(Thought I'd try posting here some various rationality "quick thoughts" that I feel like I haven't seen expressed overtly enough -- sometimes I've already written about these elsewhere, but thought would be good to get them down here. Not claiming any originality here.)

I think the principle of charity is frequently used in ways that are unhelpful, and I want to make some suggestions on doing principle-of-charity better.

The first thing note I would make is to never apply the principle of charity silently. That is to say, if someone says A, and A seems to you like someone could not possibly assert in good faith, don't just act as if they said reasonable variant B instead and reply to B; explicitly say something to the effect of "A doesn't appear to make any sense to me; did you perhaps mean B? If that is what you meant, then..." Otherwise, you're just deliberately inflicting the AB problem on yourself!

This is especially the case because in many cases there's not a single clearly best charitable interpretation. A common case is when someone makes a statement that has two possible interpretations: One interpretation is interesting but stupid, while the other is true but trivial. (Aka: A "deepity", a troll's truism, or (a special case of) motte-and-bailey doctrine.) What's the charitable interpretation here -- assuming your interlocutor wouldn't deliberately say something stupid, or that they wouldn't deliberately say something trivial?

The answer of course is that this is a silly question because you should never invoke the principle of charity silently. Don't assume -- ask! Say explicitly what you think is going on (although uh probably don't call it "stupid", that's not nice) and ask which interpretation is meant. You can also just not wait for the response, and respond to both possibilities in advance. Doing principle-of-charity correctly sometimes involves a fork.

Before we go further it's worth asking the question, what's the point of the principle of charity anyway? Well the answer is that since it isn't truly a designed thing, more of an evolved thing, it doesn't actually have a singular purpose; rather it seems to potentially have multiple. One purpose might be making people confront the strongest version of their interlocutor's ideas, hence steelmanning -- but see "Against Steelmanning".

But often the main point of saying "assume good faith" is just getting people not to assume bad faith, as so many are eager to do. The assumption of bad faith shuts down discussion; the point of the principle of charity is to allow discussion to happen at all. So in fact I wouldn't truly say "assume good faith" -- that'll get you in trouble on the occasions you do run into a bad-faith actor -- but rather, always keep in mind the possibility of good faith.

(On that note, I wish people on the internet would use the word "disingenuous" a lot less -- maybe just scrub it from their productive vocabulary entirely. Perhaps not everyone realizes that it's an accusation of bad faith and may be taken that way? If you think something is misleading, just say it's misleading! There's no need to go further and say it's disingenuous, i.e., deliberately misleading. Again, maybe many people think "disingenuous" just means "misleading", and if you're discussing solely among such people I guess that's fine... but a lot of people are going to take it at its dictionary definition. So don't use it!)

This is often another case where you need to fork. What do you when it actually seems to you like someone is arguing in bad faith? You keep in mind that they likely aren't, and address both possibilities. Maybe don't actually start addressing the bad-faith possibility on your first response, maybe wait for the second or so.

Remember: Don't fall into the AB problem! Someone isn't arguing in bad faith just because of implications that you accept. Get them to actually clarify which implications they do and don't accept. If they seem to contradict themselves, don't immediately conclude bad faith; point out the contradiction and see how they respond. Or if someone brings up a point you've already addressed, point out that they're doing so; if they dodge a question or don't answer it satisfactorily, point that out too.

But obviously there is a point where if someone does all this repeatedly you can conclude bad faith and give up. Until then though you should maintain the fork! Isn't this a lot of work? Yes, it is. Arguing well often is, unfortunately!