Paracelsus (1493–1541) shared the Neoplatonic beliefs of most alchemists: decay is the beginning of all birth; prime matter separates out of ultimate “immaterial matter” and human creativity repeats this process; time is a cycle composed of force and growing; and above and below, or heaven and earth, are the same in form.

However, Paracelus replaced the planetary theory of “humors” with a chemical one: salt, sweet, bitter, sour, and the fifth element—or quintessence—life. His term Ens natural referred to the balance of the chemical humors, and Ens spirituale was the balance of the mind. Unlike many of his colleagues, Paracelsus did not think that insanity was caused by demons or that nightmares represented sexual intercourse with succubi. He taught that the mind can create diseases in itself, the body, or in the minds or bodies of others via hypnosis, magic, or ill will. He thought that most diseases are curable evils but that no doctor can correct Ens Dei, or the will of God.

Paracelsus was accused of heresy for his Neoplatonic notion of prime matter and for asserting that illness was not evil. (Prime matter contradicted the idea that God created everything; also, saying that illness was not evil left no room for the devil.) But, after his death, his birthplace became a shrine for Roman Catholics.