Abusing Thermodynamics: Introduction

For some reason the laws of thermodynamics get particularly abused by creationists. Undoubtedly this is because most of them do not understand them, but a few do, and they should know better. For them, it looks like deliberate deceit. This post introduces the laws, and subsequent pages on this topic will look at the claims of creationists (and one IDist) who hold at least a doctorate and should understand the subject.

There are four laws and, like a C-style array, they are numbered from zero. The important two are the first and second.

The First Law

The first law says that energy (of which matter is one form) is conserved. That is, for any change, the energy at the end of the process is equal to the energy at the start. That energy may have moved around or been converted into a different form, but the total overall energy is the same. Mathematically:

E(i) = E(f)

... where E(i) is the initial energy, E(f) is the final energy.

The Second Law

The second law says that entropy (which is a measure of how well spread out energy is) must increase. That is, for any change, the entropy at the end of the process is greater than the entropy at the start. Now that entropy may have moved around, but the total overall entropy must increase. Mathematically:

S(i) < S(f)

... where S(i) is the initial energy, S(f) is the final energy.

A Tendency?

It is worth noting than when you look at individual particles neither law holds, and the Second Law is often described as a tendency. However, at the macroscopic scale the laws are universal - and if it is large enough to see, then it is big enough for the laws to apply.

Energy can be created and destroyed in extremely small amounts for a limted amount of time (see here for more on that), as long as that apparent violation of the First Law is below the limit of the Heisenberg Uncertainty Principle (though there is an alternative way of looking at it).


The Second Law arises because of the magic of big numbers. At the scale of atoms and molecules, entropy can go up or down, but it is statistically more likely to go up. At the macroscopic scale (anything big enough to see), a tendency in such a vast number of particles has become a certainty. This is the only exception to the Second Law, and I mention it only for completeness. It is not necessary to invoke any such exceptions to explain evolution.

Open and Closed Systems

People often talk about open and closed systems (and sometimes isolated systems too) with regards to these laws. If you have a system that is perfectly insulated so that matter and energy cannot go in or out of it, then energy must be conserved and entropy must increase.

But this is also true in an open system, as long as you consider the overall energy and the overall entropy, and all natural systems are open, so really the distinction is not worth bothering with.

Configurational Entropy, Conformational Entropy and Information Entropy

There are several different types of entropy out there some related to thermodynamics and some not, and often the same name is used either way. In thermodynamics, configurational entropy and conformational entropy are both part of a molecule's total entropy; configurational entropy is the part relating to the arrangement of its atoms, while conformational entropy is the part relating to how a polymer chain is arranged. Information entropy could be a way of looking at thermodynamic entropy (the more spread out the energy, the less you know about where it is, so in a sense information entropy has increased). It is also a legitimate term in information theory - but that does not mean the Second Law of Thermodynamics applies to it.

All three are abused by creationists by applying them to something they should not.

Entropy: An Extrinsic Property

The amount of entropy in a material depends on its state (temperature and pressure essentially) and how much is present; it is an extrinsic property. It does not depend on how the experimenter chooses to measure it. It does not depend on how it got to that state.


For example, 18 g of water (1 mole) at 25°C has an entropy of 69.9 J/K. It does not matter how the water was created or how it got to that state; its prior history is irrelevant (afterall, the water cannot remember what happened). If it is at 25°C and there are 18 g, then it has an entropy of 69.9 J/K. You can see more examples of entropy values here.

The first important point here is that if your ideosyncatic method of calculating entropy gets a value different to 69.9 J/K for 18 g of water at 25°C, then your method is nonsense (when converted to the same system of units). If it gets different values depending on arbitrary choices in the calculation, then your method is nonsense. Creationists are good at making up new ways to determine entropy, or at least some property that they label entropy, but many of them involve subjective choices in the way the system is examined, and very different results are obtained when it is looked at another way.

The other important point is that thermodynamics does not depend on how it happened. You can determine the overall entropy at the start, you can determine the overall entropy at the end. Has the entropy gone up? If so, the Second Law is being obeyed. How it gets from the start to the end is irrelevant. Creationists have a nasty habit of pretending that the mechanism is relevant. It is not. It may be that a consideration of the mechanism makes a process impossible, but that has nothing to do with the second law of thermodynamics.