Years ago, I was having a conversation with a teenager, who was indignant that a friend’s father didn’t believe her about something. She said, “We kept trying to convince him but he just wouldn’t listen to us.”
I said, “Oh, so you were lying.”
“No.”
“Yes you were.”
“Well, fine, yes.”
“Only liars try to ‘convince’ people. If you’re honest, you just say the truth. There’s no convincing.” Then I tried to put it into a memorable adage, but the best I could do was “Liars convince, non-liars … people telling the truth … honest people … just convey the information.”
Not as catchy as I would have liked, but better than my next alternative, which was “Read Act I of King Lear” (also not catchy).
The whole problem is there is no one-word equivalent for “Liar.” Why is that? I remember a rule from college that if you are name-calling, and there’s no racial or sexual equivalent to a name you are calling, then you should just shut up immediately. We discussed how there’s no W-word. (Though when I was in college no one said the phrase “N-word.” The person who suggested “Cracker” was an equivalent term was laughed at.)
I finally settled on “Liars convince, others convey,” but that was well after the time I needed the pithy adage.

2 responses to “Pithy”
I have had to convince lots of people of things that were true but which they initially didn’t believe (see: weird medical condition; some doctors with no experience with it literally have to see something happen to believe it), but yes, that is a pithy way of conveying the generally accurate principle. (generally accurate with the exception of people who we expect to be opposed to the actual truth about something, such as convincing small children that a new food might be worth trying, or convincing “nice” men that street harassment is a thing that happens pretty commonly)
And indeed, I think you found a linguistic gap! Maybe “honest people” is as close as we get to a negated liar?
KC – fair point. No doubt that’s why it wasn’t already an adage.