Style: Paragraphs

 

Page contents:

topic sentences and supporting sentences
paragraph length

 

Topic Sentences and Supporting Sentences

A paragraph is a group of sentences that deals with a single topic, typically comprising a topic sentence (often the first) and a number of supporting
sentences that explore or develop it –

      Progress in urban sanitation has been erratic and piecemeal. Conditions
      in eighteenth-century England, for example, were better than they were
      to become at the height of the Industrial Revolution. In the first half of
      the nineteenth century, the populations of London, Leeds and Birmingham
      doubled, far exceeding available housing, and the per capita death rate
      increased by almost 100 per cent.

The topic sentence (underlined) tells us what the paragraph is to be about, while its remainder consists of supporting sentences that explain the
details or provide the evidence. In other words, the topic sentence is general while the supporting sentences are 
specific, developing the topic by
means of examples, descriptions, definitions, comparisons and explanations.

Ideally, the topic sentences of the paragraphs of an article or essay should collectively give us a concise account of the entire script. For example,
if we take the above passage to be the beginning of an article on urban sanitation, the rest of the article might 
read like this –

      However, a number of remedial developments were taking place. In
      1838, the newly created Poor Law Commission suggested that the cost
      of sanitary improvements would be less than the social cost occasioned
      by the diseases they would help prevent. Economists and philanthropists
      were also voicing their concerns, among them Thomas Southwood Smith
      who advanced the importance of quarantine for victims of cholera and
      yellow fever.

      But it was not until 1848 that the first attempt was made in England to 
      create a centralised authority to effect improvements in urban sanitation.
      The Public Health Act of that year created a General Board of Health to
      offer advice to local authorities, paving the way for regulations on such
      things as sewage, water supply and refuse disposal.

The underlined topic sentences thus provide a summary of the article –

      Progress in urban sanitation has been erratic and piecemeal. A number of
      remedial developments had earlier taken place, but it was not until 1848 
      that the first attempt was made in England to create a centralised authority 
      to effect improvements.

This might well have been how the article began, the author first arranging her thoughts into general topics before filling them out into paragraphs 
with supporting sentences.

But the topic sentence need not come first. Like sentences, paragraphs can be loose (with the topic sentence at the beginning), as above, or
periodic (with the topic sentence at the end) –

      Conditions in eighteenth-century England were better than they were
      to become at the height of the Industrial Revolution. In the first half of
      the nineteenth century, the populations of London, Leeds and
      Birmingham doubled, far exceeding available housing, and the per
      capita death rate increased by almost 100 per cent. Progress in urban
      sanitation, then, has been erratic and piecemeal.

Again like sentences, loose paragraphs are the more common because they have the advantage of acquainting the reader quickly with the topic.
The periodic paragraph, on the other hand, can be effective in building up the argument first, so that the reader more easily sees the main point
when it is made –

      With the advent of DNA testing, it is arguably now all but impossible
      to convict an innocent person of murder, thus putting paid to one of the
      central arguments against the death penalty. Yet members of juries, no
      matter how hawkishly they might have defended capital punishment in
      their living rooms and in their cups, frequently shied away from guilty
      verdicts when hanging was an option. DNA or no, this reluctance to
      convict, which resulted in more murderers being freed, still provides one
      of the strongest arguments against the restoration of capital punishment.

Another option is the mixed paragraph, with the topic sentence (or the topical clause of a sentence) located somewhere inside –

      Conditions in eighteenth-century England were better than they were to
      become at the height of the Industrial Revolution, illustrating that
      progress in urban sanitation has been erratic and piecemeal. In the first
      half of the nineteenth century, for example, the populations of London,
      Leeds and Birmingham doubled, far exceeding available housing, and
      the per capita death rate increased by almost 100 per cent.

The mixed paragraph is a useful device when the writer wishes to contradict or amend another’s argument –

      Smith (1973) claims that the Cuban missile crisis of 1962 represented a
      political coup for the United States. As he correctly points out, the States’
      indisputable nuclear superiority over the USSR, as well as its over-
      whelmingly greater naval and air power in the vicinity, gave Khrushchev
      no alternative but to back down. However, there are at least two compelling
      reasons to suggest that the Soviets emerged as the real victors. Firstly, the
      crisis led to Kennedy’s promise never to attempt to oust Castro, in effect
      acknowledging the permanence of a Communist neighbour. Secondly, it
      strengthened the Soviets’ resolve never again to be humiliated, so that in less
      than ten years the USSR had a nuclear capability that easily matched that of
      the United States.

The writer’s topic here is a counter claim to that of another writer. She cites that writer's topic first, adding her own paraphrases of that writer's
supporting sentences, and then introduces her own topic sentence (underlined) before adding her own supporting evidence.

But it should not be supposed that every paragraph should have one, and only one, clear topic sentence. Each of the above examples has to 
some extent been contrived in order to illustrate a point, but there is room for ambiguity –

      The problems began to emerge just two months after the windows were
      fitted. First, as the March winds set in, we noticed the draughts from the
      living room and bedroom vents. Then the damp patches appeared around
      the frames and, within a year, condensation appeared between some of
      the panes, announcing that the vacuum seals had been broken. So much

      for bargain prices! I firmly believe now that you get only what you pay for.

Here, the opening sentence appears to be the topic sentence. It promises that the paragraph will be about the problems of the fitted windows, 
which indeed most of it is, followed by supporting sentences giving the details. But then the opening sentence is knocked off its perch by the
last two sentences which introduce a more general and hence more topical point. A loose paragraph is in effect transformed into a periodic.

Paragraphs can also happily exist without topic sentences, provided the writer is sufficiently skilled to convey the topic implicitly –

      By the mid-1990s, said the prophets of IT, the spread of computers to all
      aspects of human activity would result in a ‘paperless society’. The rapid
      spread and sophistication of information technology would make printed
      copies of all but the most formal of documents redundant. Henceforth, we
      would be reading our newspapers, books and letters on screen. How 
      wrong they were! Everyone, it seems, needs a hard copy.

We search in vain here for a clear topic sentence, but we easily understand what the paragraph is about without its topic being made explicit. All 
that matters in paragraphing is that the reader can detect fairly clear units of discrete but related ideas, and if this can be achieved without topic
sentences, then they are not needed.

 

Paragraph Length

Choosing the length of paragraphs is more a matter of judgement than rule for, besides dividing a script into its logical components, paragraphs
provide resting places for the reader. An entire page without a paragraph break might be grammatically correct but it will 
present most readers
with the daunting prospect of a mental marathon. A succession of short paragraphs, on the other hand, can 
patronise readers and give them the
impression that nothing is being discussed in any depth.

The case for judgement over rule is strengthened by the lack of a precise definition of a single topic. In cases where the writer is going to develop
a point at some length, she is perfectly at liberty to divide a ‘single topic’ into sub-topics for ease of reading. To 
develop an earlier example –

      Smith (1973) claims that the Cuban missile crisis of 1962 represented a
      political coup for the United States. As he correctly points out, the 
      States’ indisputable nuclear superiority over the USSR, as well as its
      overwhelmingly greater naval and air power in the vicinity, gave
      Khrushchev no alternative but to back down. However, there are at least
      two compelling reasons to suggest that the Soviets emerged as the real
      victors.

      Firstly, the crisis led to Kennedy’s promise never to attempt to oust
      Castro, in effect acknowledging the permanence of a Communist
      neighbour. Certainly, there would be attempts to destabilise the country,
      such as ‘zapping’ (implementing an economic boycott), the poisoning of
      crops and even one bizarre plan to kill Castro with an exploding cigar. But
      another invasion was out of the question.

      Secondly, the crisis strengthened the Soviets’ resolve never again to be 
      humiliated, so that in less than ten years the USSR had a nuclear capability 
      that easily matched the USA’s. ICBMs (Intercontinental ballistic missiles)
      were possessed 
by both sides.

The last two paragraphs are arguably no more than supporting sentences of the underlined topic, but to include them on these ground into one
paragraph would succeed only in demoralising the reader.