An analogy is a composition in which one idea, process, or thing is described by comparing it to something else.

Extended analogies make a complicated process or idea easier to comprehend. In this piece, we assess the qualities of successful analogies and consider the value of employing metaphors in our writing.
The analogy is “reasoning or explaining from parallel cases.” Explained another way, a metaphor is a contrast between two things to highlight some point of similarity. As Freud suggested, an analogy won’t resolve an argument, but a great one may help to explain the issues.

Does this mean that our memory functions precisely like a computer? No. An analogy offers a plain view of an idea or process—an design rather than a detailed assessment.

Comparison & Contrast

An analogy is not the same as comparison and contrast, although each method of explanation places things side by side. Writing in The Bedford Reader, X.J. and Dorothy Kennedy explain the difference:

In writing a comparison and contrast, you may demonstrate how San Francisco is unlike Boston in history, climate, and prevalent lifestyles but like it in being a port and a city pleased with its colleges. But, regrettably, that isn’t the way an analogy operates. Instead, with an analogy, you place together two dissimilar and want to understand their similarities.

The highly effective analogies are brief and to the point—developed in just a few sentences. That said, in the hands of a gifted writer, an extended metaphor can be illuminating.

Analogy and Argument

Suppose it takes a couple of sentences or an essay to build an analogy; we must be careful not to go too far. Just because two subjects have one or two similar points doesn’t mean they are the same in other respects.