Sunday, January 16, 2005

Trinity and the Triple Point of Water

Dear Mr. Vallicella,

I have been following your arguments on the topic of the Trinity with great interest and enjoyment. In your latest post you say "that a quantity of H2O can be in the three states only successively not simultaneously...". Water can in fact be in three states simultaneously: such a state is referred to as its triple point.

BV: That's fascinating. You may have nailed me on a physics mistake. Ouch! But I have a couple of questions. Looking at some pressure-temperature diagrams, like this one, it appears that I am right in my claim for H2O at sea level. Is that right? Secondly, and more importantly, thermodynamics, and physics generally, make use of all sorts of idealizations. The ideal gas, for example, the gas for which the gas laws hold, is an idealization. Center of mass and center of gravity are idealizations for calculational purposes: no one thinks that the mass of a projectile is concentrated in one mathematical point inside it. So my second question is this: is there an actual empirically detectable phenomenon in nature that is H2O in all three states at once? Or is this just a mathematical point of intersection on a phase diagram that does not correspond to anything empirically detectable?

I am not being as clear as I ought to be because I am not sufficiently en rapport with the physics. But might it not be like this? You've got a piece of ice. If you heat it up enough, at the triple point, some of it becomes liquid and some of it become gaseous. But no collection of H2O molecules are in all three states at once.

I believe that the water analogy as used has been deemed incorrect for the very reasons you say; God is not modal. However, water at its triple point may in fact best describe the Trinity as it is maintained by believers.

BV: This is indeed fascinating, and you may well be right. But I need to be convinced that the triple point of water -- or indeed the triple point of any chemical substance -- is an empirically detectable phenomenon in nature and not a mere point of intersection on a phase diagram.

All the best to you and keep up the blogging.

Yours Sincerely,

Pat Hannagan