metal into gold. This viewpoint was a matter of much debate for alchemists of the time, and he defended it in several of his writings. Though he did discover several new chemical processes, he tended to be more of a theoretician, and he leaned toward traditional Aristotelianism rather than Paracelsian alchemy.

He was an opponent of Paracelsus on the grounds of Paracelsus' disrespect for ancient thought, magnification of personal experience above others' experience, overstatement of the didactic function of nature, use of magical words