"Trying to define the undefinable": is iNat too focused on species?

This is not even remotely a unique critique. Species concepts and “what is a species” have been major topics of debate in among scientists and philosophers of science for generations.

The article was a bit glib. I’m not impressed.

“A Linnaean binomial seeks to circumscribe an entity exactly, and when a subset of that entity doesn’t quite fit the tight circumscription, we feel that we must propose another one to circumscribe that subset separately”

No, that’s not true. A Linnean binomial is a convenient handle for a group of organisms so that people have a way to refer to them. While names are formally circumscribed, often, traditionally, on morphology alone, they are always in flux as we get more information about how the organisms in question interbreed (or not – for example, asexual species, e.g. some Daphnia) and how genetically distinct they are from one another. Fossils are a whole other ball of wax. Where to draw the line is very different in different taxonomic groups.

(I have a PhD in this)


@DanielAustin I get what you’re trying to say here, but as someone trained in philosophy, that’s not what actually serious philosophers do. Philosophers could in fact offer some useful perspectives on both the species question, and the color question you raise.

In fact, you seem to be unconsciously paraphrasing Wittgenstein’s Philosophical Investigations when you say “for all their imprecision…color words serve us well.” Wittgenstein is also useful for dealing with the question of the meaning of the word “species”: “For a large class of cases of the employment of the word ‘meaning’ – though not for all – this word can be explained in this way: the meaning of a word is its use in the language.” That helps explain the use of the word “species” in natural language. With that in mind, it should become clear that the natural language meaning of “species” differs somewhat from the scientific meaning of the word: the scientific definition of the word can vary depending on the purpose of the scientist using it. So, for example, for some biologists species can be adequately defined in terms of morphological characteristics, because that meaning helps them test certain hypotheses about the organisms they’re interested in; while for other biologists, DNA evidence is of critical importance, given the hypotheses that they are investigating. Pierce’s philosophy can be useful here, and it could be argued that Pierce’s insights into scientific method and logic have been assimilated by science. We could probably drag in Godel’s advances in logic somewhere too, but now I’m getting way outside my area of expertise — my area is ethics, not epistemology, logic, and philosophy of science.

Finally, I might add that while it can be fun to trash-talk other academic disciplines, remember that other academic disciplines are also trash-talking you. No need to repeat some of the trash-talking jokes physicists and mathematicians tell about biologists :wink: Bottom line, iNat should be a place where we treat each other with respect.


No disrespect intended to philosophers at all. (I have an MPhil myself, and as both my degrees were in Linguistic Science, Wittgenstein is indeed more familiar to me than probably any other – as an aside, I used to live a 5-min walk from the cemetery where he’s buried.) But I’ve also been in enough philosophy seminars and lectures to know that many philosophical arguments can get quite silly when taken to their extremes. Perhaps I should have said self-styled philosopher or wannabe philosopher to clarify that I was mocking the foolish thought process I outlined rather than an entire discipline.

Anyway, you make some interesting points, so thanks for those. (Oh, and as for trash-talk by physicists/mathematicians of biologists, I guess I’ve spent more time dishing that out than receiving it! Although biology is forefront in my career nowadays, in fact I’ve not studied it academically since I was 16. Rather, I specialised in mathematics, physics and chemistry in my pre-university years.)


Yes, exactly this!

Broadly dismissive declarations that “species are not real” and “taxonomy is not science” become ever more frustrating.

One source of such fallacies is the number of different “species concepts” that systematists have developed based on observed properties of organisms and their populations. But why, one might ask, are there not also 21 “genus concepts” or 47 “family concepts”? Why the difference? Because the taxonomic ranks of genus and family are examples of truly arbitrary human constructs, and such concepts would have little utility at those ranks.

  • Digression: as a grouping of related species, a single genus (for example) could encompass an entire kingdom at one extreme, or each species could be given its own genus at the other extreme. Either of those extremes is maximally uninformative, especially since a genus name forms part of the nomenclature by which we communicate about related species. So we have gravitated instead toward something in the middle - diagnosable groups of related species that most usefully convey information about the similarities among the included species and the differences from other such species groups. The only thing about supra-specific taxonomic ranks susceptible to hypothesis testing and falsifiability is whether they represent monophyletic, paraphyletic, or polyphyletic groups of extant species. But which such groups get chosen to be ranked as genera remains an arbitrary and utilitarian choice. Not necessarily so with species.

Taxonomy may sometimes be practiced unscientifically, but it is not inherently unscientific. All species taxa start as hypotheses, usually based on the same phenotypic discontinuities by which Linnaeus developed his classification. When one is explicit about the species concept being applied, such hypotheses are subject to repeatable experimental testing and falsification, just like in any other experimental science. The fact that most species hypotheses have yet to be tested reflects only the enormity of the task relative to available resources, not anything arbitrary or unreal about what is being hypothesized.

Likewise, the number of species concepts available with which to frame hypotheses reflects only the real diversity of reproductive and evolutionary processes in nature - two of the most fundamental aspects of all living organisms. That there is not just one “way of being a species” for all organisms may be inconvenient to our need for simplicity, but that in itself is a good indicator that species are not arbitrary constructs - otherwise we would have pursued the imposition of such simplicity instead of observing the actual variation in nature. The fact that species do not encompass comparable sets of organisms and genetic diversity across all branches of the tree of life should surprise no one, and does not make them arbitrary or any less real.

Because species names also serve as a primary human communication tool for our common understanding of natural diversity, there always has been, and always will be, a tension between species hypotheses rooted in experimentally testable properties of organisms on the one hand, and those that are observable by ordinary means accessible to most human beings on the other hand. (I would argue that this tension has been the other major driver - alongside different reproductive and evolutionary modes - in the development of multiple species concepts.) When biology and practicality do not coincide, we can choose to either “hijack” the species rank arbitrarily in limited situations for practical communication purposes, or to use other available taxonomic ranks for more practical communication needs. Again, this does not justify blanket assertions that “species are not real.”

  • Digression: as systematists and taxonomists became more “biologically aware” of their taxa post-Linnaeus and especially post-Darwin, it initially seemed like most of the phenotypic discontinuities that Linnaeus classified corresponded reasonably well to a “biological species concept” of

and such discontinuities continued to serve as the most accessible proxy for asserting biologically-based species hypotheses. As better and better experimental methods became available, many such hypotheses could be tested and some were falsified, often in favor of more cryptic and less easily observable species. These species were nonetheless more “real” (repeatably testable and falsifiable) than what had previously been hypothesized. With this and the constantly improving understanding of reproductive modes, evolutionary processes, and speciation mechanisms, taxonomists had no choice but to expand their conceptual frameworks for species hypotheses.

So in long answer to the question in the topic title: emphatically no, iNat is not too focused on species, for a couple of reasons. First,

And second, the species rank, as Linnaeus’s main communication tool for classifying organisms, also became post-Linnaeus the one classification rank generally accepted to have a testable biological basis in the organisms themselves. That rooting in biology will always be absolutely essential if we don’t want our taxonomy and nomenclature to become the completely arbitrary and meaningless thing some folks seem to want and hope it to be.


Meanwhile, for me, it immediately brought to mind the blue-green distinction in language (grue) and how most ‘blue’ words in Korean also have ‘exceptions’ where the word is used for things considered ‘green’ in English. Motorists here, for example, stop at a ‘red’ light and go at a ‘blue’ light while we buy both ‘blue’ jeans and ‘blue’ grapes at the supermarket. (Blue-green distinction in Korean)

And now I’m suddenly curious how much fluidity there is in/of the concept of a species across languacultures.


this seems very heavily biased language. We already have taxonomic units for more practical communication needs - subspecies.

Just because someone disagrees with you doesn’t make them ignorant.

the changes aren’t making it less arbitrary and meaningless at all. They are making it more arbitrary and meaningless. It’s literally completely meaningless in a lot of cases because taken to where people seem to want to take it, you’d only have 5-10 people globally able to identify even the most common ‘species’.

We are nearing the point where we are going to see a rift between taxonomists and literally everyone else ranging from the public to the field ecologists who collect 95% of the data taxonomists use. That also corresponds with 95% or more of iNat users so if iNat is forced down that path it will collapse in the next 5-10 years if not sooner (you can quote me on this later if it doesn’t, i’ll buy you a beer/coffee if i ever meet you)… I already see it in the field any time i interact with other field ecologists.

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Lemme put this another way. Imagine if physicists discover a tiny particle like a quark or boson that subtly influences all matter in the universe. They discover that since each one is different, you can’t identify ANY element unless you put it in a particle collider. Carbon is actually several different elements that act completely identical except on a quantum level. Cool discovery, right? We should be excited! I’m excited! But what happens next isn’t so exciting. The physisists fan out to all chemists working in the field and loudly denounce them for using such concepts as ‘carbon’ and ‘oxygen’ in their work. They travel to industrial labs and insult people who still conduct chemical manufacturing, because they are using obsolete terms like ‘iron’. They absolutely insist that Carbon 1-3 are all recognized and loudly reject any science of any sort that doesn’t use a particle accelerator. People try to say something about how this doesn’t work, but are called tiresome, lazy, unintelligent, and uniformed. i-Chemistry, a popular site for all people to use to learn about chemistry, is co opted by a small but very vocal band of quantum physicists (who for some reason were also the only moderators on the site) disagreeing with everything and breaking the site because most people, who don’t have access to a particle accelerator, aren’t dsecribing their elements right because they can’t always identify six different oxygens with different quarks that are completely identical.

Good science? Can anyone call this better science? Or can you recognize that science on one level (quantum physics) can be really cool and worth researching without you also having to totally end all applications of chemistry by forcing things into a shut down based on semantics?

Nice analysis, @jdmore .

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You are right, I did let my personal taxonomic opinions hang out more that usual for this particular topic, guilty as charged. I don’t expect everyone to agree, and I certainly don’t label anyone who disagrees as ignorant, especially when reasoned and evidence-based.

Sorry, my intent was to express frustration rather than condescension. I edited that paragraph accordingly.

Please refrain from posting personal attacks and unwarranted assumptions about people’s personal or professional interactions.

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I apologize too, sorry. I deleted that inappropriate personal attack on my part as well. and should consider my communication method, my point isn’t to attack taxonomy as a science, just express why i think it isn’t appreciated enough how taxonomic decisions ripple elsewhere.


For plants, iNaturalist follows POWO (Plants of the World Online, based at Kew). It’s not perfect either, but a good place to start.


Wait, what? I know the ICZN defines what a “valid name” is (not the equivalent of a validly published name in botany), but I didn’t think they maintained an Animalia-wide list of subjective synonyms.

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I don’t think ICZN maintains any such list. The code just sets the rules for naming and recognition of names for animals.


And that is why these threads keep coming up, and why a lot of us get more and more frustrated. As I have mentioned before, #IdentiFriday is no longer the happiest day of the week; it is a discouraging day, knowing that my efforts to provide what observers want – the identification of their organisms – are going to be undone by the next taxon split. We have also had threads dealing with the issue of researchers who seem to think that the iNat userbase is their unpaid labor force. These things are related. Far from “connecting people with nature,” the way iNat handles taxonomy is only reinforcing the disconnection of people from nature.

Excellent analogy.


I’ve been known to complain that all these splits are inappropriate – except the ones I make.


The taxonomic splits that involve traits we can’t easily see are frustrating! Most of them have reasonable explanations. After all, organisms don’t evolve to meet our human needs for labeling. Many of these splits turn out to have good reasons, and the splits will be accepted. Some are not going to be accepted. (e.g. some splits in Avena (oats) and one in Oregon Navarrettia). It takes time to test these concepts. (For example Sedum section Gormania, which certainly needed revision but we don’t yet know if our changes are all improvements though we know some of them are.) It takes time plus shifts in shared opinions, which cause some taxa to swing back and forth, recognized and then lumped as broad vs. narrow species concepts go in and out of fashion.

Keep in mind all the species that haven’t been split! The great majority of North American birds, for example, though many have been shifted around among genera. Many common and widespread plants. We’re not just tunneling down a one-way need to split!

At least most of us aren’t. As discussed before, taxa that mix asexual and sexual reproduction, like dandelions, produce patterns of variation that just can’t meet human needs for labeling; one strategy used is extreme splitting, though many taxonomists don’t accept it. In a very few taxa, people pursuing recreational taxonomy are doing extreme splitting and driving their colleagues crazy.

And be aware that reasonable splits of conspicuously different taxa will be coming, too. I can think off hand of two taxa of Lomatium I had to lump with what I consider a different species just because there wasn’t any other published name to apply to them, but you’d have no trouble distinguishing them from iNaturalist photos. Of course, some recent and soon-to-come taxonomic changes in Lomatium are be more cryptic but take some comfort in the fact that my coauthors and I did lump two taxa that we didn’t think were different.

Enough rambling. Time to go process tomatoes from my garden.


well for my part at least, i am not arguing that the splits don’t have reasons behind them, nor that they aren’t monophylletic or anything like that. What i am arguing is that for most of these it’s absurd to elevate them to species level. There’s no hard science reason they should be species, and no agreed on consistent definition of species, despite what some taxonomists may claim. Nearly all recent splits in plants at least should be subspecies or varieties.


If taken to extremes, the phylogenetic species concept creates more problems than it was supposed to solve. The phylogenetic species concept, in which any “diagnosable,” group* that is monophyletic = a species, makes people who take it very seriously tend to oversplit. In sexually reproducing species, any groups that are geographically isolated can easily develop some consistent differences, if only at the DNA level (especially in junk DNA if some of the populations are small). In asexual species, we may want to treat extensive clones as different taxa, though they could just as reasonably be thought of as different individuals.

  • diagnosable = consistent and detectable in some way

However, most taxonomists, especially older = more experienced taxonomists, try to balance human needs with their application of species concepts. After all, species concepts are about giving humans the words needed to discuss existing, real variation. Some, especially young and idealistic gene-jock taxonomists, could use a little more practical experience. The balance swings back and forth, but the time period of this swing is generational so we can get tired of waiting for it to return. (I get very tired of taxa I’ve seen split and lumped and split and . . . in my lifetime.)


Totally agree. Part of the problem might be that one probably gets more recognition for naming a new species, elevating a subspecies, or resurrecting an old name than one would for lumping two or more taxa. Splitting is more exciting. Not saying that’s the driver of many splits but it can be an influence in decision making.


Yes, it can.

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David Hillis has an interesting article on oversplitting and species delimitation in herpetology. I like his Figure 1 flowchart in the article.