"The Ties That Bind," the third episode of the season, was dark, dark, dark indeed. While the title implies that the episode is about the things that hold us together, what we got was a look at what happens when those ties unravel.
The main themes this week are alienation and disassociation, and they play out on every possible level, from the alienation we sometimes feel from ourselves at the most personal level to the alienation we can feel from the institutions that govern us and represent the societal values we hold dear. Apart from the personal stories we look forward to following every week, BSG is compelling drama in part because it offers us space opera parallels to contemporary issues. Like most good science fiction, it's never about our future as much as it's about our present, and it's no accident that a lot of the issues the Colonists worry about sound as if they're ripped right from the headlines of our morning newspaper.
On a personal level, we witness the alienation of Cally Tyrol, who's life is unraveling in a very big way. Left alone much of the time by a husband who is distracted (and alienated) by his newfound secret identity, she's trapped in their quarters with a frequently fussy baby and suffering from depression. She's so cut off from the things that sustain her that by the time she discovers the Chief's secret Cylon nature, her best option seems to be taking her own life and that of her baby.
Laura Roslin is alienated from herself too, in particular her body. In sick bay, she settles in for another nausea-inducing round of chemotherapy. In spite of the fact that Adama comes in to read to her while she waits out the chemo, it's clear to us later on that these two are now alienated from each other as a result of Adama's unilateral decision to send Kara Thrace off on a search for Earth. And on board the Demetrius, Kara pores over her star charts and maps, trying to plot her way to her destination, but she keeps herself at a distance from her crew — and they have little confidence in their mission as a result. When she tells Anders that feels disconnected from herself, as if she's on the outside looking in, we wonder whether to take it literally or figuratively given recent events surrounding her re-appearance (and judging from the expression on his face as she talks, we know that he's wondering the same thing).