Timothy Taylor has an interesting entry in this year’s “Edqe Question” idea-fest. It has the ungainly title, Polythetic Entitation. He attributes the idea to the late David Clarke:
Clarke argued that the world of wine glasses was different to the world of biology, where a simple binary key could lead to the identification of a living creature (Does it have a backbone? If so, it is a vertebrate. Is it warm blooded? If so, it is a mammal or bird. Does it produce milk? … and so on). A wine glass is a polythetic entity, which means that none of its attributes, without exception, is simultaneously sufficient and necessary for group membership. Most wine glasses are made of clear glass, with a stem and no handle, but there are flower vases with all these, so they are not definitionally-sufficient attributes; and a wine glass may have none of these attributes—they are not absolutely necessary. It is necessary that the wine glass be able to hold liquid and be of a shape and size suitable for drinking from, but this is also true of a teacup. If someone offered me a glass of wine, and then filled me a fine ceramic goblet, I would not complain.
Taylor is an archaeologist as was Clarke. They face the problem of how to identify cultural objects without knowing how they are used. An object’s physical characteristics generally do not speak unequivocally, hence the term polythetic (vs. monothetic). Thus:
Asking at the outset whether an object is made of glass takes us down a different avenue from first asking if it has a stem, or if it is designed to hold liquid. The first lumps the majority of wine glasses with window panes; the second groups most of them with vases and table lamps; and the third puts them all into a super-category that includes breast implants and Lake Mead, the Hoover dam reservoir. None of the distinctions provides a useful classificatory starting point. So grouping artefacts according to a kind of biological taxonomy will not do.As a prehistoric archaeologist David Clarke knew this, and he also knew that he was continually bundling classes of artefacts into groups and sub-groups without knowing whether his classification would have been recognized emically, that is, in terms understandable to the people who created and used the artefacts. Although the answer is that probably they did have different functions, how might one work back from the purely formal, etic, variance—the measurable features or attributes of an artefact—to securely assign it to its proper category?
What matters for proper classification are the attributes with “cultural salience” (Taylor’s term).
Now cultural salience is how I define the genetic elements of culture, which I have taken to calling coordinators. Coordinators are the culturally salient properties of objects or processes. In a terminology originally promulgated by Kenneth Pike, they are emics (notice that Taylor uses this terminology as well).
One thing that became clear to me in Dan Everett’s Dark Matter of the Mind (see my review in 3 Quarks Daily) is that a culture covers or paints (other terms of art I am considering) their natural environment with coordinators. Thus Everett talks about how, even after he’d been among the Pirahã for a couple years he simply could not see the jungle as well as they did. They were born and raised in it; he was not. Features of the jungle – creatures and events – that were obvious to the Pirahã because they had learned to identify them, that were culturally salient to the Pirahã, were invisible to Everett. They may have been right in front of his (lying) eyes, but he couldn’t discern them. They were not culturally salient to him, for his mind/brain had developed in a very different physical environment.
The polythetic nature of cultural artfacts is closely related to what I have called abundance elsewhere. The phenomena of the world have many properties; they are abundant. Only some of those properties will even be perceptually available; after all, our ears cannot hear all sounds, our eyes cannot see all electromagnetic radiation, etc. Of the perceptually available properties, only some will be culturally salient. This is as true for natural objects as for cultural artifacts and activities.
A difficult and interesting question for cultural evolution. I don’t think focusing on the phenotype (in this case the composition of the wine glass) is the most fruitful approach. Zoology, to the best of my knowledge, has abandoned categorization by phenotype, which was always problematic, in favor of the genotype–DNA. The question is, what is the genotype in artifacts, or indeed in cultural evolution generally? Sadly, I don’t have an answer, only speculations, but I do think this is the most pressing issue in the field of cultural evolution. What is actually evolving? It is not the wineglasses themselves, they are an effect not a cause.