Bain’s idea of the paragraph as a single developed thought came to rule over the school lesson and composition class. Students were taught that a paragraph should have a topic sentence stating the main idea, supporting sentences that amplified that idea, and a wrap-up sentence revisiting the idea. George Gopen calls this the Wizard of Oz paragraph, with its middle three sentences chanting because, because, because. The trouble with this sort of paragraph is that its life is over by the first sentence and the others are just there to write its obituary.
