Tuesday, October 31, 2006

Kingdom Thermodynamics 1: Introduction

I should start this series of posts by suggesting that perhaps it does not really belong at Speaker of Truth. For I cannot presume to call what I intend to write here, at least after this introduction, "truth". I hope that it is an exploration in the direction of truth, but some might prefer to write it off as "speculation". On the one hand, these are preliminary thoughts on this subject, and are liable to be refined at any time. On the other hand, although this is, I think, the first time I have gone public on this, I have already been thinking it over on and off for about 30 years. Yes, really: I remember doing some research on this when I was a student in Cambridge, it must have been 1976 or 1977, in the library of the Cavendish Laboratory.

As a student of physics at that time, and as a young Christian, I was fascinated by time, and I still am. I learned that almost all of the fundamental laws of physics are time-invariant, that is to say, they work exactly the same when time is reversed. If you watch a film which only shows things operating according to these laws, you cannot tell whether it is being played forwards or backwards. This applies, approximately, to such things as swinging pendulums and heavy objects travelling through the air; it also applies, perfectly, to all process on the atomic scale (technically, if charge and parity are also reversed).

There is just one fundamental law of physics which is not time-invariant: the Second Law of Thermodynamics. This law in its most basic form states that the entropy of a system always increases, which means that the system gradually become more disordered. This may explain the state of my desk! It also explains why heat always flows from hotter to colder bodies, and why moving objects, unless in a vacuum, slow down and stop unless a force is applied to keep them moving. These are all processes which are not time-invariant; if you see a film which shows systems spontaneously becoming more ordered, heat flowing from colder bodies to hotter, or moving objects speeding up without a force, you quickly realise that it is being played backwards.

On the face of it this law, that systems will always become more disordered and will tend towards a state of uniform temperature and only random motion, might seem to be a rather negative and useless one. However, biological systems are able to make use of this law to produce effects which seem to contradict it - but do not really do so, for an organism can decrease entropy in one place only by increasing it even more in other places, typically by converting low entropy food into high entropy waste products. Similarly, human ingenuity has contrived various kinds of engines, which are basically methods of creating ordered motion by converting low entropy fuel into high entropy exhaust gases; thus the modern human world can continue its activities by generating huge amounts of waste entropy which (to grossly oversimplify some very complex processes and issues) causes global warming.

There is something rather special about the Second Law of Thermodynamics which goes beyond its breaking of time invariance. The early 20th century physicist Arthur Eddington wrote:
The second law of thermodynamics holds, I think, the supreme position among the laws of Nature. If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equations - then so much the worse for Maxwell's equations. If it is found to be contradicted by observation, well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation.
What made Eddington so sure of his ground on this one? I am sure that it was not just that the Law fitted so precisely with observation. Eddington's own greatest claim to fame is that he was the first to confirm Einstein's General Theory of Relativity by detecting a small deviation from Newton's laws. But he did not seem to allow that there might be even such tiny deviations from the Second Law of Thermodynamics. The reason for this seems to be that, in addition to the experimental evidence, there is a fundamental philosophical and logical basis to the Second Law. It was this basis that I was researching at the Cavendish Laboratory, where Eddington had studied before me.

But my interest in this issue was sparked all those years ago not so much by the physics involved as by what is taught in the Bible. I read (at that time not in this version) and thought about the following:

19 The creation waits in eager expectation for the children of God to be revealed. 20 For the creation was subjected to frustration, not by its own choice, but by the will of the one who subjected it, in hope 21 that the creation itself will be liberated from its bondage to decay and brought into the freedom and glory of the children of God.

22 We know that the whole creation has been groaning as in the pains of childbirth right up to the present time. 23 Not only so, but we ourselves, who have the firstfruits of the Spirit, groan inwardly as we wait eagerly for our adoption, the redemption of our bodies.

(Romans 8:19-23, TNIV)
These verses fascinated me. The Apostle Paul wrote that "the creation was subjected to frustration... [in] bondage to decay", and he was writing 1800 years before physicists formulated the same principles as the Second Law of Thermodynamics. But, whereas for physicists like Eddington the Second Law is absolute and immutable, Paul wrote that this "bondage to decay" is ordained by God as something temporary, from which it can eagerly expect liberation.

But how could I, as a physicist at the time and later as a student of theology, bring together these two opposing viewpoints on the same phenomenon? What is the philosophical basis of the Second Law of Thermodynamics, and how does this compare with Christian teaching? Could the differences here be linked to the "problem" of miracles, events which seemed to break the laws of physics? And how does it all relate to the coming of the Kingdom of God and our hope of experiencing "the freedom and glory of the children of God"? I hope to deal with these matters in future posts. But I am posting this introduction without having written any more, so don't expect the rest of the series very quickly!

Update: see part 2: Beyond Causality; part 3: The Boundaries; part 4: The Crunch.

1 Comments:

At Wednesday, November 01, 2006 12:45:00 am, Blogger codepoke said...

Excellent question, Peter! I'll be watching this one. :-)

Physics -> Good!

 

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