What Is an Analogy?

An analogy is a comparison between two objects, or systems of objects, that highlights respects in which they are thought to be similar. An analogy is something that shows how two things are alike, but with the ultimate goal of making a point about this comparison.

There are seven primary types of relationships used in our analogies: function, degree, lack, characteristic, type/kind, part to whole, and definition.

Analogical reasoning is any type of thinking that relies upon an analogy. An analogical argument is an explicit representation of a form of analogical reasoning that cites accepted similarities between two systems to support the conclusion that some further similarity exists.

Analogical reasoning is fundamental to human thought and, arguably, to some nonhuman animals as well.

The purpose of an analogy is not merely to show, but also to explain. For this reason, an analogy is more complex than a simile or a metaphor, which aim only to show without explaining. (Similes and metaphors can be used to make an analogy, but usually analogies have additional information to get their point across.)

What Is an Example of an Analogy?

Consider this analogy, meant to communicate futility:

“What you’re doing is as useful as rearranging deck chairs on the Titanic.”

Here, the speaker is using a simile to compare the task being done to the task of rearranging deck chairs on the Titanic. But, the ultimate goal is not just to compare one task to another, it is to communicate that the first task is useless—by comparing it to a similarly useless task, such as rearranging deck chairs on a ship that famously sank into the sea on its maiden voyage.

Different Types of Analogy

In writing, there are two predominant types of analogies:

  • Analogies that identify identical relationships. The modern word “analogy” actually comes from the ancient Greek word for “proportionality,” and Greek scholars used analogies to directly illustrate similar relationships between two pairs of words, often for the purpose of logical argument. These analogies take the form “A is to B as C is to D.” An example of an analogy that identifies an identical relationship is “Black is to white as on is to off.” In this example, the relationship between black and white (that they’re antonyms, or opposites) is exactly comparable to the relationship between on and off (on and off are also opposites).
  • Analogies that identify shared abstraction. This type of analogy compares two things that are technically unrelated, in order to draw comparisons between an attribute or pattern they share. For instance, consider the analogy, “Raising children is like gardening—nurture them and be patient.” This example compares the pattern that is similar in both raising children and gardening. This type of analogy is useful in writing because it can help make abstract ideas (like raising children) more concrete by drawing on readers’ background knowledge of familiar images (like gardening).