The Structure of the Developmental Paragraph: Part II (Coherence)

I tell my students that the sentences in a paragraph must hook together like links in a chain, rather than merely being strung together like beads. In other words, the elements of the paragraph, like the elements of the essay as a whole, must be logically structured.

When I was a student, two different words were used to describe the logical structure of the whole essay and the logical structure of the paragraph: coherence for the essay; cohesion for the paragraph. But since both words have the same etymology and the same meaning, I see no reason to use two words where one will do. Therefore, I will use only the word coherence to describe the logical linking of ideas, whether from paragraph to paragraph at the level of the essay as a whole, or from sentence to sentence within the paragraph unit.

Both coherence and cohesion mean to stick together or hold together, to be logically consistent, to be well-integrated and systematically unified. But coherence
has a distinct advantage: it is the word we normally use in everyday speech to refer to logical consistency and to things that make sense. We might well call an utterance or an argument incoherent, but who would ever call one
incohesive?

First, I direct them to identify the main point of the paragraph and to underline the topic sentence that embodies this main point. It is important to start by asking what the main point of the paragraph is, not what its topic sentence is. Only after the student is fairly certain about what point the paragraph is trying to make and develop is he ready to decide which sentence best embodies that point.

A very skilled writer can fool around with a withheld or implied topic sentence, but most writers are better off if each developmental paragraph has a clear topic sentence, and if each topic sentence appears at or near the beginning of the paragraph it governs. Anything less precise is likely to allow the writer to get off topic or to lose direction in his paragraph--and if the writer gets lost or sidetracked, then the reader will also get lost.

After the student finds the topic sentence of a paragraph, I ask him to look at the last point made in the paragraph, to decide whether it is even possible to "get there from here." In other words, if his topic sentence says, for example, "Fraternities are notorious for hazing their pledges," and the last sentence of the paragraph says, "But fraternities do not encourage their members to tolerate diversity, much less to seek it out," then we have a coherence problem.

Obviously there is no way for "But fraternities do not encourage their members to tolerate diversity, much less to seek it out" to be considered a developmental aspect of the idea that fraternities are notorious for hazing their pledges. It is a different topic altogether, and it occupies the same level of generality as the idea that fraternities haze pledges.

Both topics are points under a general heading that might be labeled "What's Wrong with Fraternities." One problem is the hazing of pledges, and another problem is the lack of tolerance for diversity. Each point needs its own paragraph of development (or paragraph bloc,* if the essay is very long and detailed), as would other points of the same level of generality.

Some such points might be "Fraternities often encourage alcohol abuse," "Fraternities encourage students to remain dependent at a time in their lives when they should be learning to be independent," and "Fraternities promote 'groupthink' over individuality."

The order of the points would also need to be considered. An essay structure that moved from alcohol abuse, to hazing, to dependency, to group mentality, to intolerance for diversity would seem logical, and the transitions from one paragraph to the next would be smooth and natural.

But if the order were scrambled, the natural transitions would be lost, because the logical relationships among the parts would be obscured. Imagine the essay organized thus: dependency, lack of tolerance for diversity, alcohol abuse, group mentality, hazing. It doesn't work, does it?

The same thing is true within the individual paragraph. The fact that all sentences in a paragraph are on the same topic does not necessarily mean that the paragraph will be coherent. The sentences still have to be arranged in a logical order, and the connections from one sentence to the next have to be made clear by means of transitional markers, words or phrases that establish a sentence's logical relationship with the sentence that precedes it or the sentence that follows it.

As I was writing this article, I was also reading a book by Jared Diamond entitled Guns, Germs, and Steel (N.Y.: W. W. Norton & Co., 1999). By a most surprising coincidence, as the book is actually very well written, I found in it some examples of the kinds of paragraphing problems that can be spotted by doing the sort of structural analysis I advocate.

In the two paragraphs that follow, Diamond is describing the effect that latitude has on the germination, growth, and disease resistance of plants. Before you read my analysis of the paragraphs' structure, try analyzing the passage yourself as I have described and see if you come up with something similar to my critique.

But the germination, growth, and disease resistance of plants are adapted precisely to those features of climate. Seasonal changes of day length, temperature, and rainfall constitute signals that stimulate seeds to germinate, seedlings to grow, and mature plants to develop flowers, seeds, and fruit. Each plant population becomes genetically programmed, through natural selection, to respond appropriately to signals of the seasonal regime under which it has evolved. Those regimes vary greatly with latitude. For example, day length is constant throughout the year at the equator, but at temperate latitudes it increases as the months advance from the winter solstice to the summer solstice, and then it declines again through the next half of the year. The growing season--that is, the months with temperatures and day-lengths suitable for plant growth--is shortest at high latitudes and longest toward the equator. Plants are also adapted to the diseases prevalent at their latitude.

Woe betide the plant whose genetic program is mismatched to the latitude of the field in which it is planted! Imagine a Canadian farmer foolish enough to plant a race of corn adapted to growing farther south, in Mexico. The unfortunate corn plant, following its Mexico-adapted genetic program, would prepare to thrust up its shoots in March, only to find itself still buried under 10 feet of snow. Should the plant become genetically reprogrammed so as to germinate at a time more appropriate to Canada--say, late June--the plant would still be in trouble for other reasons, for its genes would be telling it to grow at a leisurely rate, sufficient only to bring it to maturity in five months. That's a perfectly safe strategy in Mexico's mild climate, but in Canada a disastrous one that would guarantee the plant's being killed by autumn frosts before it had produced any mature corn cobs. The plant would also lack genes for resistance to diseases of northern climates, while carrying useless genes for resistance to diseases of southern climates. All those features make low-latitude plants poorly adapted to high-latitude conditions, and vice versa. As a consequence, most Fertile Crescent crops grow well in France and Japan but poorly at the equator. (184)

Now, the last sentence of the second paragraph only seems out of place. Both paragraphs are actually part of a three-paragraph bloc that develops the point that the food crops first domesticated in the Fertile Crescent spread rapidly across Eurasia because that continent has an east-west axis, so that much of it lies within the same latitude. Thus, crops evolved in one part of Eurasia are well-adapted to grow in many other parts of Eurasia.

Notice that the first sentence of the fist paragraph serves as a general topic sentence for the two-paragraph unit: But the germination, growth, and disease resistance of plants are adapted precisely to those features of climate. The entire rest of that paragraph, except for the last sentence, develops the idea that latitude affects germination and growth rates in plants. Then, suddenly, the last sentence of the paragraph introduces a new topic: Plants are also adapted to the diseases prevalent at their latitude.

Not only does Diamond introduce a completely new topic in a paragraph devoted to plant germination and growth, but he then fails to develop it at all, returning instead to the different germination and growth patterns that evolve at different latitudes. Then, at the end of that second paragraph about germination and growth patterns, he once again mentions that plants are adapted to the diseases found at their native latitudes.

A coherent structuring of these two paragraphs would leave the last sentence off of the first paragraph and the third-to-last sentence off of the second paragraph. Then, both paragraphs would constitute an extended development of the first two inter-related parts of the paragraph bloc's topic sentence: But the germination, growth, and disease resistance of plants are adapted precisely to those features of climate.

That the first two elements, plant germination and plant growth, belong together is clearly demonstrated in the actual development of the two paragraphs. The third element of this topic sentence, however, is too different from the first two, so it needs its own paragraph of development. Instead, plant disease is thrown in suddenly and incongruously at the end of each paragraph, and then dropped with no further development.

Besides being a violation of coherence, this clumsy arrangement also violates the principles of proportion and
balance (or symmetry), which are aspects of both logic and aesthetics. The principle of proportion requires that a point be developed according to its significance, so that less significant points are developed only slightly, if at all, and more significant points are developed in greater depth and detail. Balance (symmetry) requires that points of approximately equal significance should be developed to approximately equivalent depth and degree.

Obviously, plant disease is of the same order of generality and significance as plant germination and growth, and it should also have its own paragraph of development. All three are subpoints of the main idea of the three-paragraph bloc, that the food crops first domesticated in the Fertile Crescent spread rapidly across Eurasia because that continent has an east-west axis, so that much of it lies within the same latitude.

How did you do in your analysis of the structure of these two paragraphs? Did you notice the breakdown in coherence and the lack of proportion and balance? Try this exercise on the paragraphs of your own discursive writing, or, if you are a teacher or a homeschooling parent, use the same method to analyze the structure of your students' or children's paragraphs.

5) Are there any sentences that do not develop the topic sentence of the paragraph? If so, are they merely extraneous matter, or are they relevant points that should be part of the development of another paragraph, or even points of the same order of generality as the topic sentence, so that they should get their own paragraph of development?