AP® English Language and Composition · Big Idea 2
3.A Analogy, Example, and Illustration as Evidence
Analogy, example, and illustration support a claim by transferring belief from a familiar or specific case to the one in question, but each has a breaking point where the comparison or the single instance stops carrying the weight of proof.
An analogy works by lining up two situations point by point: if they match on the features that matter to the claim, belief flows from the familiar case to the unfamiliar one. That's why comparing a national budget to a household budget feels convincing - everyone has balanced a checkbook, so the logic of "don't spend more than you earn" feels obvious. It misleads for the same reason it persuades: the familiar case is doing the emotional work before anyone checks whether the two cases actually match. A household can't print money or issue debt in a currency it controls; a government with a multi-trillion-dollar budget can. The analogy snaps exactly where the point-to-point correspondence breaks.
Checking an analogy means testing each piece separately rather than accepting or rejecting the whole thing at once. Take "a city is like a living body," used to argue for widening a road: the idea that flow through a narrow passage gets choked, starving what lies beyond, holds up fine - that's just physics of constriction, true of arteries and traffic alike. But the argument snaps when it assumes widening works the same way in both systems. A wider artery doesn't generate more blood, but a wider road attracts more cars, a pattern called induced demand. Same structure, opposite result once you push past the surface.
Examples and illustrations work differently: they make a pattern vivid rather than transfer belief by resemblance. A single firm whose output rose after switching to a four-day week shows the outcome is possible, not that it's typical. One vivid case persuades because it's concrete and memorable, but a claim about a general pattern needs a pattern's worth of evidence, not one data point dressed up as proof. This is why writers pair examples with commentary that states the limits of what the example shows, connecting evidence back to the claim honestly.
Key terms
- Analogy
- A comparison that transfers belief from a familiar case to an unfamiliar one by matching their structures point by point.
- Point-to-point correspondence
- The matching of individual features between the two things being compared in an analogy.
- Induced demand
- The pattern where increasing a resource's capacity, like road width, increases the demand that uses it up.
- Illustration
- A vivid, concrete instance used to make an abstract claim easier to picture, without proving it holds generally.
- Commentary
- The writer's own sentence explaining what a piece of evidence proves and how it connects to the claim.
Watch it explained
- How it worksHow does an analogy carry belief from a familiar case to an unfamiliar one, matching point to point?
- Worked exampleShow me which parts of 'a city is like a living body' survive a traffic argument and which parts snap.
- Common mistakeWhy isn't one well-chosen example the same as proof that a pattern actually holds?
Check yourself
End of topic.