Should Stack Exchange make room for conjecture? Or experience/knowledge based ideas?
My question is a philosophical one. If we are to assume that the full breadth and capacity of human knowledge has been reached and can be referenced by online/literary sources, then by all means, we should demand that every claim, response or idea should be cited. However, if we admit that there are very creative and valuable thoughts and ideas that have not been conceived, then we should have a system within Stack Exchange to allow for this sort of discourse.
For instance, there may be a contributor out there who has vast knowledge in a particular field. Their ideas may be so bleeding edge that they are widely considered highly unconventional and/or controversial. There may not be any research to back up their claims. If he were to make a post that someone didn't agree with, his answers would get voted down, he may lose reputation and he may eventually become frustrated and decide to leave the site and not contribute further to the community. I think this is an unfortunate situation and one to be avoided. Creative and unconventional thought forms the very basis of scientific and analytical understanding. I don't think Stack Exchange should discourage outside-the-box thinking and conjecture.
Another more practical example would simply be the case of your typical professional who comes across a Stack Exchange site and would like to contribute. It's very simple for someone with lots of experience in a particular field to answer many questions from a very abstract or big-picture point of view in relative short order. But to ask this same person to back up every claim and every admonition with references may cause the professional to choose not to devote his time to contributing. Again, I think this is an unsatisfactory outcome.
All that being said, I do not think opinion, conjecture, experience and knowledge based answers should go unchecked. But I also don't think these contributions should automatically be seen as unhelpful to the community. Perhaps Stack Exchange would benefit from implementing a system of flagging an answer or portions of an answer as conjecture or knowledge-based or what have you. And perhaps this could grab the attention of the community somehow and promote a discussion where further explanation could be asked of the poster. Personally, I think ideas which challenge the status quo should get more promotion than those that don't. Maybe they could be highlighted as "novel" or "unique" and contributors could vote separately on this response to decide it's relevance to the question and perhaps its ultimate position in rank.
I think the worst thing is to allow voting down and simply ignoring responses of this nature. It's unproductive and stifles creativity in this community.