Kafka on the Shore

In Kafka on the Shore, talking cats are symbols for the existence of a parallel world. After his childhood coma, Nakata finds he has become a shell of a person, suffering cognitive impairment and losing most of his desires. However, he gains the ability to speak with cats. For much of the novel, this curious detail goes unexplained. However, when Hoshino discovers that he too can talk to cats, Hoshino learns from Toro that they can hear each other because they are "on the border of this world, speaking a common language." Having opened the portal to the other world by flipping the entrance stone, Hoshino becomes more like Nakata, existing on the borderline between standard reality and the supernatural alternate reality that exists alongside it.