Original sentence: Though esoteric and exoteric approaches are sometimes mixed, it is believed by some modern interpreters that many alchemical authors "are not concerned with material substances but are employing the language of exoteric alchemy for the sole purpose of expressing theological, philosophical, or mystical beliefs and aspirations
Edited sentence: Though esoteric and exoteric approaches are sometimes mixed, it is clear that some authors "are not concerned with material substances but are employing the language of exoteric alchemy for the sole purpose of expressing theological, philosophical, or mystical beliefs and aspirations