This can be stated in active form. AT: "I think of the world as already dead" or "I treat the world like a criminal God has killed on a cross" (See: [[rc://en/ta/man/translate/figs-activepassive]])
The words "have been crucified" are understood from the phrase before this. AT: "and I have been crucified to the world" (See: [[rc://en/ta/man/translate/figs-ellipsis]])
Possible meanings are 1) the people of the world, those who care nothing for God or 2) the things that those who care nothing for God think are important.