Story has it that Albert Einstein learned to talk very late in infancy, but when he finally spoke he did so in complete sentences--a sign of his lateblooming genius. Yet no one, no matter how oratorically brilliant, is seriously credited with speaking spontaneously in paragraphs. The paragraph is a convention of the written word. Since most of us have no innate "ear" for paragraphs, we have to spend considerable effort and practice perfecting an "eye" for them.
Paragraphs divide the flow of prose into manageable portions. The paragraph break signals an opportunity to pause, reflect, and assimilate; it may alert readers to a summary, transition, or shift in emphasis. Simply put, paragraphs keep readers from getting lost. They serve a similar function for writers too, keeping them from wandering off into irrelevant chains of association. In composition the paragraph provides an essential unit of organization, large enough to contain several sentences but small enough to be held in immediate memory. Practiced writers find, even though they may not speak in paragraphs, that they definitely think in paragraphs, at least when they sit down to write.
Follow the links for advice on paragraph construction and length.
At some point in your education you probably encountered a model, scheme, or formula for a well-made paragraph. Most likely this formula involved a thesis sentence, two or three sentences of development, and a conclusion that recapitulates the thesis. This "five-sentence paragraph" and its scaled-up counterpart, the "five-paragraph theme," cause great consternation among college teachers. Formulas like these may be useful in some contexts--for instance, when you must write quickly under pressure, as in an examination essay. But even then you should remember that rigid, five-part models may constrain your expression and limit the development of your ideas. If your writing is to help you grow as a thinker, you must realize that regular models are of only incidental importance. Good writers learn to work through and beyond them.
Consider instead a more flexible and sophisticated definition of the paragraph: a series of statements that expresses a sequence of thought--a definition, an exploration, a demonstration, or a critique--set in some relation to a central idea. There is no single "correct" pattern for this sequence of thought. The design of a paragraph should be dictated by your purpose in writing it, and in this regard it may be useful to think of certain traditional "modes" of expression: description, definition, narration, causal analysis, deductive or inductive reasoning, comparison and contrast. The mode of a paragraph largely determines its structure--for instance, a paragraph that leads deductively from one proposition to another might be organized symmetrically around the two poles of premise and conclusion, while a paragraph of causal analysis is more likely to form itself into an extended string of relationships tracing a path toward or away from a single statement.
But although this flexible approach to paragraph structure is superior to the "five-sentence paragraph," one aspect of the simpler model is worth preserving: its emphasis on a central idea. You need not feel obliged to place a "thesis sentence" at the head of every paragraph, but there should come a point at which your reader can recognize a main idea, a point of focus, or an argumentative climax. A good paragraph is not a loose series of unrelated thoughts. There must be some pattern of subordination or connection even in a paragraph whose structure is digressive or repetitive, and it is impossible to construct such a system of transitions and relationships in the absence of a main idea.
The architecture of paragraphs is a surprisingly rich subject. You can learn much about the way writers think by the way they build their paragraphs. Make a habit of noticing this architecture when you read, both to expand your own repertoire of structures and to promote your understanding of the material.
A good paragraph is as long as it needs to be. Just as there is no universal blueprint for paragraph structure, so there is no absolute minimum or maximum standard for length. If a paragraph is a sequence of thought, then part of the discipline of writing (and thinking) is knowing when this sequence has arrived at its goal.
Some broad rules of thumb do apply, though they are subject to exceptions. If a single paragraph exceeds a double-spaced page or (if single spaced) a small computer screen, reconsider its length. If the paragraph contains a large number of sentences (more than six or seven), see if you can find a place or places to divide it. If such a large paragraph contains only three or four sentences, chances are your sentences are either full of unnecessary words or hopelessly convoluted. Go back and condense.
The most serious difficulty inexperienced writers have with paragraphs arises not from excessive length but from insufficient development. All too often, especially under the pressure of a deadline, students string together two or three as yet unrelated assertions and present them as a fully-formed train of thought. Here is one such stunted paragraph:
The American economy faces unprecedented competitive pressure from other industrialized nations. Only by maintaining our superiority in basic research can we hope to survive in this situation. Greater support for universities is essential.
This is a "paragraph" only by the most liberal definition; it more closely resembles an entry in a notebook. The writer has drawn only cursory links between assertions, and these assertions are not supported by demonstration or evidence. There is no attempt to pursue implications or consider implicit assumptions. This writing would not be acceptable in a formal academic essay. Fortunately, however, this writer had another chance. Here is what the proto-paragraph became in a second draft:
The American economy faces unprecedented competitive pressure from other industrialized nations. The British, French, West Germans, and above all the Japanese have spent billions to modernize their industries and expand into new markets. The key to this expansion is basic research that does not need to have a quick payoff--the investigation of fundamental principles in chemistry, physics, and biology research. Basic research in materials technology launched superconductivity, which may become one of the three most important technologies of the next century. If the U.S. is to stay competitive with Japan and Europe, we must expand our efforts in basic research.
This version is longer, but it is also more specific, more precise, and better focused. The first assertion, about competitive pressure, has been supported with references to the Europeans and Japanese. The second assertion, about basic research, has been expanded--we now know what basic research is--and bolstered with the reference to superconductivity. The third assertion, about support for universities, has been moved to a separate paragraph and in its place there is a sentence that summarizes and points ahead to further development.
The fact that this improved paragraph leads on to later discussion brings up another common pitfall of paragraph construction: integrating paragraphs into the larger structure of an argument. Paragraphs in an essay, like sentences in a paragraph, have to be assembled according to some logical scheme. The first sentence of the paragraph usually serves as the "hook" that links one paragraph to another. By the same token the final sentence may provide a "signpost" that informs readers where the argument is about to take them. These transitional sentences are placed at the seams or border lines of an essay, the points where the structure of analysis and argument is often weakest. Therefore the transitions between paragraphs are often the most interesting parts of an essay. They are the points where opportunities for extension and refinement are greatest.
If the logic of a paragraph seems unclear to you or a second reader, consider adding transitional material. If you can think of no necessary connection between paragraphs, reconsider their order in your essay. Writing with a word processor makes changing the sequence of paragraphs a fairly simple task. When "cutting and pasting" blocks of text, be sure you do not introduce inconsistencies (for instance, by relying on arguments that formerly came before but after re-ordering come later). Be prepared to write new transitions to knit the recombined structure together.
Copyright 1996 Yale University. Revised on Monday, May 20, 1996