Hope here needs a humble hand.

Somewhere in my apartment, there's a sock. Somewhere in my apartment, there might or might not be another sock. Such is the crux of knowing exactly where one sock is and being uncertain about the other half of the pair. I don't know where it'd be other than inside my apartment, anywhere, under some cushions or in the freezer or rolled up with some towels.

If it's in my apartment instead of anywhere else in the world, I've at least narrowed down where to look. I'm going to start with that before expanding the search radius.