@KenoFischer already did a great job explaining the paragraph, but the audience is professional philosophers, philosophy graduate students, and some philosophy undergrads. I parsed this SEP entry for one of my undergraduate courses (Philosophy of Space & Time).

If you're interested in the topic, I suggest reading Time and Space by Barry Dainton[1]. It was suggested reading for our class and primed me for anything from time time travel to general relativity.

[1] http://www.amazon.com/Time-Space-Barry-Francis-Dainton/dp/07...