Thermodynamics post on my blog. Not directly related to rationality, but you might find it interesting if you liked Engines of Cognition.
Summary: molar entropy is normally expressed as Joules per Kelvin per mole, but can also be expressed, more intuitively, as bits per molecule, which shows the relationship between a molecule's properties and how much information it contains. (Contains references to two books on the topic.)
We've had these for a year, I'm sure we all know what to do by now.
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