Reddit mentions of Time and Chance

Interesting to note: since thermodynamics is Newtonian, and Newtonian physics is time-reversable, entropy also increases going backwards in time. To get around that, you have to insert prior information into the problem by assuming a low-entropy state in the past.

In that sense, it's not entropy maximization that breaks the symmetry, but the prior information.

Discussed in more detail in this book.

I'm not exactly sure what you mean by saying that you want to focus on astronomy; I'm not aware of much in the way of the philosophy of astronomy. There's been some movement toward establishing the philosophy of cosmology as a distinct subfield, but it's still a relatively new thing, and there's not a lot out there. Your best bet, probably, is to focus more on the philosophy of space and time more broadly, so that's the kind of stuff I'm going to suggest. I'm not sure what your starting level is, but here are some things that might be worth your time:

• Hans Reichenbach's The Philosophy of Space and Time and The Direction of Time
  
  
• Tim Maudlin's The Metaphysics Within Physics and Quantum Non-Locality and Relativity
  
  
• Gordon McCabe's "The Structure and Interpretation of Cosmology"
  
  
• Josh Knobe's "The Philosophical Implications of Inflationary Cosmology"
  
  
• David Albert's Time and Chance and After Physics
  
  
• Huw Price's Time's Arrow and Archimedes' Point
  
  
• Larry Sklar's Space, Time, and Spacetime
  
  There's a lot more out there, but a close reading of even all this is probably beyond the scope of single semester. If you can say a little bit more about what exactly you're interested in, I might be able to narrow things down a little bit.

I took a Philosophy of Physics course as an undergraduate and we focused on thermodynamics and the arrow of time. I'd recommend the two books we read:

Physics and Chance, by Sklar:
It looks at the philosophical issues associated with the statistical mechanics approach to thermodynamics.
http://www.amazon.com/Physics-Chance-Philosophical-Foundations-Statistical/dp/0521558816

Time and Chance, by Albert:
A little more accessible than Sklar.
http://www.amazon.com/Time-Chance-David-Z-Albert/dp/0674011325

I discuss that a bi more in the new book, and David Albert looks at it carefully in his book:

http://www.amazon.com/Time-Chance-David-Z-Albert/dp/0674011325/

The main point is that we can only successfully correlate conditions in the current universe (such as "I remember liking that show") to what conditions actually were ("I was watching that show, liking it") because entropy used to be lower. Otherwise, the most likely explanation would be "the impression that I liked the show just randomly fluctuated into existence."

Not really. For the cup to break to subatomic level, you'd need to have enough energy from the fall of the cup to break the cup to that level and you just haven't. This motion is forbidden by the laws of mechanics alone.

Second, I'm talking about microstates. The macrostate is the cup broken in that particular arrangement. The microstates are the different atomic configurations that at the macrolevel look like that exact same broken cup and not another broken cup. We're not even looking at broken something elses.

Look, this was my best attempt to an ELI5 explanation of a question that is not even an ELI5 question. No 5-year old kid will ever ask what a Boltzmann brain is unless he has read about thermodynamics and statistical mechanics. And at that point, it's better to give the full and correct mathematical explanation rather than an approximate one. So, if you're not satisfied with the reply, I advise you to read up on the subject.

I advise "Time and Chance" by David Z. Albert as an excellent semi-technical read on the subject. But you'll appreciate it more if you have a background in thermodynamics and statistical mechanics.