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Main Idea versus Controlling Idea

26 January, 2015 - 15:57

Topic sentences contain both a main idea (the subject, or topic that the writer is discussing) and a controlling idea (the writer’s specific stance on that subject). Just as a thesis statement includes an idea that controls a document’s focus (as you will read about in "The Writing Process: How Do I Begin?"), a topic sentence must also contain a controlling idea to direct the paragraph. Different writers may use the same main idea but can steer their paragraph in a number of different directions according to their stance on the subject. Read the following examples.

  • Marijuana is a destructive influence on teens and causes long-term brain damage.
  • The antinausea properties in marijuana are a lifeline for many cancer patients.
  • Legalizing marijuana would create a higher demand for Class A and Class B drugs.

Although the main idea—marijuana—is the same in all three topic sentences, the controlling idea differs depending on the writer’s viewpoint.