Paracelsus

He was baptised Theophrastus von Hohenheim, near Einsiedeln in Switzerland, in 1493 or 1494, the year is genuinely unresolved. The familiar four-part name is a composite he never used: Aureolus is contemporary but attaches to him late, and Philippus is posthumous, appearing first on his tombstone. The by-name Paracelsus shows up around 1529 and may not be his own coinage; it is read either as a claim to surpass the Roman medical writer Celsus or as a Latin play on Hohenheim, celsus meaning high.

The claim that the English word bombastic derives from his family name Bombast is false, and it is repeated constantly, including in otherwise careful books. Bombast is cotton wadding, the padding in a doublet, from Old French bombace and ultimately Greek bombyx, and it acquires the figurative sense of inflated language in the 1580s, decades after his death. Bombast was a genuine name in his father's family, which is why the story is plausible enough to survive. It is a coincidence.

The habits behind the legend are real enough. He lectured in German rather than Latin, which was close to scandalous, and at Basel in 1527 he publicly burned the books of Avicenna and Galen, announcing that his own experience was worth more than a thousand years of authority. He was run out of Basel within the year and spent most of his life travelling and quarrelling.

It is easy to file Paracelsus as a magical thinker with lucky guesses. The more accurate account is that his metaphysics and his method were entangled, and both produced results.

He replaced the four humours with the tria prima, salt, sulphur and mercury, understood as principles of body, soul and spirit as much as substances, and treated disease as an external agent attacking a specific organ rather than an internal imbalance of fluids. That is a genuine shift toward disease as a thing with a cause and a seat. He introduced mineral and chemical remedies into a pharmacy that had been almost entirely herbal, and is the founder of what became iatrochemistry and eventually pharmacology. He described the occupational lung disease of miners as a disease of miners rather than a punishment, which is close to the beginning of occupational medicine. He named zinc.

The line most quoted from him is also the soundest: all things are poison and nothing is without poison, and only the dose makes a thing not a poison. That is the dose-response principle, and it is the foundation of toxicology.

The rest of the system is not detachable from this and should not be quietly dropped. He held to the doctrine of signatures, that a plant's form advertises its use; to the archeus, an inner alchemist governing digestion and growth; to a cosmos in which the human being is a compressed image of the whole; and to a populated nature of elemental beings, his treatise on nymphs, sylphs, pygmies and salamanders is the source from which the four-element scheme of elementals entered Western occultism and, through it, most modern fantasy. Walter Pagel's and Charles Webster's studies are the standard treatments, and both insist on the same point: the medicine and the magic were one project, and separating out the parts that worked is our operation, not his.