So last time I was discussing the second law and I explained it almost entirely in terms of “energetic” entropy, the dissipation of potential energy, which the earth’s biosphere produces by taking concentrated solar radiation (UV-visible light) and breaking it up into dilute, thermal radiation (heat). I used this example as my primary focus for several reasons. First, as I mentioned previously, the net conversion of light to heat is a precise measure of the overall entropy production of the earth. It is also usually NOT what people think about when they hear casual discussions of entropy. They think about “spontaneously increasing disorder,” which meshes nicely with our anthropocentric intuitions about the futility of our efforts in the face of time and the central moral creed of the 20th century: “The universe doesn’t give a damn about you.” Well the universe grew you, but whatever, it’s fun to feel heroic and unique using your powers of reason to bravely face the indifferent void.
At any rate while I’m going to continue to insist that entropy has absolutely nothing to do with disorder, mostly because I don’t know what disorder is even supposed to mean in a thermodynamic context, there is a perfectly valid concept known as “configurational entropy.” Configurational entropy refers to the range of energetically allowable material configurations a system possesses. So if the theme last week can be compressed as "Energy randomization," this week the theme is the operation of the second law on material possibility, "Matter randomization." Matter randomization is driven by the production of configurational entropy and it is also at the heart of most of the confused notions about entropy and disorder. Dispelling these confusions will hopefully also provide a clue as to why the second law promoted, rather than hindered, the increase in molecular variety that was critical to the emergence of life.