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Classification: Why and How?

Paul Grobstein's picture

Senior Seminar in Biology and Society

September 8, 2009

From Shakespeare's Romeo and Juliet, 1594:

      'Tis but thy name that is my enemy;
      Thou art thyself, though not a Montague.
      What's Montague? it is nor hand, nor foot,
      Nor arm, nor face, nor any other part
      Belonging to a man. O, be some other name!
      What's in a name? that which we call a rose
      By any other name would smell as sweet;
      So Romeo would, were he not Romeo call'd,
      Retain that dear perfection which he owes
      Without that title. Romeo, doff thy name,
      And for that name which is no part of thee
      Take all myself.

Would a rose by any other name actually smell as sweet?  Was Montague no part of Romeo?  Biology, like many other sciences, has its roots in classification, in the naming of things, in categorization.  Do we still need categorization?  Is there a right way to categorize?  Some relevant recent materials for discussion ....

Paul Grobstein's picture

The breadth of the classification problem

For some impacts of our conversation, and some further perspectives on it, see

ttruong's picture

The first name is arbitrary

I think that the initial process of classification is abitrary. For example, in forming phylogenetic trees we must assign more salience to certain phenotypic characters than others when we are determining which species are more related to each other. Our decision on which shared trait is more important and more correlated with the relatedness of certain species can sometimes be arbitray. In the same way, it is arbitrary for us to decide which characteristics carry enough importance that when objects express all of them together, we group them together with a name.

However, once the initial arbitrary step is completed and understood among a group, it is no longer arbitrary to give such objects other names. Since the name that was assigned to those objects have already attain connotations and assumptions from people from having been grouped under that name in the first place.

Also, once an established label with understood properties is given to an object, the object acquires the properties that comes with the label. Therefore, classification is a quick and efficient system that we humans have devise so that our brain can instantly assign properties of objects by simply learning the name of them.


jrlewis's picture

alternatives exlcude

A name is a definition, recounting the properties of specific concepts or things.  The act of ascribing a name to a concept or thing makes it determinate.  To say what something is, is to also to say what it isn’t.  So every “arbitrary” decision in the process of nomenclature that we make, has consequences.  The system of nomenclature we construct constricts the possible stories we can tell about the named concepts or things. 

RachelBrady's picture

The Functions and Limitations

The Functions and Limitations of Classification

I mentioned in class that I had found a relivant article to our discussion that I would post. I'm really not expecting everyone to read the whole thing (it's a bit lengthy), but I wanted to point out the argument in the essay which we didn't spend much time discussing in class.

He explains the origin and significance of classification as a "the invention by man of ways in which events and things can be grouped, for the sole purpose of increasing his ability to deal with the events and things." This is important because, using these groups, man then has "disciminative capacities far beyond his ability to remember the details."

He does not ignore the issues/implications and limitations of classification that we discussed. Instead, he redefines the problem as a miss-use of the system in applications outside of which it was designed.

"It is hardly a failure of a radio set to be unable to produce visual images - it was designed to produce only auditory reactions."

It was very thought provoking, especially because it is not a common stance taken (at least in my experience). Actually, in my experience, people are usually angered at the idea of being classified in anyway, stating that the associated are limiting, and simplify the human experience. At the same time there are people who use classification to there advantage, like using one's race as an edge to get into college.

Now I realize I've diverged quite a bit from my original point, but I am interested in hearing what the rest of you thought of this essay.

Paul Grobstein's picture

classification: uses and caveats

I think its a very interesting essay, even more so given that is was written in 1959 and directed at a quite narrow issue and audience, classification of the invertebrates by professional systematic biologists.  Thanks for bringing it to our attention.  What's worth thinking about, among other things, is the applicability of the concerns in a whole series of both biological and wider contexts, including not only health and social policy but our own inclinations to categorize or not categorize both others and ourselves.  Some apt points, in addition to those Rachel mentions about why classification is useful and the need to avoid "mis-use" ...

"It has been evident for a long time that classification of animals has been plagued by a series of hypotheses that attained such a firm hold that no one even dared to speak about the possibility that they might be faulty."

"all of us accept things which we cannot justify and claim there is a basis for ideas for which we can produce no real basis.  This is the nature of the strange organ we call the human mind."

"Classification is many things to different people ... There is a variety of definitions of what a natural classification is."

"Classification is ... not the recognition of something that exists in nature, for nature is not classified.  It is the invention by man ... "

"The general purpose of all classification ... is to bring order to a mass of data too great to be fully understood separately. But every classification will by its very nature serve only the purpose for which it is designed ... inference of unknowns from knowns is the real purpose of most classification."  (PG: Perhaps also the recognition of unknowns and questions following from those?)

"A recent zoology textbook tells us that taxonomy emphasizes the differences between organisms.  This is true only if we are looking at it after the work of classifying is done ... real classiciation always employs similarities, and the differences appear mostly as a by-product."

"In the constant effort to simplify biology for teaching purposes, we have submerged the evidence that variety is the most obvious characteristic of the animal kingdom."

An electron is an electron is an electron.  But a rose ... differs from all other roses.  And a Montague or a human or an elephant or an E. coli differs from all other instantiations of those things.  Yes, there are similarities but in focusing on those we obscure the differences.  Maybe the most important thing to teach about biology is the importance not only of similarities but also of differences? 

jrlewis's picture

The rate of change of an intellectual reaction?

Or how long does it take for scientists and general society to accept new discoveries, reclassifications, and theories?  The amount of time varies significantly.  I think that Thomas Kuhn’s characterization of the history and philosophy of science might offer some insight.  He differentiates between two modes of scientific progress normal science and revolutionary science.  Normal science is puzzle solving guided by a paradigm, story, or theory.  New observations and summaries of observations are added to the paradigm.  Revolutionary science occurs when one paradigm replaces another.  There are many reasons why one paradigm may supplant another.  The new paradigm might able to summarize the observations more simply, or offer different research opportunities, or answer questions that previous paradigm was unable to address.  I would like to argue that a change in nomenclature implies a change in theory.  Naming is a method of summarizing information; it is a component of a paradigm.  Therefore, Pluto’s reclassification is a small paradigm change, an example of revolutionary science.  The controversy described in the above articles are merely indications that the revolution is not finished. 

ttruong's picture

Different name, same revolution.


I really like these two descriptions of the progress of science. I think that scientific progress is definitely a combination of revoluntionary leaps and accumlation of new observations and summaries (normal science). Take Darwin's ideas of evolution for example. His ideas of descent, with modifications, from common ancestors was a revolutionary leap, being formulated when people were still very deeply indoctrinated in ideas of special creationism. However, his ideas were incomplete with gaps easily targeted for attacks from non-believers. Only with the rediscovery of Mendel's research of hereditary particles (genes) did Darwin's theory become more coherent. Further research of fossils and carbon-dating, Watson-Crick's discovery of the structure of DNA, and advances in genetic analysis continue to add evidence to the theory of evolution. After Darwin's first revolutionary shift, normal science entered to fill in the missing pieces to form a more coherent story. The  two modes work together push science further along.

There are times when names that are given at the time of the revolutionary leap, when the story was still not so coherent, need to be altered once the story has been supplemented with further research. The name change is not necessarily indicative of another revoluntionary change; it is indicative that a more advanced understanding (that's still within the same paradigm)of the concept or object has been established.

RachelBrady's picture

I'm not very familiar with

I'm not very familiar with Kuhn's theory, but if revolutionary science occurs when one paradigm replaces another, is it possible, within this science to have a confrontation of scientific theories, and if not how would one account for their occurance in science? For example in the field of human evolution, there is much dispute over the classification of species and how they relate to each other. These theories oppose each other, co-existing because they can neither be proved or disproved.

jrlewis's picture

My best guess is that Kuhn

My best guess is that Kuhn would consider the controversy you describe as a sign of an impending revolution in the field of human science.  Not that it will suddenly become possible to prove or disprove one of the theories, rather that new observations and more creative ways of interpreting them will lead to the temporary adoption of a particular theory. 

One of the more ambiguous elements of Kuhn's theory is the span of time over which it is applicable.  Revolutions don't occur in a day, possibly not even an easily defined period of time.  Who will measure when the last person is converted to the new paradigm?

Lisa B.'s picture

What about the textbook industry?


What about the textbook industry? This was my first thought after remembering that Pluto is no longer a planet. The NY Times did not address this concern in “Vote Makes It Official” when the article casually mentions, “Throw away the place mats. Redraw the classroom charts. Take a pair of scissors to the solar system mobile.” The $4 billion ( elementary and secondary textbook industry probably celebrated the news of Pluto’s downgraded planetary status. Although I easily accepted the statements made by scientists, at the International Astronomical Union, that Pluto is only a mass of ice, would school boards share my ease? The California public school system alone has to budget for over $500 million ( in textbooks, but new elementary and secondary science texts would dramatically increase their expenses. According to the Atlantic many teachers were not “waiting for textbooks to make the jump.” “When Is a Planet Not a Planet?” said that textbooks, together with teachers, have the power to influence the number of children who grow up thinking that Pluto is an icy mass. “If enough of them become astronomers, the IAU will follow.”  


Paul Grobstein's picture

classification and textbooks

Maybe this is another reason to get rid of textbooks?  See Textbooks and Introductory Science Education