Paragraphs

The key building block of essays is the paragraph. A paragraph represents a distinct logical step within the whole argument. That step may be big or little; it may take one or ten sentences to lay out—but the key is that it is one step.

　　Thus there's no point in laying down as a rule （as one sometimes hears） that paragraphs should be four or five sentences long. That's probably a decent guideline for most paragraphs in student writing, but in good writing you'll find longer paragraphs and shorter paragraphs—some as short as a single sentence, if that's all it takes for that particular thought （use one-sentence paragraphs sparingly, but don't flinch from them when they're what you need）.

　　Paragraphs are discrete steps in one's argument, but that doesn't mean that every step in the argument must fit within a single paragraph. Some complex thoughts may require so much space to explicate that the resulting paragraph would be two pages long. In such cases, break into smaller units, looking to subdivide along some sensible and clear scheme.

　　The basic idea is simple but crucial: When you write a paragraph, you should know what it is meant to do. If your answer is simply, "Well, this paragraph helps explain my topic," then you haven't thought deeply enough. How does this particular paragraph contribute to the argument? What logical step does it make? Where does it fit in the overall chain?