Last updated on 1 Mar 2019
All classificatory terms are impossible of exact definition. Their use always has and always will depend upon the consensus of opinion of those best qualified by wisdom, experience and natural good sense. They will never become stable; we shall never cease to amend, to change, to repudiate old and propose new, because we shall never reach the final summation of science. [S. W. Williston, “What is a species?”, American Naturalist, 495, 184–194, 1908]
So we have come a distance. Categories about the natural (i.e., the non constructed) world are not based on some naive notion of phenomena or observations, but upon experienced (that is, expert) observations. Nevertheless they can be modulated and biased by cultural and sociological factors. Let me talk now about an example close to my heart: species (and other taxonomic categories).
As is well-known (Wilkins 2009, 2018 forthcoming, Zachos 2016), scientists do not at all agree on what species are. Nor, it must be said, do they agree on what counts as sufficient evidence that two organisms are in different species. At least, not all of the time. And yet, the standard view is that species are fundamental units of evolution, ecology, and other ways we deal with the biological world. In my forthcoming book (the new edition of my 2009, now known as Species: The evolution of the idea) I argue that the very notion of a “level” of biological taxa such as species is itself the outcome of sociocultural factors – to wit, the need to work out what “kinds” meant in the Noah’s Ark story so the logistics could be rationalised [also here]. If that is the origin, why does species persist among scientists as a category?
Once, when I was still invited to attend such things, I went to a workshop that included the late John Maynard Smith, and of course I took the opportunity to ask him about species (this was very early on in my studies on the topic, so I had nothing profound to offer him), and to eat half his sandwich. I asked him what he thought they were, and his response, which I dismissed at the time, was that they were merely communicative terms, for the convenience of biologists. I now know this was (in 2000) a common response to the species problem by geneticists, but it shocked me. How could “species” help communication, if they were not referring to anything? If the category was unreal, as he suggested, then what were we talking about?
Other biologists, particularly my now colleague and coauthor Brent Mishler, had been saying this for some time: “species” was an unnecessary rank in an otherwise rankless evolutionary process. Brent, by the way, has a book out shortly after mine on this very subject. He, and other species deniers, considered the very category nonscientific. I had suggested something similar in 2003, but it was muddled. Against the deniers are the species realists, who argue that species not only exist, but that there is a “level of organisation” in biology that answers to “species”. I have had papers rejected because reviewers took it as an article of faith that there was such a level of organisation not only in this or that group, but across the entirety of biology (except, perhaps, single-celled microbes), and the editors did not challenge this.
There is a distinction between category realism and entity realism about species that needs to be attended to. Category species realism is the view that the category is real as well as the individual entities that fall within it, and it is that which I take aim at here. Entity realism is the view that, individually, the entities (as populations, lineages, etc.) that get called species are real, but the category is not natural. It occurs to me now that Maynard Smith may have been right. We can refer to individual species like Homo sapiens, Mesoneura opaca, and Alchorena ilicifolia [Ereshefsky 1998], even if they are not all of the same category or type. I can have diverse things in my pocket: a coin, a lighter, and a ticket. They do not need to be a natural kind to get referred to as “pocketed items”.
It looks very much as though species as a category is not natural in the “natural kind” sense that philosophers have been talking about since Mill. Instead it looks like the outcome of a series of more or less frozen accidents in theology, philosophy, and science, for which retrospective justifications have been given as the needs arise. In short, species is a cassowary. A purely cultural concept. Or is it? Several things mitigate this rabid reductionism. One is that species are often named and retained for centuries. Many of the species identified in the medieval period remain “good” species, for example, although their nomenclature and arrangement in relation to other species have changed a lot. It seems that good observers can identify things in the unconstructed world even in the absence of theory and method held to be essential to good science. Another is that as I noted in the first post in this series, humans tend to find levels of categorisation of the unconstructed world fairly consistently and across cultures and times.
Hence my argument, given in my coauthored (with Malte Ebach) book The nature of classification, and expanded on in the forthcoming Species, that species are phenomena. Given that natural phenomena are a reciprocal arrangement between the unconstructed world and experienced observers, and that we have a tendency to find patterns in the world, this explains why it is that we so often find species in this or that group so obvious, even though there are multiple boundary cases where they are not obvious at all. Species, and by extension to the rest of science, natural categories, are patterns we match in observational data, based on our prior experience of uncontested cases. They need not be, and often rarely are, theory-based; but they are based on the practicalities of doing natural science. In some disciplines, such as physics, one needs to be very theoretical to even observe microscale and even mesoscale phenomena; but that doesn’t mean we are forced to be theoretical in the observation of biological, geological or even astronomical phenomena; at least, not all the time.
This goes to the main question of this post series: are the categories of science in any way objective? To answer this, I need to discuss the role explanation plays in science, or at least a rough sketch of it. Next post…
A very interesting series of discussions, John. Keep them coming. I’ve been thinking about similar issues with respect to literature and literary criticism. I’m convinced that the category of literature itself is one of this intuitive categories best established by experienced observers. When those experienced observers become academics, at least some of them want to justify the category through recourse to explanatory theories of some kind. Alas, I don’t think the discipline has yet managed to cough any up.
With the biological species concept, at least in the case of animals we can interrogate individuals to find which other individuals they will attempt and be successful in reproducing with: this class sounds awfully natural to me.
I notice Gonzalez-Forero’s 2009 paper suggests we just allow boundary case animals and plants to be members of more than one (biological) species 😉
“How could “species” help communication, if they were not referring to anything? If the category was unreal, as he suggested, then what were we talking about?”
Perhaps like Americans or indeed beavers biologists are ‘mere’ social animals?
” In the fifth part the Author treats profeffedly of the genius and difpofition of the Americans, whofe uniiverfal characteriftic he affirms to be a ftupid, innate and irremediable infenfibility. Superior to the brutes, becaufe they can fpeak, and are poffeffed of hands, they are inferior to the meaneft and moft ignorant of the Europeans. They have no ideas, reflection or memory. They clap their hands to their foreheads and fhut their eyes, in order to recollect in the morning what they had been doing the night before. When under inftruction, while the mafter is deducing his confequences, they have already forgot the principles from which he draws them. In the few arts which they poffefs they Invent nothing, nor improve or perfect anything, more than the beavers of their own country.”
Use of the ‘social argument’ does have historical form in this subject and can be associated with an elitist tendency which is still a live social factor in our education systems.
If you are making a social/ cultural argument, it would be important to cover the way that argument can itself be biased by cultural and social factors.
“species is a cassowary”
Thorleifur Hauksson raises an interesting question at the end of his paper “Man as Wolf (Once More).”
“wither metaphors exploit already existing similarities or rather create them.”
Hauksson is building on Max Black’s work on metaphor which is worth citing.”The idea of a wolf is part of a system of ideas, not sharpy delineated, and yet sufficiently definite to admit of detailed enumeration. The effect, then, of (metaphorically) calling a man a “wolf” is to evoke the wolf-system of related commonplaces. If the man is a wolf, he preys upon other animals, is fierce, hungry, engaged in constant struggle, a scavenger and so on.”When deploying the social and cultural as reality altering substances may be a bias towards creationism here.
There might be fifty words for snow but thanks to computers we seem to be running out of new words – or maybe letters. I may have mentioned in the past on your blog (there’s a newish word) that I am writing a book on evolution. It’s about a second mechanism that facilitates a leap – it’s about the production of a ‘special variant’. I called this variant a Dapin. Thirty years ago (I’ve been writing the book a long time – I hope to finish it before I pop my clogs) a friend of mine had been playing at finding a new word, then checking the dictionary to find if it already existed. Dapin was not in the dictionary – he gave it to me. (I have weird friends.) A couple of months back I checked it out on Google (another newish word) only to find that it is now an acronym for a concept in protein synthesis analysis. OK, so I need a new word. I found it unbelievably difficult to find a 5 letter combination that has not been used by anybody. Try it – it’s not easy. I eventually found ‘zlexp’. I hereby claim it as mine. I pronounce it ‘zlep’ with a silent x – like the silent f in eggs. You might say there is no f in eggs. Try looking in in the fridge. (sorry about that one)
Computers spew and consume new words – people need catchy tags to catch the attention of search engines – all the advances in scientific discovery demand new terms – it is the same in politics – who on earth thought of the word Brexit – it’s a word that somehow demands a frown to say it. If there are 26 different definitions of species (your count a few years back John) then really they all need a word of their own – another 26 words gone. I quite like the idea of writing a book on evolution titled – The Origin of … … … then 23 more words.
How many words – short and efficient – say up to 8 letters – can be made using the 26 letter alphabet. How long will it be before all such combinations have all been used. Then we will have to go for longer and longer words, or add some new letters to the alphabet (a terrifying thought for yours dyslexic truly). It is an equally bad thought that the Inuit who finds the 51st type of snow will have a hard job naming it. Of course with PC (or without it in my case) there are two words for those most familiar with snow – one I have already used – the other, Eskimo, I’m not supposed to use. For every non-pc word, we need another. I think we are soon to run out words.
Could you elaborate with general or more examples of the natural, unconstructed world? Thinking can be outside of construction, systems and so on however, the natural world seems to be constructed. Unless I am not understanding the exact definition of the “unconstructed natural world”. I am often thinking and trying to observe these ideas, elevating things outside of possible social and system influence but it’s not easy. As the natural world itself seems constructed and patterned. Seasons as one example. Night and day to which we number with a 24 hour time frame. Birth and death of life. It seems extremely constructed and on a system of its own which seems to be overall effective. Unless unconstructed world can mean what has not been observed or can’t be explained.
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