Ethshar is an artificial world......which was built by English-speaking humans, sorcery is Magitek based on their technology, and Ethshar gods are AIs. What do we know about sorcery? 1) It uses devices ("talismans"). 2) Its terms and commands are garbled English words (yz'raksis nyuyz'r = user access: new user, for example). 3) The World uses a life-support system, which converts poisonous gases into breathable air. This system is a huge sorcerous talisman. So, it looks quite possible that English-speaking humans created the World with technology, and later the inhabitants learned to manipulate this technology a bit - which is the art of sorcery. As for Ethshar gods being AIs, that's just a guess, but I remember the author saying that they have to respond if called upon in the correct way. That can be confirmed or Jossed by a short story when a theurgist accidently summons a god from another world - namely, Santa Claus from Earth.
WMG / The Legends of Ethshar
The Legends of Ethshar