there be only one main thought and that all the other thoughts and words in a
sentence, paragraph, or theme directly or indirectly reinforce the one main thought.
Unity requires that thoughts and words that do not either directly or indirectly rein-
force the main thought be omitted from the composition or be clearly marked off by
parentheses or by expressions like permit me to digress for a moment.
Unity requires that digressions be justified and that they be relatively few. Avoid
them as a general rule.
Clearness in writing is largely a matter of unity, coherence, and emphasis. It is
necessary, of course, that the writer's ideas be clear to begin with. But unity, co-
herence, and emphasis go far to make sure that these ideas will also become clear
to the reader.
What unifies a composition often makes it coherent and lends it proper emphasis -
and vice versa. Hence there is a certain amount of overlapping in fact and in rule.
Unity in the sentence
Put into separate sentences ideas that are not plainly related.
If a sentence does not become unwieldy or cluttered, put into it all ideas that are
Do not write rambling, talkative sentences that include too many details.
Save the independent clause of a sentence for the main idea; and do not put two
ideas into two independent clauses unless the ideas are of equal or very nearly
Unity in the paragraph
The topic thought of a paragraph is the one clear, rather brief thought that an-
swers the question What is the paragraph about?
Put one, and only one, topic thought into each paragraph.
Make each sentence of a paragraph develop the topic thought either directly or in-
If the paragraph does not become unwieldy or cluttered, put into it all the ideas
that develop one topic thought
A topic sentence is the topic thought of a paragraph expressed in one sentence of
the paragraph itself. (The topic thought may use up the whole sentence or only
part of it.)
Ordinarily express the topic thought of a paragraph in a topic sentence - unless,
that is, doing so would hurt the paragraph (for example, ruining the suspense).
Some paragraphs cannot be expected to have a topic sentence. That is true of
technical, dialogue paragraphs. It is true also of some narrative paragraphs where
the topic sentence would often have to be something like Here is what happened in
the next ten minutes.