THUS FAR we have considered essays mainly at the level of individual words and sentences (though in Chapter 3 we considered flow from one sentence to the next). Now we turn our attention to larger structural elements, starting with paragraphs.
What are paragraphs? In essence, a form of punctuation—and like other forms of punctuation, they are meant to make written material easier to read. Visually, paragraphs are blocks of text marked with an indented first line (usually a half-inch indent; for college essays it's better to indent than use a blank line). Functionally, paragraphs represent pieces of an argument. Lincoln's Gettysburg Address, for instance, consists of just three short paragraphs: the first about the past, the second the present, and the third the future. Lincoln, a great communicator, chose this simple structure to reinforce his speech's intention. He wished to evoke in the minds of his audience an emotional link between America's founding, the present conflict, and the enduring values for which he said Americans were fighting. The harmony of the design helped make this the most famous speech in our nation's history.
Of course there are countless ways to structure arguments, and thus countless ways to arrange an essay into paragraphs. But any sound arrangement requires the writer to do three things: (1) understand your own argument (What do I wish to say to the reader?); (2) decide on a sensible way to lay out this argument (From the reader's perspective, what piece-by-piece arrangement of supporting and explanatory material will best illuminate the argument?); and (3) have the discipline to stick to this structure (Does each paragraph—and each sentence—fit with my plan?). (In practice there's a fourth requirement—willingness to modify your design as the need arises.) The most important thing to remember is that paragraphs are there for your reader's benefit, not because of some abstract rule of composition.