genesis 16v7 (the angel who sends Hagar back to Sarai), 24v7 (the angel who goes before Isaac when he's hunting for a wife) and 48v16 (the angel who delivered Jacob from harm) the mal'ak Yahweh not only bears the divine name but has divine dignity and power, dispenses divine deliverance and accepts homage and adoration proper only to God. From the way other angels refuse to accept such worship, it is clear that this messenger is something else: part of the Godhead.
The Spirit of God is also given prominence in connection with revelation and redemption, and is assigned His office in the equipment of the Messiah for His work (Isaiah 42v1 ("I will put my Spirit on him and he will bring justice to the nations"), 61v1 ("the Spirit of the Lord is upon me, because the Lord has anointed me to preach good news to the poor")). The Spirit is also assigned His office in the equipment of God's people for the response of faith and obedience (Joel 2v28 ("I will pour out my Spirit on all people" - the passage Peter quotes at Pentecost), Isaiah 32v15 ("Til the spirit is poured upon us from on high"), Ezekiel 36v26-27 ("I will put my Spirit in you")). Thus the God who revealed Himself objectively through the Angel-Messenger revealed Himself subjectively in and through the Spirit, the Dispenser of all blessings and gifts within the sphere of redemption.
The hints continue in the New Testament, where we see the Spirit and the Father clearly at work at the incarnation. Mary is told that she will become pregnant when the Holy Spirit comes upon her and the power of the Most High (the Father) overshadows her. At Jesus' baptism He is given the witness of the Father (who speaks from Heaven) and the Spirit (who descends to Him as a dove). Jesus is given the authority to baptise with the Holy Spirit. From John the Baptist's teaching it appears that he recognised that the Holy Spirit would come from the Messiah, not merely with Him. (Also to be found in John 15v26 ("When the counsellor comes, whom I will send to you from the Father")). The third person of the Trinity was thus the Spirit of God and the Spirit of Christ. As the Spirit of God, which was one with the Father, and the Spirit of Christ, who was one with Christ, were the same person, it follows that the Father and Son are one with each other. QED, as us mathematicians like to say.
The baptism mentioned in Matthew 28v19 (part of the great commission) is into the name of the Father, and of the Son and of the Holy Spirit.. The expression is a Hebrew one, rather than Greek, and would seem to be into one name, not three.
In Mark 2v5-7 we see Jesus forgiving sins which, as his critics rightly observe, only God the Father can do.
The formulation of a doctrine of the Trinity, as I said earlier, did not come about until much later. To a large extent the Church was forced to develop it as a way of explaining its belief in the deity of Christ. This was done at the council of Nicea (AD 325), receiving a formulation by Augustine a century later, then a further elucidation by Calvin from which it passed into the body of the reformed faith, from which the Church of England grew.
So, having seen where it comes from, what is it? In basis, the doctrine of the Holy Trinity is this (and I'm afraid this is all a bit theological): God is One in His essential being, but in this being there are three Persons, yet so not as to form separate and distinct individuals. "Person" is not a very good term, however, as it implies separate rational and moral individuals. In the being of God there are not three individuals, but only three personal self-distinctions within the one divine essence. Each Person in the Trinity is self-conscious and self-directing, yet never acting independently or in opposition. When we say that God is a trinity in Unity, we mean that there is unity in diversity, and that diversity manifests itself in Persons, in characteristics, and in operations. Moreover, the subsistence and operations of the three Persons are marked by a certain order, involving a certain subordination in relation, though not in nature. The Father as the fount of deity is First: He is said to originate. The Son, eternally begotten of the Father, is Second: He is said to reveal. The Spirit, eternally proceeding from the Father and the Son, is Third: He is said to execute. While this does not suggest priority in time or in dignity, since all three Persons are divine and eternal, it does suggest an order of precedence in operation and revelation. Thus we can say that creation is from the Father, through the Son, by the Holy Spirit.
That's the theological viewpoint. The question is though, is it important? Well, yes. It is important that when we worship Jesus, we worship the Father. It is important that when we follow the prompting of the Spirit, we follow Jesus' prompting. It is important that when we ask the Father to draw near, we ask for the Spirit to draw near. In truth, these things would happen anyway. The Trinity exists, whether or not we know about it. Just like the triple point of water exists, whether we’re physicists or not. However, I think it is not only important that these things happen, but that we know that they happen.
The scientific use of the triple point of water is that it is a reference point. Science relies upon the reproducibility of results. In other words, it doesn't believe things unless you can do them again. Much like winning football trophies: you team's no good unless it wins more than one. Or two. With the triple point of water as a reference point, you can accurately state the conditions under which you changed sand into gold, created artificial intelligence, refracted light into 9 bands etc. so that others can do it and agree that your discovery is correct.
But before I conclude, a quick heresy spoiler. I’ve use the triple point of water as an illustration of how you can use things you know to point to things that are true. Please don’t go home thining that the Holy Trinity is like water, i.e. sometimes it’s the Father, sometimes it’s the Son, sometimes it’s the Spirit. That’s modalism and is a well-denounced heresy. The Trinity is more like the triple point itself: all three at once and it all depends on which bit you’re looking at as to what you see.
It is important to know such reference points, but it is more important to follow on from the foundations, to act according to the things we know because the cornerstone is there. Once in a while, though, it's good to come back and remind ourselves of the foundation stones on which our faith and our redemption are built. The whiteboard in my office currently displays a proof of the Bessel correction (that says you divide by n-1 instead of n to get the standard deviation of a sample), something that most people just use. But I like to know not just that it works, but why it works. Like the triple point of water which helps us to explore science, we can remind ourselves of these reference points to our faith and redemption and then go on to a better understanding of our relationship with the Godhead because they are true. Because of the Trinity, Pentecost makes sense, because of the Trinity, the Resurrection makes sense, because of the Trinity, the Ascension makes sense, because of the Trinity, creation makes sense, and so on. Because of the Trinity, we can have arelationship with the Father and the Son and the Holy Spirit, all at the same time.
