There are a lot of great threads on this topic already, but I keep getting lost down the rabbit hole so I thought I would start a new thread. These are my thoughts on how the world operates.
I believe that this is another planet in our future after Humanity leaves Earth, or maybe a future Earth after a High Tech Civilization fails and we live in the fallout of a WWIV scenario. This is supported by the subtle refs to our history (names, the Olympian Fury joke, Semper Fortitudo, among many others) We attempt to master this new world, however the ether is something that simply doesn't/didn't exist here/now and changes a lot of basic things, including the iron rot and the madness. I don't know enough chemistry to try to explain why metals would oxidize at a different rates but I'm sure someone could. The fascinating thing for me is how the ether seems to have an affect on consciousness. Sunlight on the ether will drive men mad, but unenergized ether does not harm. Preddy is clearly able to hold discourse with Folly. Which lends credence to Ferrus' claims to speak to the ship as well. (I love the idea of a drunken ethrerealist talking to a grouchy wounded ship.) I believe it has less to do with anything special about the power core other than its age. It has had a longer time interacting with the etheric currents than almost any other ship in the sky. Another normally inanimate object that could have a soul is a library. I know a Terry Pratchett level of book love could explain this away but I think it is a part of the explanation for Preddy and eventually the Enemy. But say that a person writing a book, pouring themselves out, focusing, loving, sweating, crying over a book would leave a small scrap of their identity literally with that book. All of these book are hand written and copied. Now imagine the same level of devotion, dedication and labor went into an actual vessel like Predator, would all the scraps of the different men, thousands of years of Albion crewmen and Captains, form that same whole that Ferrus mentions to Folly in the Great Library?
My personal theory is that Ferrus was a Marine, specifically a gunner, began going mad on his tour, kept a weapon's crystal from a cannon for his cane and became an apprentice etherealist. He lost his first Padawan to the Enemy. She now calls herself Cavendish and her line to Sark near Bridget in the tunnels about drawing them out of Heaven is, to me, a spaceship/station in orbit waiting the millenia needed to terraform/heal this world by the custodians they left in the Spires. The Builders made the Spires to ground the etheric currents for that purpose, even using that power to assist in running systems to keep the custodians alive. But they didn't understand the intelligence enhancing quality of the ether and have been slowly rousing the awareness of the actual planet and its anger and resentment. Or maybe just an old weapon left around from the WWIV. And once those left planet side learned to grow cyrstals hydroponically instead of just meat and veg, the population swells, gets out of control and implodes; resulting in a massive loss of knowledge and a slow cultural rebuilding process that varies from spire to spire.
Just a theory.