Field of Science

Is Taxonomy a Science?

A couple of days ago, I referred to the point that the dividing line between the sciences and the humanities is not particularly clear, and there are some forms of research that do not fall clearly on one side of that divide. Taxonomy, the practice of classifying and characterising organisms, has been described as one such practice. So it is worth asking - is taxonomy a science?

First, of course, one needs to establish what exactly science is, a topic that has taken up entire volumes. One of the main characteristics of science, though, is the use of the scientific method. Hopefully, you would have had this explained to you in high school, probably as a scientist constructs a hypothesis about something, devises an experiment to test that hypothesis, then finds whether the results of the experiment support the initial hypothesis, refining the hypothesis as needs be (for instance, a hypothesis that hydrogen and oxygen combine to form water may be tested by burning hydrogen in oxygen and finding whether water is produced). Lather. Rinse. Repeat. For many branches of science, however, this is not really an option. In studies such as phylogeny, astronomy or geology, we generally can't directly experiment on our subjects as such. To use Stephen Jay Gould's metaphor, we can't rewind the tape of time, fiddle with the parameters, and see how things could have turned out. Nevertheless (contrary to what some have said), the scientific method is still applicable to these studies, but instead of directly experimenting on the object of study, the method goes somewhat more like this - the researcher will collect a body of observations, construct a hypothesis that explains the observations, then collect further observations and see whether the initial hypothesis still explains the available body of observations (for instance, observations that koalas are only ever seen eating eucalyptus leaves leads to the hypothesis that they have a diet solely composed of such leaves, which may then be tested by continued observations on koala diet). These two methods may be referred to as the experimental or "hard" scientific method and the observational or "soft" scientific method. Needless to say, the two methods blend into each other (is a developmental geneticist staining embryos to find where a certain gene product is expressed conducting experiments or observations?), and are not exclusive.

As a discipline, taxonomy can actually be divided into two distinct but interleaving components - systematics is the identification of relationships between organisms, while nomenclature is the process of determining what the various groupings of organisms identified by systematics should be called. Nomenclature, it should be stressed, is not a scientific process. The name Homo sapiens is not science, just as the equation "E = mc2" is not science. The process by which Einstein established that energy was equivalent to mass multiplied by the speed of light squared was science, but there was no inherent reason why the resulting equation had to be expressed in the format used. Had Einstein used a completely different set of symbols (say, "۞☺۝۩"), it could have still meant exactly the same thing. Similarly, the name given to a taxon is simply the linguistic tag used to identify that taxon, not the taxon itself. Once a particular tag has been established for a particular taxon, it is in every researcher's best interest to continue using that tag rather than inventing a completely new tag every time that taxon is referred to but this is a question of communication, not of science.

Systematics, on the other hand, is a scientific process - most of the time. Imagine I have a collection of unsorted arachnid specimens in front of me (which, as it happens, I pretty much do). I divide these specimens into smaller clusters whose components are morphologically more similar to each other than to specimens in other clusters. For the sake of argument, say I decide that these clusters represent separate species. These species are then able to be tested. I may look at further specimens to see if the boundaries between my various species remain constant, or whether there are specimens that blur the boundaries between clusters. I may use alternative data sources, such as genetics or biogeography, to see if my clusters remain consistent across methods. But while my initial division may be able to be tested scientifically, did it represent a scientific process itself? You might argue that it did not - that it involved a purely subjective judgement about similarities between specimens on my part. What about species that have been erected on the basis of single specimens, and so cannot be said to have been properly tested? I might reply that my own experience, and what I've learnt from the experience of others*, may have taught me a great deal about what kind of characters are likely to be reliable in distinguishing taxa. But is this a scientific progress, or an application of learning? What is the difference?

*In the past I've complained about the errors of past workers such as Carl-Friedrich Roewer complicating the taxonomy of harvestmen that I work on. At the same time, it cannot be stressed enough that I can only criticise the work of my predecessors because I have the published experience of later workers to draw on - Hickman, Martens, Staręga, the Goodnights, even Roewer himself. This is what Isaac Newton was referring to when he noted that "If I have seen farther it is by standing on the shoulders of giants".

In the end, I have to fall back on a quote from Bonde (1977) that I've used before: "An important aspect of any species definition whether in neontology or palaeontology is that any statement that particular individuals (or fragmentary specimens) belong to a certain species is an hypothesis (not a fact)". In my initial establishment of a species (especially if said species is only based on a single or very few specimens) I am essentially proposing a hypothesis that may be tested at a later date. The hypothesis itself may arguably not be science, but the scrutiny it will later be held up to almost certainly will be.


Bonde N. 1977. Cladistic classification as applied to vertebrates. In Major Patterns in Vertebrate Evolution (M. K. Hecht, P. C. Goody, & B. M. Hecht, eds.) pp. 741-804. Plenum Press: New York.


  1. Put another way, the coining and defining of names is not a science, but the application of definitions can (and arguably should) be.

    (I should have more to say on this later this year....)

  2. Careful now, Mike, don't go putting PhyloCode in my mouth :-P

  3. Objective definitions existed before the PhyloCode. (I'm referring to something else, anyway.)

  4. Nice post!

    I think that systematics is a science when species are included into a most global framework (i.e. a classification). The species separation process as you describe it, is a very technical work (and absolutely necessary, if you want to put species in a classification!!).

    Species description (and its corresponding morphological/anatomical analyses) is just the starting point, they are raw data (using your example, it is not only produce water by mixing oxygen and hydrogen, but learning why, or how this thing happens!).

    As you observe, the acquisition of such acknowledge is vital, and the most beauty part, is that although our understanding of classifications might change across time, if well doing, that original descriptions will continue to provide relevant information!

  5. I think the current idea that science is only experimental science is wrong. Accurate observation of natural phenomena is also science. The defining character of science is integrity of observation and measurement. Linnaeus was being a scientist when he wrote "Systema Naturae", and so was Darwin when he worked on barnacles.

  6. Well, description is certainly part of science, but nomenclature isn't. Systema Naturae does have science in it, but I think the reason it's such an important work is that it emphasized the importance of nomenclature as a discipline in the service of science, and gave biological nomenclature a starting point.

  7. Accurate observation of natural phenomena is also science.

    I would say, not quite. Accurate observation of natural phenomena is natural history, not science. As Salva referred to, it doesn't become "science" until said observations are incorporated into some sort of explanatory framework that tries to find the underlying processes behind the observations.

    However, I also think that the downgrading of people's regard for "natural history" is also pretty unfortunate. While natural history and nomenclature may not themselves be science, science is entirely dependent on good natural history and nomenclature in order to function. The Systema Naturae is actually a pretty good example. For the most part, the Systema Naturae is largely an index to prior publications. The compilation of an index may not have constituted a scientific work in itself, but it would have been a vital tool in the construction of many a scientific work afterwards.

  8. There's only one Science, and anything that helps is part of it. A key criterion is whether anybody is interested in correcting mistakes.

    Much of what passes for modern astronomy, particle physics, and particularly cosmology isn't science at all.

  9. "Accurate observation of natural phenomena is natural history, not science." _____ And Natural History, which is the accurate documentation of Nature, is a part of science. This covers not only White discovering the different species of leaf warblers, but also large scale sky surveys such as the Sloan Digital Sky Survey (SDSS). I bet the SDSS is paid for out of a science budget. _______ You don't have to be formally generating and testing hypotheses to be doing science. What is crucial is to be pepared to submit to peer review and accept corrections, as opposed to claiming divine authority for your statements.

  10. Hypothesis-testing is one portion of the scientific method. Experimental work is one portion of the scientific method. Read:

    Brandon, RN, Does biology have laws? The experimental evidence. PSA 1996, vol. 2, 444--457.

    I summed it up in the second half of this post.

  11. Pete Saussy
    i'm going to follow your comments, what i can follow! I'm not a scientist just a semi-pro lexicographer who tried to find a taxonomy of metaphors. lots of data but only fossils of greek and latin. any suggestions for some basic rules?
    not on metaphors but disambiguiation [sp?]"drawing lines"?

  12. Taxonomy can only be considered scientific at the species level. People argue about the definition of species, but at least they have definitions to argue about, and usually they agree in the end that X and Y are actually "species."

    But what constitutes a genus or family? Nobody has any idea. Nobody even tries to define them. They are totally arbitrary levels of organization. It is obvious, for example, that birds are given separate genera much more freely than trees or frogs. Systematics can study the relationships of organisms, and test hypotheses such as "is organism B closer in relation to organism D or G?" But the names chosen to apply to those organisms is not a question of science. Introducing science to a process does not make the process science, just as introducing a tennis ball to a football game does not make the game tennis.

    Taxonomy involves science, and it serves science, but it is not a science.

  13. Taxonomy, the practice of dividing organisms into sets (taxa), may or may not be a science. If based on opinion, it's not; if based on hypotheses (e.g., phylogenetic hypotheses), it is.

    Nomenclature, on the other hand, is never a science. (That I can think of, anyway.)

  14. Came across this article after google search on "how is taxonomy scientific?"

    Must say, this article doesn't persuade me to believe that it is. For sure, I learned a few things, but not anything that seems new exactly. It is a nice article, and helps understand a few things, but I think it falls short in explaining how systematics is scientific process.

    Here is where I identify the argument becoming suspicious: "say I decide that these clusters represent separate species. These species are then able to be tested."

    The "species" are able to be tested regardless of the distinctions made by the observer. I don't know if that can be over-emphasized, but I feel it needs to be stated, and made clear, otherwise science becomes incredibly vague in definition and limited in scope. Which it has, and unnecessarily continues to be.

    My bias: Science attempts to be all things (philosophy) to all things studied. That is a bold attempt, and I actually think even worthwhile, but NOT if it is leading us (as a species) to proclaim things that are simply NOT OBSERVABLE. In other words, I'm asked to agree to scientific taxonomy, not only because it is useful for further study, but because it is "the right thing to do." As if, my own (or any other) systematics could deem me as non-sensible and furthermore, non-scientific. Hence, dogma abounds and makes something into science (and scientific process) that is just not defensible, except by fanaticism. It becomes defense based on emotion, rather than Reason.

    Science is knowledge and scientific process is the growth of (specific) knowledge. If we can leave it at that, we can likely get along as a species and do science a service. But this classification BS, is mucking up the waters and placing 'modern science' in domain of fanaticism' and dogma. While some scientific types might disagree with that assessment, all tests and observations I've made in last 10 years can, rather easily, validate this.


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