I am an evangelical Christian. I believe the Bible to be entirely trustworthy in conveying God's messages
The Second Law and Creation
Now we address the context in which the 2nd law arises in creation arguments. The usual argument goes something like this: "The 2nd law says everything tends toward increasing entropy (randomness and disorder). But the evolution of life involves the development of great complexity and order. Therefore, evolution is impossible by the 2nd law of thermodynamics." While it sounds simple, there are major flaws in this argument that render it worthless.
The Earth is Not an Isolated System
It is only in isolated systems that entropy must increase. Systems that can exchange energy with their surroundings have no such restriction. For example, water can freeze into ice (becoming more ordered and decreasing its entropy) by giving up heat to its surroundings (this increases the entropy of the surroundings, of course). In the case of the Earth, the Sun is a major source of energy, and the Earth also radiates energy into space. One consequence of thermodynamics is that, when energy comes from a "hot" source (like the Sun) and is output to a "cold" reservoir (like space), it can be used to do work, which means that "complexity" or "order" can be produced. The main point is that, for a non-isolated system, an increase in "complexity" (to the extent one can connect that concept with the thermodynamic entropy, which is far from straightforward for living creatures) does not necessarily indicate a violation of the 2nd law. A good example is the development of a human fetus into an adult; this is the production of a more thermodynamically complex system but involves no violation of the laws of thermodynamics.
It is worth mentioning here that the usual reply to creationists that "the second law doesn't apply to non-isolated systems" is not quite correct. The second law always applies; in fact, it was originally developed for non-isolated systems (the working fluid of a heat engine). The key point is that it is only in isolated systems that the second law takes the simplified "entropy must increase" form. For non-isolated systems, the second law still applies as a statement about heat flows and temperatures, just not in the form used in creationist arguments.
An Internal Inconsistency
Some creationists assert that advanced (especially human) life represents a decrease in entropy which violates the 2nd law, and they therefore invoke intervention by God, who is outside the laws of thermodynamics. They also, however, generally assert that this particular "intervention" stopped with the creation of man, and that (with the exception of the occasional miracle) God has allowed things to develop in accordance with the laws of thermodynamics and other physical laws since then.
These two assertions are, however, mutually inconsistent. The reason is that the thermodynamic entropy is strictly an additive quantity. If the 2nd law has not been violated as the number of humans grew from two to 6 billion, it is ridiculous to assert that it was violated in the comparatively minuscule change from zero to two. If we say that the first two humans represented a violation of the 2nd law, the logical conclusion would be that God must be continually intervening in violation of the 2nd law in order to increase the number of humans on Earth. While God is certainly capable of this, there is no evidence to suggest that such violations are happening as complex life forms like humans reproduce and increase in number. [NOTE: All this is not to say that God's creation of human life was not miraculous. My only point is that the specific assertion that the existence of human life in and of itself violates the 2nd law is unfounded.]
plus the catholic church even believes in evolution
