Correction: This article originally stated that the square root of 9 is 6. The article has been corrected.

See that correction? That’s not real. At no point did I misstate the square root of 9 in this article. Had I done so, though, getting a basic fact like that wrong, such a correction would have been the result, sitting at the top of this article for everyone to read every time they come to this page. That’s how it works for articles on the Web from institutions interested in self-correction. For a writer, it’s painful, like executing a risky series of tricks on a snowboarding halfpipe only to have your wipeout go viral (to use a far cooler analogy than is warranted). But that is how it works.

This is not how it works on television. There are several important differences between television and writing online. One is impermanence: If you read these words, it’s easy to come back and read them again if you wish to, whereas, on television, most commentary is transitory. Another is density: I can transmit a lot more information in writing than I can by speaking over the same period of time. (You just read the beginning of this paragraph. Now go back and read it out loud. Which was faster?) A third is constraint: If your show is one hour long, you have one hour. That’s it.

So when something inaccurate is said on television, it’s much harder to correct. Any on-air correction that isn’t a flash in the lower third eats up programming time. In part, that’s because you have to give the context for what it is that you’re correcting, since it’s not accompanying the original story. (This is a challenge for corrections in the print newspaper, too, although there we have more space to play with.) And, then, that explanation on TV takes longer than a written one because speaking is slower than reading. That’s a lot of disincentive for on-air corrections — and certainly one reason we so infrequently see them.

That’s if you want to correct your mistakes, which Fox News and Tucker Carlson very obviously don’t.