[I briefly had a different piece up tonight discussing a conference, but the organizers asked me to hold off on writing about it until they've put up their own synopsis. It will be back up eventually; please accept this post instead for now.]
In Jewish legend, the Chamber of Guf is a pit where all the proto-souls hang out whispering and murmuring. Whenever a child is born, an angel reaches into the chamber, scoops up a soul, and brings it into the world.
In the syncretist mindset where every legend has to be a metaphor for the human mind, I map the Chamber of Guf to all the thoughts that exist below the level of consciousness, fighting for attention.
We already know something like this happens for behaviors. From Guyenet's The Hungry Brain:
How does the lamprey decide what to do? Within the lamprey basal ganglia lies a key structure called the striatum, which is the portion of the basal ganglia that receives most of the incoming signals from other parts of the brain. The striatum receives "bids" from other brain regions, each of which represents a specific action. A little piece of the lamprey's brain is whispering "mate" to the striatum, while another piece is shouting "flee the predator" and so on. It would be a very bad idea for these movements to occur simultaneously – because a lamprey can't do all of them at the same time – so to prevent simultaneous activation of many different movements, all these regions are held in check by powerful inhibitory connections from the basal ganglia. This means that the basal ganglia keep all behaviors in "off" mode by default. Only once a specific action's bid has been selected do the basal ganglia turn off this inhibitory control, allowing the behavior to occur. You can think of the basal ganglia as a bouncer that chooses which behavior gets access to the muscles and turns away the rest. This fulfills the first key property of a selector: it must be able to pick one option and allow it access to the muscles.
So in the process of deciding what behavior to do, the (lamprey) brain subconsciously considers many different plausible behaviors, all of which compete to be enacted. I don't know how this extends to humans, but it would make sense that maybe only the top few candidate behaviors even make it to consciousness, with the rest getting rejected without conscious consideration.