Argument From Analogy

An example.

P1: I always have fun watching movies with my friend Nick.
P2: Yet Nick can’t go to the movies tonight, and I want to see a film.
P3: But my other friend Bert is a lot like Nick.
P4: Even if I have not gone to a movie with Bert before, I feel I will enjoy watching one with him, since he and Nick are similar in terms of personality.
P5: Bert is free tonight.
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Hence I should go to a movie with Bert tonight.
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There are a few ways to argue from analogy, but here is what most of the arguments have in common:

P1: S is P (where P is any description)
P2: R is similar to S
C: So R is probably P as well

To make it clearer, let’s fill in the letters…

Say that:

S = Sally
R = Robert
P = someone who enjoys horror movies

So… the argument becomes:

P1: Sally is someone who enjoys horror movies
P2: Robert is similar to Sally in many ways
C: So Robert is probably someone who enjoys horror movies as well.

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