Argument from similarity

You say what may happen to one thing by reporting what actually happened to another thing of the same sort. The argument works because the earlier case did turn out this way, and the present case is held to be enough like it for the same outcome to be open. It can be attacked by showing that the two cases differ in whatever made the earlier outcome possible.

Example

It is possible that the Tories will recover from their bad position because Labour recovered from their bad position in 2019

Standardised form

The Tories (a) can possibly recover from their bad position (X) because Labour in 2019 (b) recovered from their bad position (X).

Transformations applied: the opener “it is possible that” absorbed into the conclusion predicate; the date moved into the premise subject, so that “in 2019” identifies which Labour is meant rather than trailing the predicate.

Classification

The subjects differ and the predicate is the same, so the argument form is beta (a is X because b is X).

The conclusion is about one specific party (s) and the premise about one specific party (s), so the argument substance is ss.

The keyword SIMILAR describes the relationship between subjects a and b. The argument lever can thus be formulated as “The Tories (a) are SIMILAR to Labour in 2019 (b)”.

Not to be confused with

• Argument from analogy — The umbrella type: alike in form and substance, but the likeness is asserted as such rather than resting on a matter of record. ANALOGOUS
• Argument from comparison — What is transferred is an appraisal rather than a fact. VV
• Argument from equality — What is transferred is an entitlement, and the premise remains factual. PF
• Metaphoric argument — The second case is not a real comparable at all but a figure of speech. METAPHORICALLY

Source

Adapted from an article in The Guardian. The article is not identified on the type page; full citation not yet recorded.

Other examples

• “Nearly everything we had in the past (b) was recyclable (X), so nearly everything we have in the future (a) may be recyclable (X).” — source not yet recorded. “Establishing gun control in the present-day U.S. (a) will lead to genocide (X) because establishing gun control in historical Germany (b) led to genocide (X).” — adapted from a campaign ad featuring Joe Wurzelbacher, published on YouTube as “Joe the Plumber Ad: Gun Control Caused Holocaust”.

Notes

See the note on the argument from analogy.