To evaluate the logic of an argument, you first decide whether the argument’s reasons and support are appropriate. To test for appropriateness, ask these questions: How does each reason or piece of support relate to the thesis? Is the connection between reasons and support and the thesis clear and compelling?

Readers most often question the appropriateness of reasons and support when the writer argues by analogy or by invoking authority. For example, in paragraph 2, King argues that when law and order fail to establish justice, “they become the dangerously structured dams that block the flow of social progress.” The analogy asserts the following logical relationship: Law and order are to progress toward justice what a dam is to water. If you do not accept this analogy, the argument fails the test of appropriateness.

King uses both analogy and authority in paragraph 3: “Isn’t this like condemning Socrates because his unswerving commitment to truth and his philosophical inquiries precipitated the act by the misguided populace in which they made him drink hemlock?” Not only must you judge the appropriateness of the analogy comparing the Greeks’ condemnation of Socrates to the white moderates’ condemnation of King, but you must also judge whether it is appropriate to accept Socrates as an authority. Since Socrates is generally respected for his teachings on justice, his words and actions are likely to be considered appropriate to King’s situation in Birmingham.