If you hear "logos," think "logic." Going way, way back to Aristotle's Rhetoric, logos is a type of appeal—along with ethos and pathos—that you might make to get your audience on board.
But unlike those other categories, logos is all about logic and reason. So if you're using a statistic to prove your point, or predicting the next (logical!) step in a chain of events, then you're assuming that the best way to change your listener's mind is to bombard him or her with facts and reason. You know, make 'em feel all smart and sane.
Well, you might have a point. According to the Shmoop Association for Rhetorical Research, 99% of Shmoopers respond favorably to facts. And 75% found sentences using "if-then" logic more persuasive than sentences with "might" or "maybe." Convinced?
We certainly are.