In 2014, Scott Alexander wrote this description of the comment policy on his blog (then called “Slate Star Codex”). I'd like to adopt it here for this Forum:

There is an ancient Sufi saying beloved of the Buddha, which like a surprising number of ancient Sufi sayings beloved of the Buddha, originates from a book of preachy Victorian poetry. It goes:

“Before you speak, let your words pass through three gates; At the first gate, ask yourself, is is true? At the second gate ask, is it necessary? At the third gate ask, is it kind?”

Slate Star Codex has lower standards than either ancient Sufis or preachy Victorians, and so we only require you to pass at least two of those three gates.

If you make a comment here, it had better be either true and necessary, true and kind, or kind and necessary.

Recognizing that nobody can be totally sure what is or isn’t true, if you want to say something that might not be true – anything controversial, speculative, or highly opinionated – then you had better make sure it is both kind and necessary. Kind, in that you don’t rush to insult people who disagree with you. Necessary in that it’s on topic, and not only contributes something to the discussion but contributes more to the discussion than it’s likely to take away through starting a fight.

Nobody can be kind all the time, but if you are going to be angry or sarcastic, what you say had better be both true and necessary. You had better be delivering a very well-deserved smackdown against someone who is uncontroversially and obviously wrong, in a way you can back up with universally agreed-upon statistics. … And it had better be necessary, in that you are quashing a false opinion which is doing real damage and which is so persistent that you don’t think any more measured refutation would be effective.

Annnnnnd sometimes you might want to share something that’s not especially relevant, not the most important thing in the world – but if you do that it had better be both true and kind. No random interjection of toxic opinions that are going to cause World War III. No unprovoked attacks.

Threats, doxxing, most things people would call “slurs”, et cetera fail this test as neither kind nor necessary. You people are smart and don’t need me to explain this further.

I feel like these standards are pretty lax. In fact, they probably permit most spam – this spambot saying “this is a wonderful piece of writing” is both true and kind – so I will inelegantly add a kludge that spam is also unacceptable (I have it on good authority that this was in the original Sufi saying used by the Buddha as well). Remember that before you worry this is too unduly restrictive.