Sol oritur occasus nescius
what does nescius refer to? Maybe diagramming the sentence is all I need, because I don't follow the grammar.
If the idea is that the Sun rises not knowing when or whether it will set, then I'd expect the sentence should be Sol oritur occasum nesciens. If the idea is that when the Sun rises, no one knows when or whether it will set, then I'd expect Sol oritur occaso nescio (although I think first of nescio as the verb "I don't know").
But the word is occasus, which could be a noun or an adjective. If a noun, that would tend to put it into a different case, as above. So maybe it's an adjective modifying Sol. But then what does the sentence mean—The Sun rises, having already set, without knowing how it rises? That could make sense, given that the rest of the poem runs through religious paradoxes involving a single thing appearing in two forms that somehow interact with each other. I don't know the idioms and grammar well enough to say.