Swiss physician, chemist, alchemist, and mystic, Philippus Aureolus Paracelsus spent his life traveling, healing, teaching, and writing. The son of a physician, he was attracted to the study of metallurgy, and his medical practice emphasized the use of chemical over herbal remedies. Paracelsus rejected the traditional medical authorities of Greek and Arabic science, such as Galen, Avicenna, and Celsus (his name can be interpreted to mean "beyond Celsus"). Instead, he steeped himself in the alchemical and Hermetic literature (the body of works attributed to the fabled Hermes Trismegistus), developing a full-blown philosophy grounded on the alchemical theory of the human as the microcosm, and of the identity of the humors with the essential chemical principles of nature. Paracelsus's teachings thus juxtapose originality and innovation with acceptance of arcane and occult beliefs and practices, a combination encountered in many Renaissance thinkers.