Constructing Illustrative Parallels

In my last post, I claimed that there are three typical ways we use analogies: basic comparisons, ordered-pairs, and illustrative parallels. In this post I will explain how to construct an illustrative parallel, which is a powerful means of proof.

The Pattern

An illustrative parallel reasons from a particular example (the source) to a particular conclusion (the target). The process combines inductive reasoning (from the particular example to a general statement) and deductive reasoning (from the general statement to the particular conclusion) as shown:

I am fascinated by the inductive-deductive process that the mind goes through when reasoning by analogy, such as in the parables. For example, Jesus teaches in Matthew 5:14-15, “You are the light of the world. A city that is set on a hill cannot be hidden. Nor do they light a lamp and put it under a basket, but on a lampstand, and it gives light to all who are in the house.” The source (“no one lights a lamp to put it under a basket, but to give light to the house”) inductively implies the general intermediate conclusion that what is meant to illuminate something should not be covered, and that it is uncovered not in order to display itself, but something else. So when he deductively makes the particular conclusion in verse 16, “Let your light so shine before men, that they may see your good works and glorify your Father in heaven,” we understand that we should do good works, not to shine a light on ourselves, but that men might glorify God.


Inventing good analogies can be difficult, but we can be helped using the pattern above. Say that you want to use an analogy to respond to this challenge: “Why study formal logic? Everyone can already reason!” You could argue that the study of formal logic helps to improve our reasoning skills by providing standards to distinguish between good and bad reasoning. This is your target. It can be deduced from the general statement that studying a language art can provide standards by which we distinguish between the proper and improper use of that art. Given this, we must then invent a source, a different example of the general statement, and one that is preferably more familiar that the target. What familiar language art provides us with such standards? English is a good example; the study of English helps us improve our speaking and writing skills by providing standards to distinguish proper English from improper. The basic analogy could then be simply stated: “‘Why study formal logic? Everyone can reason.’ That’s like arguing, ‘Why study formal English? Everyone can speak!’”

Imitating the Masters

Jesus is, of course, the Master of analogies, as of all other forms of argument. But there are also many lesser masters from whom we can learn this art. My favorites include C. S. Lewis, G. K. Chesterton, Mark Twain, and Doug Wilson. Here are some of my favorites:

“I believe in Christianity as I believe that the Sun has risen; not only because I see it but because by it I see everything else.” ― C. S. Lewis

“The object of opening the mind, as of opening the mouth, is to shut it again on something solid.” ― G.K. Chesterton

“Laws are sand, customs are rock. Laws can be evaded and punishment escaped, but an openly transgressed custom brings sure punishment.” ― Mark Twain

“We have no structure any more. We have no shared creed. We do not know what we are here for. It makes no sense to speak of our inherited ‘shared values,’ or better yet, ‘core values.’ If they are arbitrary, shared values are worthless. If they are arbitrary, core values are simply located where our intestines are, and are full of the same thing.” ― Doug Wilson

“If we had no winter, the spring would not be so pleasant: if we did not sometimes taste of adversity, prosperity would not be so welcome.” ― Anne Bradstreet

What are some of your favorite analogies? Leave a comment!

2 thoughts on “Constructing Illustrative Parallels

  1. Thank you for this! What I found most helpful was the layout of a typical illustrative parallel as [A] an abstract idea compared to [B] a familiar image by means of [C] a shared concept. So A is C, and B is C, therefore A is like B. But what is the difference between a comparison and an illustrative parallel? Is comparison the genus, and illustrative parallel the species?
    Here are a few of my favorites… though I can’t figure out if they are comparisons or illustrative parallels:

    1] Women are like apples on a tree: the bruised and squashy ones can be picked up off the ground, but the best and most beautiful ones are hardest to reach.

    2] Emotions are like waves: you can’t stop them from coming, but you can choose which ones to surf.

    3] Robert Frost’s poem `The Road Not Taken’, which compares a decision to a fork in the road – you must choose a direction, and every decision leads to more and more decisions, and it’s unlikely you’ll ever go back.

  2. Great questions! You are correct in saying that an illustrative parallel is a species of comparison. The further distinction is that illustrative parallels are arguments; they have a conclusion. In a previous post I said that illustrative parallels are “analogies being used for the purposes of persuasion” also called “arguments by analogy.”

    I like your favorite analogies! I would say that these either are or can easily be turned into illustrative parallels, which you’ve put in order from easiest to hardest (for me). The context could make it clear, e.g. “You should take the effort to win the heart of a beautiful woman, because…”; “Don’t let yourself be overwhelmed by your emotions, for…” Not sure how to turn Frost’s poem into an argument.

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