Tell David, he needs to discuss types of old-topic references including the near and the distant, the synonym and antonym types, multiple old topics, and the previous topic summarizer.
Revising a draft for its organization and coherence is one of the most important things you can do to improve that document—far more so than correcting grammar, usage, and punctuation errors. However, you can't get very far in this process unless you can identify topics and subtopics at various levels of a document. Successfully identifying topics and subtopics requires some study and practice which this chapter provides.
At its simplest, identifying the topic of a paragraph is a matter of picking out a keyword that conspicuously occurs multiple times. Think of the occurrences of those keywords as a topic string. There seem to be two basic types of topic strings: continuous topic srings and shifting topic strings.
Here's an example of a continuous topic string, one in which the topic word is roughly the same each occurrence:
| Mars is the fourth planet from the Sun in our solar system and is named after Mars, the Roman god of war. Mars is also known as the "Red Planet" due to its reddish appearance when seen from Earth. The prefix areo-, from the Greek god of war, Ares, refers to Mars in the same way geo- refers to Earth. Mars has two moons, Phobos and Deimos, which are small and oddly-shaped. |
In this example, the topic string involves the repetition of Mars. Four different things are said about Mars: its location and name; its reddish appearance; its prefix name; its moons. When you start analyzing paragraphs for topic strings, you can more readily see minor organizational flaws: in this example, the two sentences that discuss the planet's name could be put together rather than interrupted by the reddish-appearance sentence. Static topic strings like this one are instances of the coordinate paragraph structure: four same-level things are stated about Mars. This paragraph could be diagrammed as follows:
| Sentence beginning | Sentence ending |
| Mars | location, name |
| Mars | name, reddish appearance |
| name, prefixes | Mars |
| Mars | moons |
This diagram identifies the topics at the beginning of the sentences, which are in all but one case Mars. The diagram also identifies the topics at the end of the sentences, which again in all but one case are various aspects of Mars. Is sentence 3 flawed because Mars occurs at the end? No, because the peceding sentences have firmly established Mars as the topic and because beginning every sentence with Mars would create a distracting monotony.
Here's another example of a continuous topic string, but one that doesn't look continuous at first:
| Barely stifled yawns greeted the electronics novelty that was introduced to the public in mid-1948. "A device called a transistor, which has several applications in radio where a vacuum tube ordinarily is employed, was demonstrated for the first time yesterday at Bell Telephone Laboratories," noted an obviously unimpressed New York Times reporter on page 46 of the day's issue. To be sure, the gadget had plusses. Not only could the transistor amplify electric current like a vacuum tube, it also used little power, didn't need to warm up, and was compact—a thimble-sized cylinder with a couple of protruding wires. But because its main ingredient was an expensive, hard-to-handle element called germanium, the transistor seemed likely to remain a laboratory curiosity. |
In this example, the focus is obviously transistor, but notice the synonyms used to refer to this topic:
| Sentence beginning | Sentence ending |
| electronics novelty | date |
| transistor | lack of interest, usefulness |
| gadget | plusses |
| transistor | positive features |
| germanium problem or transistor |
transistor or lab curiosity |
Is this good writing, or bad? The excerpt seems to violate the rule about calling a object or an action by the same name. But for some reason this variation seems appropriate—probably because is creates a little suspense, which is relieved when the well-known term transistor is unveiled.
If you had problems analyzing the topics in the preceding example, you are not alone. The reason is the lack of precision in this method of analysis. All clauses—not just independent ones but dependent ones as well—have a beginning and ending topic. In dependent clauses, the beginning topic is not always directly expressed. However, finetuning this analysis to include all clauses may reduce its usefulness as a tool for ordinary writers. But here's an effort:
| Clause beginning | Clause ending |
| yawns | electronics novelty |
| that (electronics novelty) | introduction date |
| which (transistor) | vaccuum-tube-like applications |
| transistor | demonstration location, date |
| gadget | plusses |
| transistor | vaccuum-tube-like function |
| it (transistor) | positive features |
| its | germanium problem |
| transistor | laboratory curiosity |
Now you can see that transistor, some synonym for it, or some pronoun such as that, which, or it begins every clause in this excerpt, not just every sentence. Notice some other details about this analytic technique:
Does this more precise method of analyzing topic strings in paragraphs work? Or does its fussy exactitude damage its usefulness as a tool for analyzing and improving paragraphs? Let's vote.
This next example can be analyzed in two ways:
| A solar cell (or a "photovoltaic" cell) is a semiconductor device that converts photons from the sun (solar light) into electricity. To achieve this conversion, the device needs to fulfill only two functions: photogeneration of charge carriers (electrons and holes) in a light-absorbing material, and separation of the charge carriers to a conductive contact that will transmit the electricity. This conversion is called the photovoltaic effect, and the field of research related to solar cells is known as photovoltaics. |
Obviously, the focus is solar cell, but each sentence focuses on the conversion process it achieves:
| A solar cell (or a "photovoltaic" cell) is a semiconductor device that converts photons from the sun (solar light) into electricity. To achieve this conversion, the device needs to fulfill only two functions: photogeneration of charge carriers (electrons and holes) in a light-absorbing material, and separation of the charge carriers to a conductive contact that will transmit the electricity. This conversion is called the photovoltaic effect, and the field of research related to solar cells is known as photovoltaics. |
In this second analysis, the initial instance of solar cell is highlighted because it begins the discussion. The focus of the discussion then shifts to conversion. It's useless to argue whether the continuous topic string here is solar cell or conversion. It is useful, however, that the process of analyzing paragraphs for topic strings enables you to see these two patterns.
As the final example in the preceding section hints, the topics in a topic string sometimes vary; they don't just repeat the same old topic. In this case, you have a variable or shifting topic string. Here's that Mars example again, but in its original version:
| Mars is the fourth planet from the Sun in our solar system and is named after Mars, the Roman god of war. Mars is also known as the "Red Planet" due to its reddish appearance when seen from Earth. The red/orange appearance of Mars' surface is caused by iron oxide. The prefix areo-, from the Greek god of war, Ares, refers to Mars in the same way geo- refers to Earth. Mars has two moons, Phobos and Deimos, which are small and oddly-shaped. |
In this example, the topic string still involves the repetition of Mars. This time, five different things are said about Mars: its location and name; its reddish appearance; the reason for the reddish appearance; its prefix name; its moons. The second occurrence of appearance creates a single disruption in the essentially continuous topic string.
Look closely at what's happening in this second Mars example: sentence 2 starts with the topic Mars then ends with the topic reddish appearance; sentence 3 starts with reddish appearance and then ends with a causal explanation for that reddish appearance, signaled by the words is caused by. This pattern is called by Joseph M. Williams and others the old-to-new pattern.
| Sentence 2 | Sentence 3 |
| Mars > reddish appearance | red/orange appearance > Mars |
This example shifts for one sentence to a new topic then back to the old topic. Here is another example in which the old-to-new shift is not so temporary:
| The surface of Mars is thought to be primarily composed of basalt, based upon the Martian meteorite collection and orbital observations. There is some evidence that a portion of the Martian surface might be more silica-rich than typical basalt, perhaps similar to andesitic stones on Earth, though these observations may also be explained by silica glass. Much of the surface is deeply covered by iron oxide dust as fine as talcum powder. There is conclusive evidence that on the surface of Mars liquid water existed at one time. Key discoveries leading to this conclusion include the detection of various minerals such as hematite and goethite which usually only form in the presence of water. |
At first, you may have throught, "Oh, yes. Another paragraph about Mars." However, if you look more closely, you see that surface occurs in the first three sentences but not in the last, where water is the topic. In the pivotal sentence 4, the focus shifts from surface to water. This is another old-to-new topic shift. In sentence 4, the old topic, surface, occurs appropriately at the beginning of the sentence; and the new topic, water, occurs appropriately toward the end of sentence 4. Scholars of writing technique advocate starting a sentence with familiar information (topics that have already been introduced) and then ending sentences with new information (new topics). Otherwise, starting each sentence with a new topic puts a cognitive strain on readers, making them work much harder, harder than necessary, to understand the discussion.
However, the old-to-new shift can go on multiple times. When that happens, the writer is going deeper and deeper into the overall topic of the paragraph. In terms of paragraph coordination and subordination, the writer is creating a highly subordinate structure with a shifting topic string. A continuous topic string, on the other hand, is a highly coordinate structure. Here's an example:
| The most important part of a solar heating system is the solar collector whose main function is to heat water to be used in space heating. There are various types of collectors. However, the flat-plate collector is the most common and the focus of the following discussion. A flat-plate collector consists of a box-shaped black plate absorber covered by one or more transparent layers of glass or plastic with the sides and the bottom of the box insulated. These layers of glass or plastic have an intervening air space that produces the heat-trapping effect. Water is heated as it circulates through or below the absorber component, which is heated by solar radiation. |
| Clause beginning | Clause ending |
| solar heating system | solar collector |
| types | collectors |
| flat-plate collector | most common (type) |
| flat-plate collector | layers |
| layers | heat-trapping effect |
| (water) heated | (circulation) |
The topic string in this paragraph is predominately shifting:
Do these variations and distortions of the perfect old-to-new pattern cause any coherence problems? Probably not: enough sentences follow the pattern and the repetition of key topic words is strong enough to create what seems a reasonably coherent discussion. But let's vote!
Analyzing topic strings in paragraphs can be a useful tool in determining why paragraphs might be difficult to read, follow, and understand. This analysis enables you to gauge how much mental work you are making your readers do. Read this discussion first to see if you understand it, or if it takes you a couple of readings to understand it:
|
1 The development of the transistor goes back to the nineteenth century. 2 Germanium and silicon, along with a number of other crystalline materials, are semiconductors, so-called because they neither conduct electricity well, like most metals, nor block it effectively, as do insulators such as glass or rubber. 3 Back in 1874 a German scientist named Ferdinand Braun identified a surprising trait of these on-the-fence substances: Current tends to flow through a semiconductor crystal in only one direction. 4 This phenomenon, called rectification, soon proved valuable in wireless telegraphy, the first form of radio communication. 5 When electromagnetic radio waves traveling through the atmosphere strike an aerial, they generate an alternating (two-way) electric current. 6 However, earphones or a speaker must be powered by direct (one-way) current. 7 Methods for making the conversion, or rectification, in wireless receivers existed in the closing years of the 19th century, but they were crude. 8 In 1899 Braun patented a superior detector consisting of a semiconductor crystal touched by a single metal wire, affectionately called a "cat's whisker." 9 His device was popular with radio hobbyists for decades, but it was erratic and required much trial-and-error adjustment. |
Most people would find this excerpt hard going. It gives your brain a workout — which may be a good thing, after all. However, if you believe that readers deserve text that can be undserstood as effortlessly as possible, this excerpt needs some work. Here's the analysis:
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