Argument from comparison

The Jane must be an excellent restaurant because Oud Sluis is an excellent restaurant.

The subjects are different and the predicates are the same, so the argument form is beta (a is X because b is X): “The Jane (a) must be an excellent restaurant (X) because Oud Sluis (b) is an excellent restaurant (Y)”.

Both the conclusion and premise are singular statements (s), so the argument substance is ss: “The Jane must be an excellent restaurant (s) because Oud Sluis is an excellent restaurant (s)”.

The keyword COMPARISON describes the relationship between subjects a and b. The argument lever can thus be formulated as “The Jane (a) is COMPARABLE to Oud Sluis (b)”.

Other examples

• You’ll love this book. You liked her last one!
• It is not best to change the president in wartime because it is not best to swap horses when crossing streams (adapted from a report of Abraham Lincoln’s reply to the Delegation from the National Union League on June 9, 1864).

Notes

The literature often treats the “argument from analogy”, “argument from similarity”, “argument from comparison”, and “argument from equality” as if they were the same. In the PTA, “argument from analogy” remains a broad, umbrella label (much like argument from sign in the Alpha Quadrant). However, its parametric approach to argument categorization allows for a more precise distinction between the other three argument types by using the distinction between statements of fact (F), value (V), and policy (P) that is used to determine the value of argument substance in the Alpha Quadrant. Applying these labels, it turns out that, typically:

• the argument from similarity has an F-claim supported by an F-claim;
• the argument from comparison has a V-claim supported by a V-claim;
• and the argument from equality has a P-claim supported by an F-claim.