This weekend we had a pretty exciting philosophy of physics conference here in the big red R. Sean Carroll was there.  Oh, you don’t know who Sean Carroll is?  Well, he’s famous, he has a blog, and he just wrote a book, which I will read as soon as a friendly man in a brown uniform drops it at my door.   [Warning: this post may be long]

Carroll’s project is very similar to David Albert’s in Time and Chance: he’s trying to locate the arrow of time in thermodynamics, claiming that t1 is in the future of t­0 just in case t1 has higher entropy than t0 and there is a steady entropy increase between the two.  Entropy, roughly, measures chaos—a box in which particles are all spread out has more entropy than one where particles are all bunched up in a corner, my office has more entropy than Meghan’s, and  Jackson Pollock’s paintings have more entropy than Piet Mondrian’s.