KILLING YOU NICELY
The single most universal fear any human being has is of death. After all, why would we spend so many hours and so many pages figuring out what happens after we die, metaphysically speaking, if we weren't at least a tiny bit afraid of death? In this episode of Doctor Who, the Weeping Angels have devised the perfect method of murder -- as soon as they touch you, you're zapped to another point in time, usually in the past, where you'll be forced to live out your life isolated from the people and places you're familiar with. Two people Sally Sparrow interacts with in the episode die by this method: Kathy Nightingale, her best friend, and Billy Shipton, the police officer who flirts with her when she goes to the police about the house at Wester Drumlins -- the residence of the Weeping Angels.
There are two strange things about these two characters and the way they react to what happens to them. First, and most interestingly, neither of them feels remorse or despair for being transported to different times. Kathy admits, in her letter to Sally delivered via grandson, that time-traveling is "a strange way to start a new life," but "a new life is exactly what she always wanted." (Of course, she maintains her youthful spirit -- "told him you were eighteen, you lying cow!") Billy Shipton has a similar experience -- he falls in love with another woman named Sally after he gets transported to 1969; he is also instrumental in planting the Doctor's DVD Easter eggs. Indeed, Billy's perspective on time changes -- when asked by Sally why he clocked out of work early, he replies, "Because life is short and you are hot." Later, when Sally meets the elderly Billy Shipton, he says wistfully, "Life is long and you are hot." LOST fans will note the comparison to "The Constant" -- Sally Sparrow is the constant for people in this episode.
The second strange thing about Billy and Kathy is the exact circumstances of their disappearances in Sally's time. Both of them are caught up in other peoples' lives when the Angels take them -- in particular, they're caught up in Sally Sparrow. When Kathy is taken, she's in the Wester Drumlins house, eavesdropping on Sally's conversation with her yet-to-be-conceived grandson (I know, I know -- wibbly-wobbly, timey-wimey stuff). Billy, meanwhile, is flirting with Sally, and only when he looks back over at the TARDIS does he even notice the Angels creeping up on it. And then, in the blink of an eye, their lives are gone. Creepy.
Of course, Sally Sparrow loves old things. "They make me feel sad," she tells Kathy at the beginning of the episode. Sally's capacity to love drives her to find the Doctor and stop the Weeping Angels.
Speaking of which...
EXISTENCE ON SIGHT
The Weeping Angels are the antagonists of the episode -- the "Monster of the Week", if you will. These creatures personify the terror of things we cannot see, as well as the existential terror of what we can see.
Lonely assassins, they were called. No-one knows where they came from. They're as old as the universe, or very nearly. They've survived this long as they have the most perfect defence system ever evolved. They are quantum-locked. They don't exist when being observed. The moment they're seen by any other living creature they freeze into rock. No choice. It's a fact of their biology. In the sight of any living thing, they literally turn to stone. And you can't kill a stone. Course, a stone can't kill you either. But then you turn your head away, then you blink, and oh, yes it can!
Don't take your eyes off that.
That's why they cover their eyes. They're not weeping, they can't risk looking at each other. Their greatest asset is their greatest curse. They can never be seen. The loneliest creatures in the universe.
The Doctor explicitly states in the above dialogue that the Angels don't exist when they're being observed. This concept is explored in Jean-Paul Sartre's existentialist writings as "the look". In brief: as soon as we lay our eyes upon someone, we objectify them, quantify them by parts instead of a whole being. In the case of the Angels, they literally turn to stone when someone sees them. But as soon as you turn away, "they are fast, faster than you can imagine." When you aren't looking at them, the Angels exist and can move about freely -- and they are scary, and they are quick.
Indeed, these creatures contribute to how we are supposed to interpret the final images of the episode. Various statues from art history flash by while the Doctor gives his chilling warning: "Don't blink. Blink and you're dead! Don't turn your back, don't look away, and DON'T BLINK! Good luck." In any other context, this might be a commentary on the way that we often ignore the beauty of our own cultured history on Earth, but in this context, where statues are objectifications of actual entities, the meaning is quite different. Time kills, and no entities know this better than the statues of cultures long dead. In the above scene, Sally instructs Larry not take his eyes off the nearby Angel, for if he does, time will very quickly catch up with him.
The Doctor claims that the Angels aren't "weeping" but in the same breath calls them "the loneliest creatures in the universe." Given their grotesque faces, it's easy to assume that they aren't weeping, but one can't help but wonder about what it would be like to actually turn to stone when someone sees you -- and to zap someone into another time just by touching someone. The subtle undertone of the episode, personified in both the Angels and in Sally Sparrow's predicament, is that time is a very lonely thing to be lost in. This ties directly to the lonely nature of being the Doctor, a largely unseen character in this episode. Loneliness, and fear of death, drive everybody in this episode to the strangest of circumstances and back again, and makes "Blink" one of the most terrifying episodes of television.
(The transcript excerpt quoted above is from http://who-transcripts.atspace.com/2007/transcripts/310_blink.html -- the images are from http://doctorwho.sonicbiro.co.uk/gallery/thumbnails.php?album=37)
Moffat, S. (Writer), & MacDonald, H. (Director). (2007). Blink [Television series episode]. In P. Collinson (Producer), Doctor who. Cardiff, Wales, United Kingdom: BBC One.
Sartre, J-P. (1956). Being and nothingness: an essay on phenomenological ontology. Translated by Hazel E. Barnes. New York, New York: Philosophical Library.