Main Idea and Primary Purpose
What you must be able to do
Separate three related questions: what is the passage about (topic), what does the author want you to accept (main point), and what is the author doing (primary purpose). Purpose answers take the form of a verb plus object - to describe, to argue against, to reconcile, to evaluate, to trace the development of. Main-point answers take the form of a proposition.
Concepts to master
- Scope calibration. The correct answer covers every paragraph, including the last one, which often narrows or qualifies the opening claim.
- Author versus subject. A passage may report a scholar's view for pages and reveal the author's own position in a single concessive sentence. Purpose questions are about the author.
- Verb accuracy. A passage that explains a theory is not a passage that defends it; a passage that questions a claim is not one that refutes it.
Traps
The dominant wrong answers are too broad (a topic label), too narrow (a true statement about paragraph two), and true but secondary. A fourth trap is the right content paired with the wrong verb - "criticize" where the author merely describes, or "prove" where the author only suggests.
Rule of thumb and worked example
Cover the passage and ask which choice you could defend from memory in one sentence.
Suppose a passage explains how a historian challenged the standard account of craft guilds, presents her evidence, then concludes that her revision is persuasive but overshoots in denying any economic function to the guilds. "To describe medieval craft guilds" is too broad. "To prove guilds had no economic function" misstates the author. The best answer: "to assess a revisionist account of the economic role of craft guilds."