An important quality of an effective paragraph is unity. A unified paragraph sticks to one topic from start to finish, with every sentence contributing to the central purpose and main idea of that paragraph.
But a strong paragraph is more than just a collection of loose sentences. Those sentences need to be clearly connected so that readers can follow along, recognizing how one detail leads to the next. A paragraph with clearly connected sentences is said to be cohesive.
Repetition of Key Words
Repeating key words in a paragraph is an important technique for achieving cohesion. Of course, careless or excessive repetition is boring--and a source of clutter. But used skillfully and selectively, as in the paragraph below, this technique can hold sentences together and focus the reader's attention on a central idea.
We Americans are a charitable and humane people: we have institutions devoted to every good cause from rescuing homeless cats to preventing World War III. But what have we done to promote the art of thinking? Certainly we make no room for thought in our daily lives. Suppose a man were to say to his friends, "I'm not going to PTA tonight (or choir practice or the baseball game) because I need some time to myself, some time to think"? Such a man would be shunned by his neighbors; his family would be ashamed of him. What if a teenager were to say, "I'm not going to the dance tonight because I need some time to think"? His parents would immediately start looking in the Yellow Pages for a psychiatrist. We are all too much like Julius Caesar: we fear and distrust people who think too much. We believe that almost anything is more important than thinking.Notice that the author uses various forms of the same word--think, thinking, thought--to link the different examples and reinforce the main idea of the paragraph. (For the benefit of budding rhetoricians, this device is called polyptoton.)
(Carolyn Kane, from "Thinking: A Neglected Art." Newsweek, December 14, 1981)
Repetition of Key Words and Sentence Structures
A similar way to achieve cohesion in our writing is to repeat a particular sentence structure along with a key word or phrase. Although we usually try to vary the length and shape of our sentences, now and then we may choose to repeat a construction to emphasize connections between related ideas.
Here's a short example of structural repetition from the play Getting Married by George Bernard Shaw:
There are couples who dislike one another furiously for several hours at a time; there are couples who dislike one another permanently; and there are couples who never dislike one another; but these last are people who are incapable of disliking anybody.Notice how Shaw's reliance on semicolons (rather than periods) reinforces the sense of unity and cohesion in this passage.
On rare occasions, emphatic repetitions may extend beyond just two or three main clauses. Not long ago, the Turkish novelist Orhan Pamuk provided an example of extended repetition (specifically, the device called anaphora) in his Nobel Prize Lecture, "My Father's Suitcase":
The question we writers are asked most often, the favorite question, is: Why do you write? I write because I have an innate need to write. I write because I can’t do normal work as other people do. I write because I want to read books like the ones I write. I write because I am angry at everyone. I write because I love sitting in a room all day writing. I write because I can partake of real life only by changing it. I write because I want others, the whole world, to know what sort of life we lived, and continue to live, in Istanbul, in Turkey. I write because I love the smell of paper, pen, and ink. I write because I believe in literature, in the art of the novel, more than I believe in anything else. I write because it is a habit, a passion. I write because I am afraid of being forgotten. I write because I like the glory and interest that writing brings. I write to be alone. Perhaps I write because I hope to understand why I am so very, very angry at everyone. I write because I like to be read. I write because once I have begun a novel, an essay, a page I want to finish it. I write because everyone expects me to write. I write because I have a childish belief in the immortality of libraries, and in the way my books sit on the shelf. I write because it is exciting to turn all life’s beauties and riches into words. I write not to tell a story but to compose a story. I write because I wish to escape from the foreboding that there is a place I must go but--as in a dream--can’t quite get to. I write because I have never managed to be happy. I write to be happy.Two well-known examples of extended repetition appear in our Essay Sampler: Judy Brady's essay "Why I Want a Wife" (included in part three of the Essay Sampler) and the most famous portion of Dr. Martin Luther King, Jr.'s "I Have A Dream" speech.
(The Nobel Lecture, 7 December 2006. Translated from the Turkish, by Maureen Freely. © The Nobel Foundation 2006)
Final Reminder: Needless repetition that only clutters our writing should be avoided. But the careful repetition of key words and phrases can be an effective strategy for fashioning cohesive paragraphs.