Lets see how did that saying go?  Oh.  "Better to keep your mouth closed and be thought a fool, than open your mouth and prove it."

Now in response to Rabi's questions:

1-Do we need to produce links for proof of the theory of gravity?  No, that would get tedious and no one would want to post anything.  If there is some challenge to that known fact, it would be helpful to provide a link if it's a valid part of the discussion but if it's a very tangential point, probably not. 

2-I think this is acceptable for example if you have a book where you read something that you want to quote but it's not availiable online, you could probably give a link to the book on Amazon (or wherever) and directly quote from the book as long as you give credit to the source.  If it's in another language, a link would also be appropriate as long as you made an attempt to at least give an overview.  That said, it would probably not be a very effective debate tool as we'd have to take you at your word.

3 & 4-Only if you are giving facts to back up your moral belief.  If you say, abortion is bad because millions of babies die a day, give some kind of validation of that.  If you are arguing that abortion is evil regardless of how many lives are taken, no, I don't think you'd need a source on that since it's your opinion.

5-Not sure on that one.  I often don't post because I just don't have time to look up my facts so some of my points just aren't made.  Should it be a rule?  Probably not.  I will say, it is fine by me if someone says, "it is my opinion that..." and has no source to quote.  What I have a problem is when people say, "it is a fact that..." and has no source to quote from.

The issue of the nature of sources is not going to be closed up nicely with a single preemptive policy discussion. The world (particularly the political, religious, historical, and social world) are full of contrary views.

Many things that large segments of humanity regard as "fact," other segments regard as hoaxes, fabrications, or outright lies, including: the Apollo moon landings; paleontology; historical geology; modern history; ancient history; in-between-age history; etc.

If two people disagree because they come from different traditions, and are referring back to different "sources" (whether those sources are the gossip in their communities, what their elementary school teachers told them, or what they read in a book) the key thing is that the basis for their disagreeing should not be obscured by the nature of their discussion. In short, I think if we are all simply prepared to provide clarification of our "sources," that is about the best that can be hoped for.

Opinions, beliefs, attitudes, convictions, faith, that sort of thing, never have, and never will be necessarily dependent on facts, so no need to whip the dead horse there. As long as people are willing to acknowledge where certain elements of what they say or express on here derive from these objectively uncorroboratable sources, again, fine too, best that can be hoped for.

Unless of course Sean wants to restrict the nature of the discussions on the site to be more like a courtroom in which disputants can object, overrule, and dispute claims based on their subjectivity, or lack of objectivity. I doubt that that is the intent. But at least having a general intent that, any poster in P&R should be willing to acknowledge (or perhaps even be shown through analysis of their discourse) that what they claim is or is not objective/subjective is probably about the best that can be wished.