I use cosmology examples to illustrate that the second law of thermodynamics
is not old and tired, but alive and kicking, continuing to stimulate
interesting research on really big puzzles. The question "Why is the entropy so
low?" (despite the second law) suggests that our observable universe is merely
a small and rather uniform patch in a vastly larger space stretched out by
cosmological inflation. The question "Why is the entropy so high" (compared to
the complexity required to describe many candidate "theories of everything")
independently suggests that physical reality is much larger than the part we
can observe.Comment: Transcript of talk at the MIT Keenan Symposium; video available at
http://mitworld.mit.edu/video/513, including slides and animation
