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Responding to Granville Sewell, Yale Neurologist Steven Novella on Evolution and the Second Law of Thermodynamics

220px-Steven_Novella_2008.jpgSteven Novella, clinical neurologist at Yale University School of Medicine, has written a post at his blog Neurologica in reply to Granville Sewell, a scientist and mathematician well know to readers of ENV.

For years Sewell has pointed out that, on the basis of the Second Law of Thermodynamics, evolution by natural selection is an inadequate explanation for the extraordinary specified complexity of living things. Sewell is highly qualified in this debate: he is a professor of mathematics at the University of Texas and has a background in mechanical engineering. 

Sewell has a new paper in the journal BIO-Complexity. This is the abstract:

It is widely argued that the spectacular local decreases in entropy that occurred on Earth as a result of the origin and evolution of life and the development of human intelligence are not inconsistent with the second law of thermodynamics, because the Earth is an open system and entropy can decrease in an open system, provided the decrease is compensated by entropy increases outside the system. I refer to this as the compensation argument, and I argue that it is without logical merit, amounting to little more than an attempt to avoid the extraordinary probabilistic difficulties posed by the assertion that life has originated and evolved by spontaneous processes. To claim that what has happened on Earth does not violate the fundamental natural principle behind the second law, one must instead make a more direct and difficult argument.

Please read Sewell's whole paper. It's a superb pr�cis of the argument that, based on considerations of entropy, life calls for an explanation other than undirected natural selection.  

Novella begins his critique of Sewell's argument with the usual Darwinist ad hominem:

Creationists will just not let go of an argument, no matter how many times it is pointed out to them that their argument is unsound. They simply find new twists of logic and distortions of science to resurrect their precious argument, clinging to it more tightly than Gollum held onto his ring.

Novella is having none of these entropy arguments:

Such statements may be persuasive to the masses, but not to scientists and intellectuals... every scientist familiar with this creationist argument knows why it is fatally flawed. The earth is not a closed system, it receives energy from the sun. The total entropy of the earth-sun system is spontaneously increasing, and the local decrease in entropy of the earth’s biosphere therefore does not violate the second law.

Novella's effort to enlighten the benighted masses falls short. Here's why.

Sewell quotes Andy McIntosh, professor of thermodynamics and combustion theory at Leeds University:

these [arguments entail] the same assumption -- viz. that all one needs is sufficient energy flow into a [non-isolated] system and this will be the means of increasing the probability of life developing in complexity and new machinery evolving. But as stated earlier this begs the question of how a local system can possibly reduce the entropy without existing machinery to do this.

Sewell is right. Merely asserting that "the sun did it" is not adequate to explain a local reduction in entropy. If it were, one could explain the existence of anything-- a building, a computer, a jet plane -- just by asserting "the sun did it," without invoking any other mechanism. 

So the question that Novella fails to address is this: how can evolution be a sufficient mechanism to explain the dramatic reduction in entropy in living things? Bizarrely, Novella asserts:

Life can use energy to decrease entropy -- that one simple statement obliterates Sewell’s entire paper.

Which obviously begs the question. We are trying to explain how it is that life can reduce entropy. Novella's assertion that life can use energy to do so merely assumes the thing -- life -- that we are trying to explain. 

Let's look at the question about entropy and life with a bit more rigor.

The remarkable decrease in entropy associated with living things is in need of explanation. Entropy can locally decrease in a system, but we are right to ask for an explanation. 

Darwinists offer evolution as that explanation. But evolution is a vague term -- certainly Darwinists don't mean that the fact that populations of organisms change with time is an explanation for life. 

The Darwinist explanation for complex low-entropy life is natural selection. Natural selection is differential reproductive success. 

How could differential reproductive success explain a reduction in entropy? First, it should be noted that differential reproductive success doesn't create low entropy. It only preserves low entropy organisms that, as it happens, are more reproductively successful than their neighbors.  

So how can low entropy states in living things arise in the first place, in order to be available for preservation by natural selection?

There would seem to be two ways. The first is law-like: matter can aggregate in low entropy ways in accordance with natural laws. Gravity draws clumps of interstellar rock into planets and solar systems. Quantum mechanics orders atoms and crystals. 

But natural selection acting on random variation is surely not like this. Natural selection isn't law-like at all. Adaptations are dependent on the ecological niches in which critters happen to find themselves, not on laws. There is no "law" of natural selection that ascribes reproductive success to wings or gills. If you're living in trees, wings may help. If you're living in the ocean, wings get in the way. If you live in air, gills won't do much for you. Gills are a big help if you live in water. 

Natural selection depends entirely on natural history, the adaptation of organisms to environments in which they happen to find themselves -- one damn thing after another. Natural history is not law-like. 

Natural selection -- adaptation to an ecological niche -- does not reduce entropy in living things like the laws of quantum mechanics reduce entropy in crystals. 

The second way that natural selection could reduce entropy is if it were intentional, in the philosophical sense that it could be like a mental construct imposed on nature. If natural selection could plan organisms, like an architect, it could locally reduce entropy. 

But of course natural selection is a blind watchmaker, and plans nothing. That was Darwin's radical claim -- that he had discovered a mechanism by which complex life could evolve without intelligent agency being involved. 

Only two mechanisms are known to be capable of reducing entropy locally: physical laws and mindfulness. Natural selection is neither law-like nor mindful.

As Sewell points out, a critical scientific look at Darwinist theory fails to support Darwinist claims. The earth and sun together form a closed thermodynamic system, more or less. Entropy can decrease locally in a closed system, of course, as long as total entropy increases. But local decrease in entropy requires a mechanism sufficient to explain it.  Natural selection can't explain local low entropy -- it is neither law-like nor mindful. 

Teleology and intelligent design, on the other hand, are law-like and mindful. And that would seem to make all the difference.

Image credit: Steven Novella/Wikipedia.