While largely fleshed out in Water Belongs to the Dead: Heart of the Witch, there are a few things in the world Ted inhabits that can be clarified here in the auxiliary chapters.
This world is called Ad Rath, which means, quite literally, All (Ad) Land (Rath) and this is just as unimaginative from the inhabitants as calling our planet, well, Earth. The reason why land specifically is mentioned comes from the old, fading superstition that holds water as some kind of a portal to the afterlife, or maybe afterlife itself. Again, this is elaborated in WBttD:HotW, if you have the time and energy to read it, it will be most enlightening considering that it decipts an earlier period in time, an era of high magic and superstitious beliefs.
Then the reason for the similarities between Ad Rath and Earth. Why is the sun the sun? Why is there a single moon, like on Earth, and why are some characters named John and others have fantasy names?
Well – there is a concept I have often thought about regarding the possibility of multiple universes. What if there is a world that shares the same mythological phenotype with our dear green and blue orb? What if the building blocks of reality are not only those that hard science tries to make sense of, but instead, psychological and archetypal elements as well?
If there are infinite possibilities, then why couldn't there be a world that was so much like our world, yet distinctive in some ways? Many of us have had nightmares about, say, shadow men. We have had those dreams independent of each other, maybe because the very concept is integral to human nature.
If there is a blueprint of what it means to be human in the very fabric of reality, perhaps there can be humans in multiple different dimensions. While the people of Ad Rath might not be knowledgeable about our naming traditions, they have their own reasons for calling someone John.
Maybe there is a common thread in all the sovereign moons over human-infested landscapes. Maybe humans here, and there as well, tend to place the divine feminine right next to the glorious light of that orb, and maybe it does not matter where we come from.
The moon you see can possibly be the same moon that Serenica has prayed to, the same moon that sees Ted's evil deeds, maybe there are so many moons, made of different atoms, yet in spirit, the same thing – goddess, woman from the time before women, occult, hidden, secret, beauty, reflection.
Fear and love exist in multiple dimensions.