The number of conscious subjects in a given entity might not always be a determinate whole number. On a wide range of naturalistic views, the processes underlying consciousness are complex enough to make it implausible that conscious subjects must always arise in countable, whole-number quantities. Whole-number-countability may be an accident of typical vertebrate biology. The fact that we cannot imagine what it is like to be 7/8 or 1.34 conscious subjects does not count against the possibility; either the imaginative demand is self-contradictory (imagine what it is like to be an entity that does not have a single, determinate what-it-is-like) or imaginability is not an appropriate test of possibility, as with bat echolocation.
The article argues that some possible minds, like the 'ancillary mind' from Ann Leckie's science fiction novel Ancillary Justice, occupy a grey zone between a single mind and a communicating group, making them neither clearly one person nor many. This challenges standard conceptions of personal identity and subject individuation. The authors suggest that if such minds defy discrete countability, some actual minds on Earth might similarly blur the line between introspection and communication. They propose extending Kammerer and Frankish's research programme to study not only possible forms of introspection but also mental activity that lies intermediate between introspection and communication.