In this answer ScottRowe and I had an on-topic comment exchange that was mysteriously deleted. As best I recall, this is what it contained:

  • Scott asked about the chance that a God hypothesis would be falsified in Solomonoff induction. This comment was deleted.
  • I responded that it's actually an infinite family of hypotheses, some of which would match the observations, so it's just a question of how long the shortest program is. This comment remains.
  • Scott asked about dividing by an infinite number of hypotheses. This comment was deleted.
  • I explained that Z is a sum of the probability mass, not the number of hypotheses, and takes on a value between 0 and 1. This comment was deleted, NOT BY ME.
  • Scott said we'd need a computer the size of a planet to calculate these probabilities. This comment was deleted.
  • I explained that yes, we cannot calculate them exactly, but we can make comparative estimates about which type of hypothesis would have a shorter or longer minimum description length. This comment was deleted, NOT BY ME.

Perhaps Scott deleted his comments, but two comments of mine were also deleted. By whom, and why? I feel these comments add something to the answer.

  • Right, I didn't delete mine (I have deleted ones related to "where did the comments go?"). I noticed this morning that comments from yesterday were gone, but that happens sometimes. The whole thing is getting pretty long.
    – Scott Rowe
    Commented Apr 1 at 17:04

2 Answers 2


It is your answer. If the comment thread adds something to the answer, you should edit your answer, to summarize what you have learned from that exchange or improve it based on the feedback you've received. Don't just leave important information in the comments. We want answers to be self-contained, so people don't have to read the comments to get the information they need, and to be written well for someone encountering them for the first time. If someone gives you feedback, usually responding with a comment containing more information is not the best way to handle it. Instead, revise your answer to improve it based on the feedback, and then flag their comment as 'no longer needed'.

Stack Exchange works differently from other sites people might be familiar with. This isn't a discussion forum. The purpose of comments is not to support open-ended discussion and back-and-forths on topics related to the question. The purpose of comments is to suggest improvements to the answer or highlight a flaw in the answer. In most cases, comments should normally be transitory, and lead to an edit to the answer. If you find yourself engaged in a discussion or back-and-forth or debate with someone in the comments, it is likely that you have gone beyond the purpose of comments.

Comments are second-class citizens and are routinely deleted. Don't put important material in the comments. There are multiple other options for how to respond that are often more constructive: if you can answer the question, write your own answer, taking into account what you've learned; if you can improve the answer, edit the answer to improve it and make sure all relevant information is found in the answer; take the discussion to chat; or sometimes, it is best to hold your peace.

Stack Exchange is not intended for discussion or debate. It is a site where people can collaborate to build an archive of knowledge, in the form of high-quality questions and answers that will be useful to others in the future. The site is designed to encourage you to direct your energy towards high-quality questions and high-quality answers.

You might also refer to "Not in comments please" -- How to handle interesting discussions, Why are comments not for discussion?, User suspended for posting too many comments....what?, Can we allow more space and possibly a larger font for comments?, How can I incentivize the conversion of some of these comments to answers?.

  • 2
    Normally if a discussion is getting too long it would be moved to chat rather than silently deleted. 3 back and forths also does not seem terribly long. To my knowledge in 3 years on this site I have never had a comment chain silently deleted. Additionally the purpose of comments is to eventually improve the answer by editing, and these particular comments would indeed have improved the answer if added to it, so it goes against the purpose of comments to just delete them before that might happen.
    – causative
    Commented Apr 1 at 21:21
  • 1
    I am concerned that they were deleted by a religiously motivated moderator who didn't like the things being said about God.
    – causative
    Commented Apr 1 at 21:23
  • @causative, There are no guarantees that comments will be moved to chat rather than deleted. If your comments are important to you, please edit the answer immediately, rather than relying on using the comment thread for interactive discussion. The site expects you to improve your own answer or suggest edits on other answers, rather than leaving comments and leaving that up to someone else to take care of at some indeterminate time in the future. Stack Exchange's format is designed to encourage you to place your energy on improving questions and answers, rather than on posting comments.
    – D.W.
    Commented Apr 1 at 22:35
  • I realize it might be a shock to discover this if you haven't been aware of this Stack Exchange philosophy before, but there is no time like the present to start adjusting how you use the site!
    – D.W.
    Commented Apr 1 at 22:38
  • 2
    Of course I have been "aware of this Stack Exchange philosophy." I've been using it for 3 years, I know how it usually works, and it isn't this.
    – causative
    Commented Apr 1 at 23:47
  • 3
    I've always felt a tension about SE sites, because they have much higher quality posts than the little that I have looked at elsewhere, it is the "local maximum" as best I can tell. But I never really got behind the idea of making a large and permanent collection of good questions and answers. Maybe I have just never seen it happen before. It is a lot easier to discuss than to research and develop an academic-level post. Too much like work :-) For finding computer programming info, I've often gotten crucial details from very short answers that were probably just casually tossed off.
    – Scott Rowe
    Commented Apr 2 at 1:57
  • 3
    Touche @ScottRowe!! Especially for philosophy to have ready cooked answers is patently absurd
    – Rushi
    Commented Apr 2 at 7:52

In all the SE policy documentation I’ve seen, it does explicitly say “comments are like sticky notes”, in the sense that, they are temporary, and liable to be deleted.

That said, it’s possible the policy is incomplete - hasn’t specified all possible scenarios. Since, I agree that there are some high quality comments (actually many), and I wouldn’t want a mod to delete them without feeling they had reasonable judgment.

Unfortunately, it’s not quick to try to change Stack Exchange. You could ask a mod who did that - perhaps a mod didn’t exercise the best judgment in this case.

  • 1
    I am asking, here, who did that. I don't think it's about me wanting "change" - this has never happened to any of my comments before. Rather, this deletion is the change that needs an explanation.
    – causative
    Commented Apr 2 at 19:29

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