The Doctrine of Signatures is a classic mode of knowing within herbalism. Roughly speaking, it posits that plants contain some aspect which resembles the human organ they have an efficacious power over.
Hepatica (Hepatica nobilis) is one example: the lobes of its evergreen leaves suggest the human liver, and thus is its medicinal use revealed under the Doctrine of Signatures.
Vincent Abraitys recalls the similar lore surrounding Eyebright (Euphrasia sp.):
"The purple and yellow spots which are upon the flowers of eyebright very much resemble the diseases of the eyes or bloodshot"
The Doctrine of the Signatures dates to the 17th and 18th centuries in Europe, when "a new breed of commercial herbalists began to vulgarize sympathetic magic..." (Mabey, 1988)
I'm going to start stringing together some conjectures now.
To my mind, the 17th and 18th centuries in Europe coincide with the tail end of a long campaign to eviscerate the connection between people and the land, most especially their spiritual connections. Pagans, heretics and finally witches had been persecuted for centuries, and both the Christian and emergent scientific philosophies posited a vast gulf between "man" and the rest of nature.
I can't help but suspect that the Doctrine of Signatures was a flawed attempt to pseudo-scientifically re-systematize the remaining scraps of herbal lore which had not been lost in the long extinguishing of pagan knowledge which was the Dark Ages.
I suspect that it is a poor caricature of the intense objective study and also the sophisticated spiritual techniques which "pagans" utilized to understand the powers of plants.
Now, a similar project is underway, globally. We are trying to rescue and understand the final scraps of primitive knowledge that were not extinguished in the even greater orgy of destruction which took place on a worldwide scale over the last five centuries.
When I read that Native Americans believed an herb to be efficacious in one way or another, because of the Doctrine of Signatures, it sticks in my craw.
When we look at the myths and symbolisms of oral cultures from the perspective of a literate culture, I think we fundamentally misunderstand their role.
We also like to believe that "primitive" cultures lacked the objective and analytical modes of thinking which we so pride ourselves in. That doesn't help our understanding very much.
I've frequently been confused myself. As a long-time student of anthropology, I have a pretty strong conviction about the sophistication of "primitive" peoples when it comes to issues of awareness and analysis of the ecosystem they lived in.
I'll gladly argue that most "primitive" peoples held far more complex, detailed, and objective notions of the natural world than we do.
On the other hand, I have sometimes been confused when trying to tap into this knowledge myself, utilizing those sparse and sometimes scattered documents which remain of, for example, Native American natural lore.
As much as I enjoy reading mythology, myths are frequently oddly lacking in detail, sparse, riddle-like, and perplexing. They seem always to be missing something, as if they are distilled down and have lost the skin and flesh which once cloaked the skeleton of truth I am left reading.
In a lot of ways, they remind me of the Doctrine of Signatures: arbitrary and overly-simplistic.
I recently read a fantastic book which I will now try to utilize to untangle why myths are often so vacant for me, and also to further question the "Doctrine of Signatures".
In The Spell of The Sensuous, author David Abram traces our loss of sensual engagement with the natural world through recent history, as literary modes of knowledge supersede oral modes. He makes a dazzling case for writing mediating our experience of the phenomenal world, diminishing it relative to the unmediated experiences of time and space inherent to oral cultures.
The book helped me to better understand the myths I've read by placing them within the imperatives of an oral system of knowledge transmission.
I will quote verbatim for while, starting with Abram's quotation of a Koyukon story from the Distant [mythical] Time:
When the burbot [ling cod] was human, he decided to leave the land and become a water animal. So he started down the bank, taking a piece of bear fat with him. But the other animal people wanted him to stay and tried to hold him back, stretching him all out of shape in the process. This is why the burbot has such a long, stretched out body, and why its liver is rich and oily like the bear fat its ancestor carried to the water long ago.*
Abram begins a discussion of this story:
Anthropologists have tended to view such stories from the Dreamtime or Distant Time as confused attempts at causal explanation by the primitive mind. Here, however, in light of our discussion regarding orality and literacy, such stories can be seen to serve a far more practical function.
Without a versatile writing system, there is simply no way to preserve, in any fixed, external medium, the accumulated knowledge regarding particular plants (including where to find them, which parts are edible, which poisonous, how they are best prepared, what ailments they may cure or exacerbate), and regarding specific animals (how to recognize them, what they eat, how best to track or hunt them)...
...Such practical knowledge must be preserved, then, in spoken formulations that can be easily remembered, modified when new facts are learned, and retold from generation to generation. Yet not all verbal formulations are amenable to simple recall--most verbal forms that we are conversant with today are dependent upon a context of writing. To us, for instance, a simple mental list of the known characteristics of a particular plant or animal would seem the easiest and most obvious formulation. Yet such lists have no value in an oral culture; without a visible counterpart lists cannot be readily recalled and repeated. Without writing, knowledge of the diverse properties of particular animals, plants, and places can be preserved only by being woven into stories...
Stories, like rhymed poems or songs, readily incorporate themselves into our felt experience; the shifts of action echo and resonate our own encounters--in hearing or telling the story we vicariously live it, and the travails of its characters embed themselves into our own flesh. (Abram p. 119-120)
End Quote. Using Abram's notion of myth as, among other things, a mnemonic device for the narrative exchange of culturally vital information, I'd like to have a second glance at the "Doctrine of Signatures".
Is it possible that we (and the 17th &18th century commercial herbalists who preceded us) have mistaken a mode of transmitting and remembering information, for a mode of discovering information?
What if the aforementioned Eyebright was discovered, through objective or magical means, to have a curative effect on the eyes, and its "The purple and yellow spots which very much resemble the diseases of the eyes or bloodshot" are merely cues-- visual hints encoded in half-lost oral narratives which encoded the herbal knowledge of pagan cultures?
What if all of our perception is essentially synaesthetic, narrative, searching for connections? Wouldn't it then be easier to remember even the most objective facts by enmeshing them in an essentially metaphorical network?
As in many other things, I think our modern system of education has much to learn from the knowledge-transmission technologies of primitive peoples.
A last point, perhaps shaped more like a caveat than a spear:
In suggesting this rather functional role of myth, and in stressing the objective traditions relating to plant lore, in no way do I intend to suggest that "magic" or "spirit" had no role in the revelation of plant powers to primitive peoples. I think that they did, and in ways which are far more complex and potentially alien to us than we typically caricature.
The Doctrine of the Signatures, however, is not "magic". Insofar as it appears to be "silly" or arbitrary to us, it is as a result of the conversion of (half-destroyed) oral knowledge into a literate and (pseudo-) scientific context.
Lost in the translation, as they say?
*This Koyukon story is quoted from Make Prayers to the Raven, an excellent ethnography/natural history of the boreal forest.