Classification and Partition

Classification is the orderly, systematic arrangement of related things in accordance with a governing principle or basis. The classifier notes the structural and functional relationships among things that constitute a class. In recording this relationships, the classifier employs certain conventional terms. Acquaintance with these convenient terms will make the rest easy to follow.

Genus and Species

A genus is a class; a species is a subdivision within a class. If technical subjects are the genus, then, TC, Chemistry, and Calculus are species; if calculus is the genus, then differential, integral, and infinitesimal are species. These two terms are very commonly used, but many others can be used if a more complex classification is needed.
The animal life gives as much as 21 categories from subspecies, species, subgenus, genus, subtribe, tribe, subfamily, family, superfamily, infraorder, suborder, order, superorder, chort, infraclass, subclass, class, superclass, subphylum, phylum, and finally kingdom, the broadest group of all. Elaborate classifications are designed to tell all that is known about the structural and functional relationships among the individuals of the classification.

Classification

This term has a loose popular meaning and a more precise technical one. Popularly, classification is almost any act of noting relationships. Technically, classification is the act of locating a specimen of all the different kinds of objects that posses a given characteristic or characteristics. Initially, classification must begin with the recognition that different things posses similar characteristics.

Logical Division

The division of the collected data which is already classified is called logical division. In report writing it is usually logical division, not classification that is concerned with; nevertheless, the term "classification" is the one most likely used even where "logical division" is technically correct.
One might write, "Engines can in general be classified as full diesel, modified diesel, and gas." This is logical division simply because it is a division into three groups of information already known. But it is likely that an engineer or a technician would say "classified" rather than "logically divided" - to judge from our own acquaintance of technical literature. For that reason and for convenience in general, the term "classification" to mean either logical division or classification is used. The chief concern will focus in logical division, since the report writer is almost concerned with arranging a collection of facts or ideas, in order to discuss them in return, rather than hunting down new species. After all, the hunting will necessarily have been done before the writing starts.
If we are going to use the term "classification" you may wonder why we bothered to distinguish between it and logical division at all. The reason is twofold: first, just to get down all the facts; and second, to avoid confusion when we go to the next term on our list.

Partition

Partitioning is the act of dividing a unit into its components. The parts do not have necessarily had anything in common beyond the fact that they belong to the same unit. A hammer may be partitioned into head and handle. Hammers may be logically divided according to physical characteristics of their heads as claw, ball peen, and so forth. Classification, or logical division, always deals with several (at least two) units. Partition deals with the parts of only one unit. A hammer is a single unit. A hammer head without a handle is not a hammer. The head and the handle are parts of a single unit. You have probably become familiar with a variety of partitioning in a chemistry course when you determine the components of a chemical compound.

Basis

At the beginning of this subject we have classified engines. How should we classify engines? On the bais of power, use, the kind of fuel they burn, or where the combustion occurs? The manufacturer who is looking for a gas engine to use in a power lawn mower scheduled for production would not thank you for a classification of small engines according to the place where the combustion occurs. What basis would be helpful? Power? Weight? Cost?
These terms, then, are the ones to remember; genus and species, classification, logical division, partition, and basis.

When is Classification a useful expository Technique?

The foregoing discussion has suggested why classification is a useful technique of exposition: it permits a clear, systematic presentation of facts. When to use this technique depends on whether a writer is dealing with classifiable subject matter and whether his or her writing can be made more effective by means of the technique.
To get an idea of when this technique is useful, let's consider a specific writing problem. Let's suppose that a report is needed on kinds of vat dyes (capacitors for elex, wires for electrical, drill bit for mech). And let's suppose further that the readers of this report will need to be given an understanding of the properties of these dyes so they can use the dyes effectively. It would be possible to discuss each of the 40 or 50 dyes in turn, of course, giving all the pertinent information about dye No. 1, dye No. 2, and so forth. But it is hard for any reader to keep in mind 40 or 50 individual sets of characteristics. A better possibility is to classify all these dyes into groups having characteristics in common. It would be much easier for readers of the report about these dyes to remember the characteristics of a group, and to relate an individual dye to a group, that it would be to memorize the behavior of all the dyes individually.
Classification, then, is useful when you have a number of like things to discuss, among which there are points of similarity and difference which is important for the reader to understand. Obviously, however, the relationship among the things classified must be a significant one.
Suggestions to follow in presenting a classification in using classification as an effective way of presenting related facts, it is helpful to follow a number of "rules," all of which are simply commonsense suggestions for clarity and meaningfulness.

1. 1. Make clear what is being classified. This needs the definition of the subject if there is a question as to whether the reader will be familiar with it. Grouping the related members of a class will mean little to a reader who does not know what you are talking about in the first place.

2. 2. Choose (and state) a significant, useful basis, or guiding principle, for the classification. The basis of classification governs the groupings of members of a class. A classification of drafting pencils according to the color they are painted would be of no value at all, perhaps to the aesthete who prefers a magenta to a pink. The bais should point to a fundamental distinction among the members of a class.

3. 3. Limit yourself to one basis at a time in listing members of a class. Improper choice of terms is not so obvious an error in this area of concern. An author, illogically listing fuels as "solid, gaseous, and automotive," may actually have been thinking correctly of "solid, gaseous, and liquid," but no matter what this author was thinking, the term "automotive" was illogical. Still another practice to avoid is the listing of a specific variety instead of a proper species name, as listing fuels as gas, liquid, and coal (instead of "solid").

4. Name all species according to a given basis. Tell the readers what the limitations are upon the classification you are presenting, so that they will not expect more that it is your intention to give. Classification of steels according to method of manufacture, for instance, would not need to contain mention of obsolete methods. Limiting a classification means making clear what is being classified and for what purpose. Thus, a classification of steels might begin: "Steels commonly in use today in the Philippines are made by . . . " The rest of the statement would name the methods of production. In this statement three limitations are made: steels made by uncommon methods of production are neglected, steels made by the methods of the past are omitted, and finally steels made in other parts of the world are ignored.

5. Make sure that each species is separate and distinct - that there is no overlapping. The species of a classification must be mutually exclusive. Classification of reports as research, information, investigation, recommendation, and so on illustrates this error, for it is obvious that not one of these necessarily excludes the others; that is, a research report may most certainly be an investigation report or a recommendation report. To guard against this error, examine the listing of species you have made and ask yourself whether species A can be substituted for species B or C, or for any part of B or C.

6. Help your reader understand the distinction between species. Discuss each species, giving a definition, description, or illustration of each - perhaps all three. In a discussion of steels it might be desirable, according to a basis of the number of alloy elements, to list binary, ternary, and quaternary alloys. It would then be natural to explain, unless it was certain the intended readers already understood, what each of these terms means, what alloy elements are used, and what special qualities each one contributed to the steel. What we are talking about here is not peculiar to classification writing; it is the same old story of developing your facts and ideas sufficiently so that your reader can thoroughly understand you.

7. Make certain that in a subclassification you discuss characteristics peculiar to that one subclassifiaction only. It is the same as clarifying the subject but in this case you will point something significant about this particular kind and not something characteristic of any kind.

In the process of subdividing a subject, a point is reached at which no further subdivision is possible. At this point, one is dealing with varieties of a species.

A Note on Partition

Earlier we defined the term "partition"; now we will comment briefly on the use of partition in exposition. Classification, as we have seen, is a method of analysis ( and exposition) that deals with plural subjects. You can classify houses, for instance, by considering them from the point of view of architectural style, principal material of construction, number of rooms, and so on. But you cannot classify a house except in the sense of putting it into its proper place in a classification that deals with houses. You can analyze a particular house, however, by naming and discussing its parts: foundation, floors, walls, and so on. This analytical treatment of a single thing (idea, mechanism, situation, substance, function) is called "partition," or simply "analysis." As you know, it is a familiar and useful way of dealing with a subject. The seven classification rules that were discussed also apply to partitioning.

You don't need to be urged to break down a subject for purposes of discussion. You would do it anyway, since it is a natural, almost inevitable, method of procedure. After all, a writer is forced into subdividing subject matter for discussion because of the impossibility of discussing a number of things simultaneously. What is emphasized is that logical and effective principles in carrying out such divisions should be followed.

(d) Methods of attachment
(e) Material
(f) Finish
b, c, etc.- same as "a"
B, C, etc. - same as "A"