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The doctrine of signatures is a philosophy shared by herbalists from the time of Dioscurides and Galen. This doctrine states that herbs that resemble various parts of the body can be used to treat ailments of that part of the body. Examples include the plants liverwort; snakeroot, an antidote for snake venom; lungwort; bloodroot; toothwort; and wormwood, to expel intestinal parasites. A theological justification was made for this philosophy: "It was reasoned that the Almighty must have set his sign upon the various means of curing disease which he provided."^[1] The concept is still reflected in the common names of some plants whose shapes and colors reminded herbalists of the parts of the body where they were thought to do good. Scientists see the doctrine of signatures as superstition. There is no scientific evidence that plant shapes and colors help in the discovery of medical uses of plants.^[2] In similar doctrines from India, the sage Agasthiar is supposed to have had the capability to converse with plants to thus obtain from the plants which ailments and diseases they, the plants, could ameliorate and even cure.

History [edit]

Paracelsus (1491–1541) developed the concept and published it in his writings. During the first half of the 16th century, Paracelsus traveled throughout Europe and to the Levant and Egypt, treating people and experimenting with new plants in search of more treatments and solutions. As a professor of medicine at the University of Basel, he dramatically burned classical medical texts by Theophrastus, Galen, Dioscorides and Avicenna, but not the works of Hippocrates.^{[citation needed]}

The writings of Jakob Böhme (1575–1624) spread the doctrine of signatures - Böhme suggested that God marked objects with a sign, or "signature", for their purpose.^[3] A plant bearing parts that resembled human body-parts, animals, or other objects were thought to have useful relevance to those parts, animals or objects. The "signature" may also be identified in the environments or specific sites in which plants grew.

In Christianity [edit]

Christian European metaphysics expanded this philosophy in theology. According to the Christian version, the Creator had so set his mark upon Creation, that by careful observation, one could find all right doctrines represented (see the detailed application to the Passionflower) and even learn the uses of a plant from some aspect of its form or place of growing.^{[citation needed]}

A theological justification was made for this philosophy: "It was reasoned that the Almighty must have set his sign upon the various means of curing disease which he provided."^[1]

For the late medieval viewer, the natural world was vibrant with images of the Deity: "as above, so below," a Hermetic principle expressed as the relationship between macrocosm and microcosm; the principle is rendered sicut in terra. Michel Foucault expressed the wider usage of the doctrine of signatures, which rendered allegory more real and more cogent than it appears to a modern eye:

"Up to the end of the sixteenth century, resemblance played a constructive role in the knowledge of Western culture. It was resemblance that largely guided exegesis and the interpretation of texts; it was resemblance that organized the play of symbols, made possible knowledge of things visible and invisible, and controlled the art of representing them." (The Order of Things , p. 17)

Jakob Böhme (1575–1624), a shoemaker of Görlitz, Germany, claimed to have had a profound mystical vision as a young man, in which he saw the relationship between God and man signaled in all things. He wrote Signatura Rerum (1621), translated into English as The Signature of All Things, and the spiritual doctrine was applied to the medicinal uses that plants' forms advertised.

In herbalism [edit]

The doctrine of signatures is a philosophy shared by herbalists from the time of Dioscurides and Galen. This doctrine states that herbs that resemble various parts of the body can be used to treat ailments of that part of the body. Although the doctrine of signatures was formalized in early modern times, the theme of natural objects' shapes having significance is a very old one and is not confined to Western thought. Examples include the plants liverwort; snakeroot, an antidote for snake venom; lungwort; bloodroot; toothwort; and wormwood, to expel intestinal parasites. The occasional resemblance of mandrake root to a human body has led to its being ascribed great significance (and supernatural powers) since ancient times and in many places.^[4] The 17th-century botanist and herbalist William Coles (1626–1662), author of The Art of Simpling and Adam in Eden, stated that walnuts were good for curing head ailments because in his opinion, "they Have the perfect Signatures of the Head". Regarding Hypericum, he wrote, "The little holes whereof the leaves of Saint Johns wort are full, doe resemble all the pores of the skin and therefore it is profitable for all hurts and wounds that can happen thereunto."^[3] Nicholas Culpeper's often-reprinted Complete Herbal takes the doctrine of signatures as common knowledge, and its influence can still be detected in modern herbal lore.^{[citation needed]}

Some -wort plants and their signatures [edit]

• Lousewort, Pedicularis - thought to be useful in repelling lice
• Spleenwort, Asplenium - thought to be useful in treating the spleen
• Liverwort, Marchantiophyta - thought to be useful in treating the liver
• Toothwort, Dentaria - thought to be useful in treating tooth ailments
• Hedge woundwort, thought to have antiseptic qualities
• Lungwort - thought to be useful in treating pulmonary infections

Alternative medicine [edit]

Similarity-based thinking is encountered in alternative medicines such as homeopathy and TCM.

In fiction [edit]

In A Hat Full of Sky, a Discworld novel for young adults by Terry Pratchett, an exaggerated form of the doctrine of signatures results in many plants being equipped with a text in tiny letters (and bad spelling) explaining what they may be good for, and sometimes including warnings similar to modern labels on drug or food items. The main character, Tiffany Aching, questions the usefulness of the text on a walnut shell: "may contain NUT". While this is a very minor theme in the novel, Pratchett discusses the actual historical belief in his afterword. The phrase "signatures of all things" appears in the beginning of episode 3 in James Joyce's novel Ulysses. The character Stephen Dedalus walking along the beach, thinking to himself "Signatures of all things I am here to read, seaspawn and seawrack, the nearing tide, that rusty boot."

In Season 6, Episode 1, "The Soul of Genius", of Lewis, a British television detective drama made as a spin-off from Inspector Morse, the Doctrine of Signatures is explained and a chemist attempts to develop a cure for his wife's skin cancer from the seed pods of the Burnham tree because the tree's yellow flowers are the color of skin.

Scientific skepticism [edit]

The signatures are described as post hoc attributions and mnemonics.^[2] Their mnemonic status is of value in creating a system for remembering actions attributed to medical herbs.

See also [edit]

• Augur
• Divination
• Magical thinking
• Naturalistic fallacy
• Pictogram

References [edit]

External links [edit]

• The doctrine of signatures: a defense of theory in medicine - Scott Milross Buchanan, first published 1938