I think an important part of this is the label that the network creates itself. So, in your example of "four legs and fluffy = 'animal'", that label of "animal"

I think an important part of this is the label that the network creates itself. So, in your example of "four legs and fluffy = 'animal'", that label of "animal" must be a completely computer-created label. Not necessarily using the word "animal", or using any kind of identifier that humans would use. A completely artificial grouping, or domain, that is identified by the computer on its own, and maintained and stored as a potentially useful label for future use.