Instead of saying "we should believe that the Earth is round because it looks round when seen from the space", just say "the Earth is round because it looks round when seen from the space". The latter sentence is clearer and doesn't lack anything important which the former has.
The latter sentence parses as either malformed or false, to me. The earth appears to be round from space because it's round, not vice versa; the earth is round because of the forces that were involved in its creation.
I do agree that the 'should' needs to go, but I think the formulation should look something like 'it is rational to believe [thing] because [evidence]' or 'I/we believe [thing] because [evidence]'.
This is a good way to formulate it. I'll implement this now.
Edit - Barring a major surprise, this post should be regarded as a worthless artifact of my impulse to do things instead of talking about them. I apologize for any time wasted on this, and would recommend ignoring it unless it is for historical purposes. I'll just stick to things I'm less bad at from now on.
This article will be edited as people post and discuss.
I believe that we need to have a clear, concise statement about the beliefs, practices, and taboos that it is rational to hold, and that we already hold as a group. To be clear, this is not an attempt to make new norms, but an attempt to codify the ones that we already hold and to get a rough estimate of the popularity/importance of each.
Core Rational - skills, meta-beliefs, and habits that enhance personal rationality
Social Rational - norms that enhance working in groups rationally
LessWrong Norms - norms for dealing with Less Wrong specifically
Common Knowledge - basic, useful beliefs to build on
Please post one phrase at a time and then give your reasoning under it. Once any idea has a common consensus, I'll add it to this article in the appropriate list.
Edited - Removed the word 'should' as someone has suggested a better phrasing. Edited again - category change, remove extra now-useless examples.