Thermodynamics is the study of the transfer of heat energy. There are three main laws of thermodynamics, the second being frequently brought into arguments against evolution.
In any process, the total energy of the universe remains constant.
There is no process that, operating in a cycle, produces no other effect than the subtraction of a positive amount of heat from a reservoir and the production of an equal amount of work.
As temperature approaches absolute zero, the entropy of a system approaches a constant.
The laws of thermodynamics have also been described in a tongue-in-cheek way as:
- You can't win.
- You can't break even.
- And you can't get out of the game.
Creationists claim that evolution is impossible because the second law of thermodynamics does not allow an unguided increase in complexity.
The most common definition of the second law is: "The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium." The second law of thermodynamics uses the word entropy, which is what causes the confusion (Or allows the lies, depending on how you look at it.) The meaning of the word entropy that is used in the second law is: "For a closed thermodynamic system, a quantitative measure of the amount of thermal energy not available to do work." Using that correct definition the second law of thermodynamics obviously has nothing whatsoever to do with evolution. It never did, it's just about thermal energy. (As should be evident by its very name.)
But the definition that the apologists use is: "A measure of the disorder or randomness in a closed system." And using that definition, the second law of thermodynamics would mean: The random disorderliness of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium. However, this is not only an incorrect use of the second law. It is also untrue, some closed systems will tend to fall into disorder, while some will become more orderly. Examples: Disorderly dust clouds in space eventualy gravitate towards a central/denser point, forming a star.
If we presume that humanity is orderly, and that the apologists definition of entropy is valid, we should observe the continuous destruction of humanity - human populations should dwindle, human technology should decline. That this is not occurring is not evidence that the definition is incorrect - it would mean that the Earth is not a closed system. Evolution is compatible even with the apologists definition - the earth itself is not a closed system. In a universe consisting solely of the earth and the sun, biological evolution is still possible - the total "randomness" will increase consistently as the sun releases energy, but on earth, that energy converts to temporary order.
So in summary, the second law of thermodynamics has nothing to do with evolution, the beginnings of life, star formation, or anything at all other than the movement and/or effects of energy.