Colloquium Lecture: Entropy and Complexity--Heather Demarest, University of Colorado Boulder

Join us for a lecture on "Entropy and Complexity" by Heather Demarest, an associate professor in the Department of Philosophy at the University of California Boulder. Abstract: The second law of thermodynamics states that entropy (almost) always increases over time.

However, different systems do this in very different ways. In some systems, like boxes of gas, entropy increases smoothly and uniformly. In other systems, such as refrigerators, crystals, trees, zebras, and human brains, entropy decreases in parts of the system, while increasing in other parts.

A zebra (together with its environment) does not violate the second law, but there is an important sense in which the zebra resists (or perhaps more accurately, exploits) the second law. The zebra maintains or reduces its entropy by shunting its extra entropy into its environment.

This is possible because the zebra consumes highly ordered, low-entropy energy (grass) and excretes higher entropy waste (heat and manure). In this talk, I defend a metaphysical account of this difference in terms of multiple realizability--the more microphysical realizers a kind has, the less it is able to resist the second law.

I make this notion precise with functional information of macrostates in the phase space of statistical mechanics.