There is no use talking to the ignorant about lies, for they have no criteria.I found this one, I suspect, on Brian Leiter's blog, since he's quoted it a number of times (with slightly different wording -- "You can't talk to the ignorant about lies, since [or because] they have no criteria". But I went and dug up the original citation for this blog post, and the original context is interesting -- you can read the whole thing here, it's only a page and a half. It's Pound denouncing the idea that poetry is meant to entertain as "flatter[ing] the mob". But, of course, it's a good line (and an important truth) whatever one thinks of its provenance. A truth's not responsible for the person who first expressed it.
- Ezra Pound, "The Constant Preaching to the Mob"