Tuesday, October 23, 2007

The Second Law of Thermodynamics

Creationists often point out that Evolution, if it were true, would violate the Second Law of Thermodynamics (aka The Law of Entropy). This well-established scientific principle basically states that organized systems (living cells, the universe, new cars, sculptures, etc) have a tendency to degrade into a less-organized condition rather than growing into a more organized condition or remaining at the status quo.

For example, new cars eventually break down and become rust-buckets. Living cells develop mutations and become less capable of survival and/or successful reproduction. Sculptures erode away as bird poo and rain water and freeze/thaw cycles eat away at the material. Stars blow up and galaxies spin apart.

Evolutionists are quick to counter that the Second Law only applies to closed systems, and the Earth is an open system, receiving plenty of energy from the Sun to drive the process of Evolution into higher and higher levels of complexity and order.

However, the mere addition of energy will not allow a system to overcome the Second Law.

In order to overcome the tendency toward entropy, toward decay, you need three things:

1) Energy,

2) A machine/mechanism to convert that energy into useful work, and

3) A program to control that machine/mechanism.

As an example, think of a lawn that needs mowing. It is currently in a state of disorder, and we want to convert it into a state of higher order, trimmed neat and level.

If we put this lawn in a big box in order to make it a closed system by preventing energy from reaching the lawn, the Second Law of Thermodynamics does indeed reign within this closed system: the lawn rapidly declines into the disordered state of dead dirt.

However, if we take away the big box, thereby making the lawn an open system, able to receive energy in the form of wind and rain and sunshine, entropy still increases in the lawn: we don't wind up with a lawn trimmed neat and level, but with a field of overgrowth.

So simply adding energy, requirement number one, does not increase the order of a system. It increases the disorder of that system.

So let's add requirement number two, a machine to convert energy into useful work. Let's put a lawn mower out on the lawn.

Are things more ordered now?

Nope. The sunshine and rain is an energy form that the mower can not use. We either need a different form of energy, or a different mower that can use solar and/or rain power. So we learn that not just any energy and any machine will do; they must be matched together.

Our lawn mower needs energy in the form of gasoline. So let's pour a gallon of gas all over the mower.

Has the order of the lawn increased?

Nope. Oh, right; gasoline is just a form of stored energy. In order to release that energy we need a source of ignition.

So we drop a match on the gasoline-doused mower.

Increased order?


The two requirements of energy and a machine to convert energy into useful work are not sufficient to overcome the Second Law of Thermodynamics.

So we add the third requirement: a program to control the machinery.

In the case of our lawn mower, part of this control program is built into the design of the mower. Part of that control program requires that the gasoline go into the gasoline tank rather than being poured all over the mower. (But that's not sufficient either; try dropping your match into the tank. Increased order? Nope.) More of that control program is inherent in the length of the piston rod, and the size and shape of the combustion chamber, and in the timing of the spark, etc.

Now we have energy (gasoline) being converted into useful work (the spinning of the mower's blade).

But even that amount of control program is insufficient to trim the lawn. We need even more of a control program acting on the machine itself, not just one inherent in the machine. In our case, we can use a control program in the form of a person pushing/steering the mower, or of a computer control program in the case of a "smart mower".

Now, finally, we have an increase in order within the lawn.

The only way we've overcome the Second Law of Thermodynamics, the Law of Entropy (the tendency toward disorder), is to fulfill the three requirements needed: an input of energy, a mechanism to convert that energy into useful work, and a program to control that mechanism.

The idea that the Second Law of Thermodynamics does not apply to open systems is simply wrong. An open system is only one requirement of three needed to overcome the Second Law.

No comments: