How reliable is Wikipedia?

How do you combat the use of obscure (but "reliable") sources on Wikipedia?

• Let's say there is a reliable source. It's written by a university professor and checks out via Wikipedia's reliable source guidelines. BUT, at the same time, it seems to violate Wikipedia Neutrality rules by being an extremely obscure opinion. Recently, I got into a disagreement on Wikipedia regarding the use of very obscure sources in an article. They qualified as "reliable" but the opinions shared by the source authors did not seem to be shared by anyone else that I could find, despite extensive research. However, when I tried to remove this material for its obscurity and replace it with more reasonable material, my changes were reverted by a very insistent user who says that my claims of obscurity are invalid-- because I did not cite a source. But here's the problem: how can I cite a source to combat an obscure source, or an obscure claim? This particular claim is so unheard of that there isn't even a source that directly challenges it. What am I supposed to do: read a book and say, "well, this doesn't mention it, so there's your proof..."? I'm not sure what to do here. It seems like Google and other thorough source searches would be the only way to go about proving obscurity. And to make matters worse, these obscure (and highly controversial) claims are being made in the introduction to an article. They make something out to seem like a big issue, when in reality it patently is not. So much so that no one even talks about it. How do I prove a source is obscure and get its material removed? Assuming this is a situation where the source is so specific and obscure that there isn't a way to add a proper counterargument.

• Answer:

  This is not an issue of reliable sources, but giving sources due weight (policy WP:DUE). If it is not too obscure, it should be represented as a minority opinion (e.g. "The prevailing view is X, but Prof. A has an alternate view,...."). If the opinion is published but not cited by anyone in the same field, it may be too obscure for mention.