Claiming that something is true because the person making the claim has experienced, or is referring to someone who has experienced, some practical benefit from believing the thing to be true. The practical benefit is often summarized as “it works.
Examples:
- _Starbeam: Of course, astrology is true!
Nate: How do you know this?
Starbeam: Because on the days I forget to consult my horoscope, things always go wrong._