Bloom defines an analogy as a “comparison made between two things, qualities, or ideas that have certain similarities although the items themselves may be very different.
For example, Scott Russell Sanders characterizes his alcoholic father, “Like a torture victim who refuses to squeal, he would never admit that he had touched a drop, not…” The emphasis is on the similarities between Mr. Sanders, drunk or sober, and the torture victim; dissimilarities would have weakened the analogy. (Bloom 192-203)
An analogy is considered to be a powerful rhetorical tool because it is a “powerful way to emphasize and concretize, hence to help readers understand or to increase emotional impact.” (Coe 331) When we make an analogy, we point out a similarity. We compare two “situations and argue, implicitly or explicitly.” (331) An analogy is when we are comparing our subject with something more “familiar or concrete.” Therefore, an analogy is an important technique which we use in order to clarify our explanations and convince our readers. (Coe 338)
Analogy is a powerful rhetorical tool but its “usefulness and eloquence depend on the author’s ability to convince the audience that both of the terms that are being compared can be rightly connected as a valid analogy.” (Ruse 2008)
Brooke Noel Moore gave the example of Robert Kittle, the editorial page editor of the San Diego Union Tribune who has referred to the Social Security system as a Ponzi scheme. (Ponzi schemes are pyramid schemes designed to bilk money from people who fall for them. Social Security is financially unsustainable; it’s less work and possibly just as effective to call it a Ponzi scheme. (Moore, Critical Thinking 9th ed.)
Ruse, M. The Oxford Handbook of Philosophy of Biology. Oxford University Press US, 2008.