This is an expansion on something I posted in a different thread, it was off topic and the thread was promptly hijacked. Right up front I want to make clear that I’m not making any comment here about the merits of evolutionism or creationism. I’m ONLY trying to explain why it’s a poor tactic to use a Second Law argument in an attempt to refute evolution. So please don’t start with how Darwin was this or that, don’t talk about the flood or how Piltdown man was a hoax or polonium halos or anything, it’s simply not relevant. Please confine your comments to the Second Law, and provide a clear mathematically valid reason why I’m wrong if you think I am.
I believe I’m qualified by training and experience to speak as an expert on this topic. I hold a Bachelor of Science Degree in Mechanical Engineering (Cum Laude) from a respected university, I got a 98+ in Thermodynamics (similar grades in physics, calculus and statistics), I have 12 years experience in the automotive industry, and I’ve thought about this a lot.
We’ve all heard the argument that the Second Law says that the disorder of a system increases with time, so evolution can’t be true because it would require a violation of physics. This argument is based on a basic misunderstanding, both of what entropy is, and of what the Second Law says and what it means.
Entropy is a state property of matter that describes the availability of heat to do work. Its value is dependent solely on the temperature and pressure of the substance, and it is expressed in units of Joules per degree Kelvin. At absolute zero, a perfect crystal has an entropy of zero. As temperature rises, so does the entropy of the substance. When the substance changes phase (such as when ice melts) its entropy changes even though its temperature does not.
The Second Law is a mathematical description of the ability of the energy of a system to do work. It states: “In a closed system, entropy increases for irreversible processes and remains constant for reversible processes”. Another way it can be stated is “There can be no machine whose only effect is to cause heat to flow from a cold body to a warm body.” And yet again, “There can be no machine that converts heat energy into an equal amount of work”. In other words, no machine is 100% efficient.
Entropy is related to “order” only insofar as “order” describes the state of the energy in the system. If all of the heat energy is contained in one body and the other body is at absolute zero, then the entropy of the system is at a minimum. When the two bodies are brought into contact and heat flows from one to the other, the entropy of the hot body decreases, while that of the cold body and the system increase. So one can say that entropy is related to how well segregated (ordered) the energy of the system is, but it is not true to then say that entropy is, in general, a measure of order or disorder. The spacial arrangement of the objects in the system, in and of itself, has no bearing on entropy.