Unity and Coherence: Study Guide (English Language 5.2)

Two words, two jobs

Unity and coherence are often confused. Both describe a text that works well, but they work at different points.

• Unity is staying on one idea. A unified paragraph has a controlling claim, and every sentence in it serves that claim. A sentence about something else, however interesting, breaks the unity.
• Coherence is holding together. A coherent text has ideas that are linked so that each leads logically to the next. A reader can follow the argument without having to guess the connection.

The course framework describes coherence at three levels:

Level	What links to what	A reader’s question
Sentence (within a sentence)	The idea in one clause links to the idea in the next	“How does this clause relate to the last one?”
Paragraph (within a paragraph)	The idea in one sentence links to the idea in the next	“How does this sentence follow?”
Text (between paragraphs)	The ideas in one paragraph link to the ideas in the next	“Why does this paragraph come here?”

A strong writer pays attention to all three. A text can be coherent at the paragraph level and still fail overall if one paragraph arrives from nowhere.

How ideas link

There are several ways a writer can make one idea lead to the next.

By logical relationship. The next idea can be a result, a reason, an example, a contrast, a qualification or a consequence of the previous one. The writer decides which and makes it clear. (Topic 5.4 shows how transitional elements signal this.)

By known-then-new order. A reader finds a sentence easier to follow when it begins with something already mentioned and ends with something new. For example: The town built a bypass. The bypass diverted traffic from the high street. Without the traffic, the shops found it easier to attract walkers. Each sentence starts with what the last one ended on.

By repeated key terms, synonyms and pronouns. Words that recur, or that stand in for earlier words, tie sentences together (Topic 5.3).

By parallel structure. Parallel phrasing signals that ideas have the same status.

By the order of paragraphs. The order should reflect the line of reasoning: problem, then cause, then solution; or claim, then evidence, then qualification.

What breaks unity and coherence

Problem	Symptom	Likely repair
Off-topic sentence	A sentence that serves another idea	Cut, or move it to a paragraph where it belongs
Jump between ideas	The next sentence seems unrelated	Add the missing idea, reorder, or add a transition that states the relation
Order that fights the logic	A conclusion appears before its evidence	Reorder
Shifting vocabulary	Key term changes (for example “cost”, then “price”, then “expense”) without reason	Keep one key term or add a clear link
Vague pronouns	“This” or “it” has no clear referent	Name the noun
Paragraph with two main ideas	Two controlling claims in one paragraph	Split it

Weak and strong versions side by side

Weak (Marlbridge example).

Bicycles are cheap to own. The town has a new bypass. Many people like to cycle at weekends. A cycle lane would be inexpensive to build. Some cyclists wear helmets.

The sentences all touch on cycling but do not work together. The reader cannot tell what the paragraph is for.

Strong (Marlbridge example).

A cycle lane would be an inexpensive way to reduce traffic on the high street. A lane costs a small fraction of what a new road costs, and it can be built along streets the town already owns. Once the lane exists, short journeys that currently go by car, such as the trip to the shops or the school, become safer by bicycle. As those journeys move to bicycles, the high street has fewer cars, and the bypass the town has just built has less to compensate for.

Feature	Weak	Strong
Unity	Five loosely related ideas	One controlling claim (a cycle lane is an inexpensive way to reduce traffic)
Sentence-to-sentence links	None	Each sentence begins with what the last one ended on (“a lane”, “the lane”, “those journeys”)
Logic	Unclear	Cost, then effect on journeys, then effect on traffic
Paragraph link	None	Ends on the bypass, which may introduce the next point

Worked example 1: revising a paragraph for unity and coherence

Draft (Marlbridge example).

Our school canteen should offer more vegetarian meals. Lunch is served between 12:00 and 1:00. Vegetarian meals are often cheaper to make. Some students eat packed lunches. More students would buy lunch if there were more choice. Kitchens must follow food-safety rules.

Step 1: Identify the controlling idea. The first sentence: the canteen should offer more vegetarian meals. The remaining sentences must serve it.

Step 2: Test each sentence for unity.

• “Lunch is served between 12:00 and 1:00.” Irrelevant to the claim. Cut.
• “Vegetarian meals are often cheaper to make.” Relevant: a reason for the canteen.
• “Some students eat packed lunches.” Relevant only if linked: if students bring packed lunches because the choices are poor, it supports the claim.
• “More students would buy lunch if there were more choice.” Relevant: a reason.
• “Kitchens must follow food-safety rules.” Irrelevant, unless used to answer an objection. Cut.

Step 3: Reorder for logic. The reasons should lead from the problem (students not buying) to the benefit (the canteen gains customers) to the cost (cheaper to make).

Step 4: Link the sentences.

Our school canteen should offer more vegetarian meals. At present, many students bring packed lunches because the choice on offer does not suit them, which means the canteen loses customers it could keep. A wider vegetarian menu would draw those students back, and because vegetarian meals are often cheaper to make, the canteen could afford to offer them without raising prices.

Step 5: Check. Unity: every sentence serves the controlling claim. Coherence: “packed lunches” leads to “lose customers”, “those students” refers back, “because” links cost to the benefit.

Worked example 2: how coherence works in a published passage

Thomas Paine opens The American Crisis (1776) with these lines:

These are the times that try men’s souls. The summer soldier and the sunshine patriot will, in this crisis, shrink from the service of their country; but he that stands it now, deserves the love and thanks of man and woman. Tyranny, like hell, is not easily conquered; yet we have this consolation with us, that the harder the conflict, the more glorious the triumph.

Step 1: Within sentences (clause to clause). In the second sentence, the semicolon and “but” turn the clause about those who “shrink” into a clause about the one who “stands it now”. The contrast between two kinds of people is built into a single sentence. In the third sentence, “yet” turns the admission that tyranny is hard to conquer into a consolation.

Step 2: Between sentences. “These are the times that try men’s souls” states the situation. The second sentence says who fails and who passes the trial (“in this crisis”). The third gives reasons to continue despite difficulty. Each sentence builds on the last: crisis, then the test of character, then the reward.

Step 3: Repeated and related terms. “Times”, “crisis”, “stands it”, “conflict” form a chain of words related to difficulty; “triumph” and “glorious” form a chain related to reward. The parallel “the harder the conflict, the more glorious the triumph” links the two chains.

Step 4: Write the analysis sentence. Paine achieves coherence by moving from the crisis, to the test it poses, to the reward for passing it, and by linking the sentences with “but” and “yet”, so that his audience hears difficulty and glory as parts of the same idea.

Common misconceptions

• “Coherence means using more transitions.” Transitions help only if the ideas really connect.
• “Unity means every sentence repeats the same point.” Unity means every sentence serves the controlling idea, not that they repeat it.
• “A paragraph is coherent if all sentences are on the same topic.” That is unity at best. Coherence requires logical links.
• “Coherence is only about paragraphs.” It also operates within sentences and across the whole text.
• “I should cut every sentence that does not repeat the thesis.” A paragraph needs evidence and commentary as well as claims.
• “If I change the order of paragraphs, nothing changes.” The order is part of the line of reasoning; changing it alters how the argument reads.

Where this leads

The next topics give you the specific tools of coherence. Topic 5.3 looks at repetition, synonyms, pronouns and parallel structure, and Topic 5.4 at transitional elements. To revisit paragraph structure, see Topic 5.1. Check your learning with the practice questions, the revision notes and the checklist.