In the Doctor Who episode "Blink", the Doctor tells Sally this about the Weeping Angels:

They are quantum-locked. They don't exist when they're being observed. The moment they are 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.

Towards the end of the episode the Doctor then traps the four Angels by having them all facing each other after the TARDIS has dematerialised. If the Angels cease to exist while being observed, then how can they be observing each other while locked into stone? If the observation to trigger the quantum-lock counts as 'In the sight of any living thing', then they surely aren't actually trapped as when they're stone they don't exist so aren't observing one another, and so long as they move one at a time they could escape the formation the Doctor left them trapped in? Note that this question doesn't deal with how to generally defeat/damage an Angel in its quantum-locked state, but rather the very specific case and nuanced trap presented in this episode.

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    By definition, each Angel is an observer, else they'd not know when to "unlock." So even a locked Angel is observing enough to lock other Angels. Therefore perhaps the question really is, how do the Angels manage to not lock each other up most of the time?
    – gowenfawr
    Nov 15, 2018 at 16:08

1 Answer 1


Rapidly alternating states. I am assuming that the logic of observation occurs instantaneously. Also, for simplicity sake, let's say one thousanth of a second is the smallest unit of time.

0.001s: TARDIS disappears

0.002s: With the tardis gone, all the angels are now looking at each other. They turn to stone

0.003s: with no observers left, the angels become living observers again.

0.004s: with no time to process input or to move, they turn back to stone, as the "observation" process occurs instantly

Rinse and repeat for however long you want. The logic of the angels is kind of flawed and leaves holes like this. Another hole in the logic is: when the two humans stood up, how did they, at least accidentally, block the observation of one of the angels? There is, again, assumptions that you can make to answer this, but it still is just a hole the writers either did not consider or explain.

  • Theoretically, with rapidly alternating states, when two angles look at each other, they can move at 1/2 speed (pulse-width modulated existence). However, if "locking" or "unlocking" takes any measurable amount of time, their movement would be effectively reduced to a complete stop. Nov 15, 2018 at 20:51
  • i would expect them to "blink" with some quantum noise. So there is a chance for one Angel to be alive while others are still stoney, thus freeing the one. Nov 27, 2018 at 21:50

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