Thermodynamics and Anti-Entropic Mechanisms (my most techy title ever)

Question from Simon:
I was debating with a Christian friend about evolution and the genesis of life and I have to admit that he stumped me in regards to thermodynamics. He agrees that you can have a localised reduction in entropy as long as the overall system entropy increases (which is where most of the pro-evolution arguments seem to end) however he argues that to do so, you require some form of mechanism to drive the decrease as spontaneous localised decreases in entropy do not occur either in open or closed systems. Can you offer an explanation which supports or refutes this?

Answer by SmartLX:
Spontaneous localised decreases in entropy (i.e. increases in order) do not require the kind of mechanism you and the creationist are thinking of, only a bit of physical force.
– If you have a jar filled partially with rocks and sand and you shake it randomly for a while, the smaller particles will tend to make their way towards the bottom of the jar while the big ones stay on top, ordering the collection solely through gravity and friction.
– Chemists regularly use a centrifuge to separate heavier elements of a mixture or compound from lighter parts through centripetal/centrifugal force alone.
– Oil and water mixed together will separate vertically to some extent, even if you don’t agitate them. Gravity again, plus surface tension and possibly other parts of fluid dynamics I don’t fully understand.
– A group of small magnets dropped randomly in a bucket will snap together into a structure. Depending on their shape, many of them may join in a very straight line. Iron filings will arrange themselves into beautiful patterns around an electromagnet, and ferrofluid has to be seen to be believed.

There’s a creationist idea that all new order (physical, chemical, linguistic, etc.) requires a mind to create it. You’re up against a more flexible idea that new all order requires a mechanism, whether or not a mind is ultimately behind that, but there’s no more evidence for this idea than for the other. The inorganic forces of this planet (wind, tides, tectonic shift, orbital spin) were what the initial chemicals of life needed in order to come together and form a useful configuration. Once life existed it was capable of exerting its own forces, for good or ill, and evolution took hold through natural selection. We don’t know the details, but there is no discernible problem with the principle, no matter how much creationists would like there to be.