USS Clueless -- Evolution and Thermodynamics

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Evolution and Thermodynamics

One of the more stupid objections to the theory of Evolution cited by the creationists is that it violates the Second Law of Thermodynamics. This is utter nonsense and proves that those making this claim understand thermodynamics even less than they understand evolution.

The laws of thermodynamics are among the most important scientific discoveries of all time. There are three.

The First Law is the law of conservation of energy. Energy cannot be created or destroyed; it is merely transformed from one form to another with neither gain nor loss. This was modified by the Special Theory of Relativity which, among many other important results, showed that matter and energy were the same thing. But the First Law still applies, because mass/energy is still a conserved quantity, with the conversion rate each way being according to a constant rule. If mass is converted to energy and then back to mass, there is neither gain nor loss.

The Third Law defines what "zero entropy" is, by defining a case of perfect order. (It's a perfectly regular crystal at zero degrees Kelvin.)

It's the Second Law that the creationists are so thrilled about. It demonstrates the existence of entropy, and it refers to the fact that in every transformation of energy, some of the energy becomes useless. The Second Law defines the theoretical minimum amount of useful energy which is lost in the transaction. This energy isn't destroyed (which would violate the First Law) but it can't be used to do what a scientist refers to as "work". This discovery had profound effects on nearly all kinds of engineering.

This is a critically important law, because it is the only scientific principle known which is not symmetrical with respect to time. Indeed, some people think that time may well be entropy, though there is no proof of that yet.

Order is energy. (That's what the Third Law says.) Disorder is a lower energy state than order (or rather, a state where more of the energy is useless). Information is order, and thus stored information is inherently a high-energy state. So the creationists say "The Second Law says that disorder will increase -- so how could evolution create more complex organisms without violating it?" Well, it's because that's not what the Second Law actually says.

The Second Law applies to closed systems and says that the average disorder in the entire closed system will increase with time. (It also applies to individual energy transactions, and to a lot of other things, but within this context it is its systemic aspect which is important.)

This does not apply to open systems. A closed system is one which has no energy transactions outside its borders. An open system has the ability to trade energy in various forms with other systems. A closed system is made up of component open systems, and the Second Law doesn't apply to an open system.

It's possible for an open system to import order and export disorder, locally increasing order. What the Second Law says is that in such a transaction more disorder than order will be created. It does not, however, forbid the creation of pockets of order. What happens is that disorder in the entire closed system will increase even though individual open systems within it might become more ordered.

So the creationist application of the Second Law is wrong because life is an open system, not a closed system.

In any case, if the creationist interpretation of the Second Law was correct, a lot more things than evolution would be impossible. For instance, it would be impossible to breed. You start with two humans and end up with three. Looks like an increase in order to me -- obviously it can't happen. It would also be impossible for a child to grow: five years ago she weighed 20 kilos and now she weighs 35 kilos, which means we've created an additional 15 kilos of ordered mass.

For that matter, it would mean that a refrigerator would be impossible, since "cold" is a form of order.

Not all heat is disorder, but all disorder is ultimately heat. (The Second Law defines precisely how much of the heat in a warm pocket is useless.) What a refrigerator does is to create a pocket of cold by making something nearby more hot (moving the heat from one place to another). This creates a temperature differential, which is a form of order. But doing this involves expenditure of energy which itself becomes heat, so more heat than cold is produced. If the refrigerator were turned off and the heat permitted to flow back into the cold zone and "fill in the hole" by destroying the differential, the resulting system overall would be warmer than before, and more of the total energy in the closed system would be useless.

Equally, maintenance of the order of life requires substantial expenditure of energy; we take it in as food and expel it as heat. This doesn't violate the Second Law because we are not closed systems -- and evolution doesn't either. Evolution creates order but the overall system becomes more disordered on average with time. The earth itself isn't a closed system: order is imported as sunlight and exported as radiated heat. The heat enters the background of the universe and the total disorder of the universe increases. As long as the sun shines and the celestial background is cold, life on earth can still flourish. (Unless we pollute ourselves to death.)

The system is definitely running down. The universe may last forever (that hasn't been determined yet) but it will only exist as we know it for perhaps 50-100 billion more years, at which point there will be few hot spots left to act as sources of order for life to exploit. Then the universe's disorder will overwhelm order and life as we know it will become extremely difficult and rare.

Fortunately, none of us will live that long.

This is a particularly egregious example of the nonsense that creationists spout, but it turns out on close analysis that every one of their objections to evolution (and geology, and nuclear science, and astronomy, and a host of other scientific principles) are equally misguided. They sound plausible to someone who doesn't know about the science involved. They are propaganda points, no more. They don't persuade scientists and are not intended to; they're intended to persuade politicians and voters.

Creationism is and always has been politics and religion. It isn't science, and it won't ever be science for a simple reason: it's false.

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