Subject, purpose, and thesis

The thesis, claim, or main idea in a piece of writing is related to your purpose. As a writer, you usually have a purpose in mind that serves as a guide while you gather information about your subject and think about your audience.

As you collect and record information, impressions, and ideas, however, you gradually narrow your subject to a specific topic, and thus clarify your purpose. You bring your purpose into sharper and sharper focus — as if progressing on a target from the outer circles to the bull's-eye — until you have narrowed your purpose down to a central thesis. The thesis is the dominant idea, explanation, evaluation, or recommendation you want to impress upon your readers.